Joey D
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- Boyne Falls, MI
- GTP_Joey
- GTP Joey
Alright lets try this again, this is purely a informational thread.
Stay tuned for updates, I will give them when I can.
Here is all the information on the GMT 900 line of trucks.
Source: www.gminsidenews.com
2007 GMT-900 Information
Comprehensively redesigned chassis and suspension systems of the 2007 GM full-size SUVs are the backbone of a refined feel and effortless driving experience. The athletic, responsive tuning of the vehicles establishes a new benchmark for full-size SUVs, while providing the driver with a heightened feeling of control.
The all-new chassis, with wider front and rear tracks, and new coil-over-shock front suspension support ride and handling characteristics that reinforce the SUVs live big, drive small mantra. These components provide a more agile feel and help deliver an exceptionally smooth ride, enhanced quietness and an overall feeling of strength and stability.
The strength of the new chassis supports the refined feel that is like no other full-size SUVs vehicles that live big, but drive small, said Terry Woychowski, vehicle chief engineer for full-size trucks. The combination of a stronger chassis and refined driver control features helps give the vehicles an effortless, controlled and smooth driving experience.
Features of the new chassis and suspension systems include:
* A new, fully boxed frame that is significantly stronger and stiffer with hydroformed front and rear bay sections
* Wider front and rear tracks approximately 3 inches (76.2 mm) in front and 1 inch (25.4 mm) in rear enable increased stability, as well as a smoother, more controlled ride
* New coil-over-shock front suspension delivers linear, responsive ride and handling characteristics
* Highly refined five-link rear suspension (with variable-rate springs) delivers damped, isolated road feel and supports a variety of load-carrying capabilities
* Use of monotube Autoride shock absorbers for more controlled, real-time damping capability
* New rack-and-pinion steering system delivers precise, responsive steering and contributes to the vehicles drive small feel
* All-new four-wheel disc brake system larger vented discs, stiffer calipers, more robust apply system and standard next-generation Bosch ABS system provides shorter stopping distances, better pedal feel and quicker brake response
* Larger-diameter standard and available wheels and tires, including segment-largest, 22-inch designs available on Cadillac Escalade
* Standard StabiliTrak electronic stability control with first-time GM application of rollover mitigation a software algorithm technology that uses system sensors to proactively predict vehicle tip-up and applies appropriate brake forces to prevent rollovers.
Fully boxed frame
For the first time, GMs full-size SUVs feature a fully boxed perimeter-type frame, the foundation on which the chassis, suspension, powertrain and body systems are mounted. Chevy Tahoe, GMC Yukon/Yukon Denali and Cadillac Escalade ride on a 116-inch (2,946 mm) wheelbase. Other models ride on a longer, 130-inch (3,302 mm) wheelbase.
The new, boxed frame design offers 49-percent increased torsional stiffness (side-to-side twisting) and 35-percent improved beaming frequency (front-to-back bending), compared with previous-generation vehicles. The stronger frame also supports an increased load capacity of approximately 5 percent.
The frames overall strength and increased stiffness are combined with more precise, integrated mounting brackets for powertrain, suspension and axle components, which enabled engineers to tune chassis and suspension bushings, springs and other elastomeric components for more accurate and refined ride and handling characteristics. The result is smoothness and responsiveness, with the capability expected of a full-size SUV. Quietness, a more linear driving feel and the feeling of isolation from the road also are enhanced.
A variable-height design of the boxed frame is matched with strategic application of high-strength materials throughout. The frame also has three distinct frame sections, or bays, each with specific strength and support characteristics. The front bay of the frameis an all-new design and features hydroformed frame rails made of high-strength steel.
The front bay includes the radiator support cross member, engine support cross member and front lower control arm cross member, all of which are welded to the hydroformed frame rails. GM pioneered the use of hydroformed frame rails for full-size SUVs on the previous-generation vehicles, introduced in 2000. The process uses highly pressurized fluid up to 20,000 psi to shape the frame rails. The revised design of the 2007 full-size SUV front bay section is approximately 40 percent stiffer than the previous-generation without a significant difference in mass.
A new powertrain mounting system is part of the front bay section. It is welded to the engine cross member and includes very stiff mounting brackets for the engine and transmission. The brackets house unique elastomeric bushings (on vehicles not equipped with Displacement On Demand) to dampen vibrations and foster a smoother ride and feel inside the passenger compartment. Vehicles with Displacement on Demand-equipped powertrains used hydraulic mounts to accommodate the changing rotational forces associated with the cylinder-deactivating technology.
The middle bay section of the frame extends from the A-pillar area to the C-pillar area. The boxed side rails of the middle bay support three stiffness-enhancing cross members. Strength also is built into joining of the front bay to the middle bay, with the front bays hydroformed rails slipping inside the boxed sections of the middle bay. This shingle-type design is welded and reinforced with a high-strength steel close-out plate that covers the overlapped joint.
The side rails of the middle bay section are constructed of two pieces of high-strength steel that are welded to form the sturdy box design. The outer section is made of 60-ksi steel that is 3.3 mm thick; the inner section is made of 30-ksi steel that is 2.2 mm thick. The rails also have a variable-height construction (between 110 mm and 210 mm) that enables strategic placement of strength-enhancing materials in certain areas for a more integrated, lower-mass design.
The rear bay frame section extends rearward from the C-pillar. Like the front bay section, its boxed rail sections are hydroformed and are joined to the middle bay with an overlapping, shingle-type construction. The rear bay section offers enhanced strength via a stronger, single-piece spare tire cross member, a more robust fuel tank carrier cross member and a thicker rear track bar cross member for the five-link rear suspension.
Wider front and rear tracks
The 2007 full-size 1500-Series SUVs have wider front and rear tracks than previous-generation models. The front track is more than 3 inches wider (77 mm) 68.2 inches (1731.8 mm) vs. 65 inches (1651 mm). The rear track is more than 1 inch wider (25 mm) 67 inches (1701.8 mm) vs. 65.98 inches (1675.8 mm).
A wider track promotes overall vehicle stability and a lower center of gravity, which the driver and passenger can feel through the vehicles secure ride and handling attributes, as well as flatter, more controlled cornering. The wider track widths also enhance smoothness.
Coil-over-shock front suspension
A new coil-over-shock front suspension is used on all light-duty models, along with a new front axle mounting system. The coil-over configuration offers smoother, more precise and nimbler ride and handling characteristics, especially with the larger wheel-and-tire combinations offered on the new SUVs. Vibration and harshness also is greatly reduced when compared to the previous-generation torsion bar front suspension design.
The new suspension system uses specially tuned coil springs and 46-mm monotube shock absorbers (except vehicles equipped with Autoride), along with steel upper control arms and forged aluminum lower control arms. The aluminum lower arms reduce un-sprung mass by approximately 20 pounds (9 kg) and the responsive monotube shocks bolster the vehicles more nimble driving feel.
Complementing the coil-over suspension design are new, stiffer frame attachments for the suspension components and a new, four-point front axle mounting system. These stiff, accurate mounting points including softer bushings located within brackets of the stiff front bay frame section contribute to the vehicles more controlled and linear driving feel.
Five-link rear suspension
A five-link rear suspension is used for 1500-Series 2WD and 4WD models (a heavy-duty leaf spring design is used on 2500 models). Although similar in design to previous models, the 2007 SUV rear suspension features a more robust rear axle design that offers increased payload weight. The axle system enhancements include a stiffer track bar bracket mounted to the rear bay frame section, a redesigned axle carrier and an axle rear cover that is 50 percent thicker for increased strength and durability.
Like the front suspension, the rear suspension uses new, stiffer frame mounts for suspension component attachment, along with variable-rate springs and monotube shock absorbers (except when equipped with Autoride). The accuracy and responsiveness of the tuned springs and monotube shocks provide superior dampening and ride control, regardless of whether the vehicle is carrying or towing a heavy payload.
Autoride real-time damping system
Vehicles equipped with the Z55/G59 suspension package include the segment-exclusive Autoride bi-state, real-time damping system. This advanced system enables an extremely refined ride with greatly reduced body motion. It also delivers instant suspension response to wheel speed, body position, vehicle speed, steering angle and braking.
Autoride is a semi-active, two-position damping control system that responds in real time to road conditions and driving conditions, based on body and wheel motions determined through sensors positioned at all four corners of the vehicle. The system uses up to four two-position monotube shock absorbers (each with an internal solenoid valve and air-lift/auto-leveling capability), four wheel-position sensors, a steering position sensor, engine torque monitor, brake apply sensor, vehicle speed sensor and an independent controller. Independent damping control at each corner of the vehicle allows specific damping to control body motions during higher-speed turns and driving over uneven surfaces.
Autorides air-lift/auto-leveling system includes air bags located over the shocks. An integrated air pump automatically adds air, when needed, to increase pressure in the air bags, raising the suspension to level the vehicles ride height when carrying passengers or a heavy payload. Conversely, air is bled from the bags when the payload is removed, returning the vehicle to a level ride height.
Suspension choices
The 2007 full-size SUVs are available with three distinctly tuned suspension systems, each tuned to provide an optimized ride with smoothness, a greater feeling of isolation from the road and minimal body movement:
* ZW7 Premium Smooth Ride: standard on 2WD and 4WD Chevy Tahoe and Suburban, GMC Yukon , Yukon XL, Yukon Denali and Yukon XL Denali
* Z55 (includes Autoride): standard on Cadillac Escalade, Escalade ESV and Escalade EXT; available on Chevy Tahoe and Suburban, GMC Yukon , Yukon XL, Yukon Denali and Yukon XL Denali
* Z71 Off Road: available on 4WD Chevy Tahoe and Suburban, GMC Yukon and Yukon XL
Both the ZW7 and Z71 suspensions use 46-mm front and rear monotube shock absorbers and tuned springs. The shocks feature large rod diameters that help reduce shock lag and fade over time. The ZW7 suspension uses variable-rate rear springs an uncommon feature in the segment to maintain body height and attitude under various payload conditions.
The unique Z55 suspension with Autoride uses automatically controlled air bags to regulate body height when the vehicle is loaded or unloaded. It also uses springs made of micro-alloy steel, which is stronger than typical spring steel yet offers mass savings.
All three suspensions have distinct bushing, spring and material characteristics. The firmness of the bushings, the spring rates and related materials were carefully selected after countless hours of comparison testing at GMs proving grounds and real-world testing on roads of varying conditions throughout North America . Suspension tuning also is specific to the size of the wheels and tires, as the 2007 SUVs offer a range of wheel sizes from 17 to 22 inches.
Rack-and-pinion steering system
For the first time on GMs full-size SUVs, a hydraulic power-assisted rack-and-pinion steering system is employed. The result is an optimized on-center steering feel and more immediate, precise steering response.
The new system mounts on the engine cross member of the front bay frame section, directly beneath the engine. This mounting position uses the inherent stiffness of the frame to enhance the direct and linear feel of the steering system, reducing the drivers need for continuous corrections during turns and sweeping corners. On 4WD vehicles, the steering rack is located forward of the front differential.
Steering ratios vary, depending on the vehicles suspension choice and wheel size. Combined with more immediate responsiveness, this gives the new 2007 full-size SUVs an easier, more maneuverable feel, particularly when parking in tight quarters. Low-friction, highly precise ball-and-needle bearings within the steering system contribute to the precise and immediate feel from the steering wheel. The system also is engineered with low-noise valve technology that helps reduce noise and vibration.
Four-wheel disc braking system
A new brake system design with larger four-wheel discs and an all-new ABS system helps GMs new full-size 1500-Series SUVs deliver superior braking performance with assuring pedal feel. The system includes larger-diameter rotors, stiffer front calipers and longer-life brake pad linings.
The front rotors measure 13 inches in diameter (330.2 mm), an increase of 1 inch (25.4 mm) approximately 15 percent larger. The front rotors also are thicker with large cooling vents, providing enhanced performance and durability. The cast iron, dual-piston front brake calipers are 50 percent stiffer than before, which reduces the tendency for flexing during hard or prolonged braking. The stiffer calipers, along with dual pistons, contribute to a more direct, linear and stronger brake pedal feel.
At the rear, the standard vented discs measure 13.5 inches (342.9 mm), an increase of 0.5 inch (12.7 mm) approximately 7.5 percent larger. A revised single-piston rear brake caliper design contributes to reduced brake noise and more immediate braking response. Both the front and rear brakes use new, non-asbestos brake pad linings that can deliver up to 40,000 miles of performance during normal use.
The new brakes are complemented by a new, twin-piston design brake application system, including a larger master cylinder and active brake booster. The more robust design enabled engineers to tune the application system to optimize pedal feel and brake system responsiveness. The system requires less pedal pressure to provide a more immediate brake response, delivering a dramatically improved feel.
A next-generation Bosch 8.0 ABS system is standard on all 2007 full-size SUVs. It has more precise valve control that requires less cycling of fluid from the brake master cylinder, resulting in reduced noise and enhanced braking feel when ABS is activated during a braking event. The new ABS system also is less complex and has reduced mass when compared with the previous system.
StabiliTrak electronic stability control
GMs sophisticated StabiliTrak electronic stability control system is standard on all 2007 full-size SUV models. Partnered with the new brake system and four-channel, four-sensor electronic brake controls, the system provides more precise, controlled ABS stops, as well as enhanced traction/yaw stability. The new, larger brake system allows for smoother, quieter StabiliTrak interventions and includes an active vacuum booster to increase system response time to changes in vehicle behavior.
On 4WD models, StabiliTrak uses brake control to precisely control the speed of each wheel and manage torque across the front and rear axles. On 2WD models, the system precisely controls the speed at each wheel and manages side-to-side torque on the rear differential. Individual brake sensors at each wheel provide instant signals to the control module, enabling it to aggressively adjust brake pressure. However, traction is controlled by transferring torque across the rear axle rather than front and rear axles, as in 4WD models. When the vehicle is on a slippery surface, the traction system increases torque to the rear wheel that has the most traction.
On 2WD and 4WD models, the vehicle brake system provides the torque-biasing to enhance traction and engine management is used, as required, to assist in controlling traction and yaw stability. The Autotrac transfer cases control algorithm has been integrated with the StabiliTrak and ABS systems to provide enhanced vehicle stability by managing the front-to-rear torque distribution.
StabiliTrak is always on and fully functional. It is automatically enabled, providing full stability, traction and ABS control, whenever the vehicle operates in forward gears. The system intervenes when it senses one or more of the wheels slipping or when the vehicle is not following the drivers intended path. It detects slippage during braking or acceleration and automatically adjusts individual wheel brake pressure, engine torque and, on 4WD Autotrac models, adjusts front to rear drive torque distribution, as required, to achieve optimal control.
Rollover mitigation
The Stabilitrak system has new rollover mitigation technology. This technology adds software algorithms that use Stabilitrak sensors to proactively predict vehicle tip up on a flat road surface, and applies brake force to the outside front and rear wheels in order to reduce lateral force in the vehicle. This brake force intervention can help reduce the likelihood of a rollover in certain circumstances.
Wheels and tires
Complementing the strong, athletic styling of the 2007 full-size SUVs is a range of large standard and available wheel and tire sizes, including segment-largest 22-inch wheels and tires available on the Cadillac Escalade. New P-metric tires for 18-, 20, and 22-inch sizes have a nylon cap ply that enhances strength and durability.
Chevy Tahoe and Suburban, along with GMC Yukon and Yukon XL, come standard with 17-inch wheels and touring tires that provide excellent comfort and low road noise. Uplevel models offer styled aluminum wheels different designs for Chevy and GMC models including machine-face and polished-face wheels. Tahoe, Suburban, Yukon and Yukon XL also offer optional 20-inch wheel-and-tire combinations, including six-spoke, bright-face aluminum wheels. Eighteen-inch wheels are standard on GMC Yukon Denali and Yukon XL Denali, with 20-inch wheels optional.
Cadillac Escalade models come standard with 18-inch aluminum wheels, with a 22-inch wheel-and-tire combination optional. Both the 18-inch and 22-inch wheel designs have a new seven-spoke design that is specific for Cadillac models. Standard 18-inch wheels have a machine-face design, with chrome appearance available.
GMs all-new 2007 full-size SUVs are characterized by taut, athletic exterior styling with distinct design cues. The sleeker exterior designs convey strength and are aerodynamically tuned to bolster fuel economy, as well as enhance quietness.
Along with their athletic and capable presence augmented by a wider track that creates a more confident, broad-shouldered stance the new SUVs have a tailored appearance, with new, wraparound fascias and improved tolerances. The overall effect is a leaner, more refined appearance that suggests a trimmer vehicle, belying the vehicles nearly 3-inch (76.2 mm) increase in overall length.
The new SUVs represent clean-sheet approaches to design, said John Cafaro, chief designer for full-size SUVs. Each model carries the personality of its respective brand, but all share a tight, masculine design ethic that speaks to the expectations of an authentic full-size SUV one look and theres no doubt about the capabilities of these vehicles.
All major body components and sheetmetal on the 07 SUVs are new. The front-end sheetmetal differs between all models. Wraparound front and rear fascias also are new and are primary contributors to the vehicles leaner, more refined appearances. The wraparound fascias flow into the front fenders with an almost imperceptible tolerance, creating a virtually seamless appearance. Cadillac Escalade models also feature unique doors, side trim and new front fender vents that provide the vehicles unmistakable distinction.
Escalades bold styling helped enmesh the vehicle in popular culture and the new models take that boldness to a heightened level, while maintaining the iconic cues that pushed Cadillac design to the forefront of contemporary styling, said Cafaro.
A more steeply raked, 57-degree windshield gives the new SUVs the segments best overall aerodynamics of approximately 0.363 cd. The more aerodynamic profile helps reduce wind noise, as do narrowed gaps between panels and tighter, flusher mounting of the exterior components, such as the grille, headlamps and trim.
Larger standard and available wheels, including optional 20-inch wheels on Chevy and GMC models, as well as 22-inch wheels on Escalade, are tailored to fit the vehicles wheel openings. This precise wheel-to-body relationship gives the vehicle a more refined look and, with the chassis wider track, a more athletic presence.
Numerous standard and available features complement the new SUVs design, including new-design flat-blade windshield wipers and styled wiper arms, standard front tow hooks (4WD models), an available power-assisted rear liftgate, available factory-installed articulating running boards and a larger available sunroof.
Detailed cues, such as jewel-look lighting elements and doors that extend over the rockers for a smoother, more integrated side view are characteristic of the vehicles precise, refined design ethic. Highlights include:
* Wraparound front fascias
* Tighter panel and trim tolerances
* Jewel-look headlamps and taillamps
* Power-assisted rear liftgate (optional)
* Streamlined outside mirrors and roof racks
* Larger grab-style door handles
* Standard running boards with an integrated design
* Optional articulating running boards (late availability)
* Enhanced lighting performance, with standard HID headlamps on Cadillac models
* New flat-blade windshield wipers
* Ultrasonic Rear Parking Assist
* Rear-view camera
* Heated windshield washer fluid
* Larger sunroof with express open/close feature (optional)
* In-glass AM/FM radio antenna
* Streamlined roof rack styling
Chevy Tahoe design
Tahoe wears Chevys new dual-port front-end design theme, which was introduced on vehicles such as the 2006 Impala. On Tahoe, the theme is embellished with prominent borders to reflect the vehicles rugged, sporty and go-anywhere personality.
A body-color grille surround with argent-color mesh grille inserts is accented with chrome, with a prominent, gold-color Chevy bowtie in the center of the grille area. The upper and lower grille sections, along with round halogen fog lamps, are part of the integral assembly of Tahoes new, wraparound front fascia. The lower section of the fascia incorporates the front license plate holder and two recessed, integrated tow hooks. The bottom of the fasica incorporates a skid plate design cue that accents Tahoes off-road-ready appearance.
Tahoe has large, integrated headlamps that flow into the corners of the fenders. Four separate lamps are housed in round, reflective-optic pockets that are set against a darker background. This provides a floating effect that, with the attitude of the upper headlamp housings, gives the Tahoe a deep, serious face. Beneath the headlamp housings are the daytime running lamps/parking lamps. Fog lamps are standard and integrated in the lower fascia.
As with the front of the vehicle, a new fascia wraps around the rear of the vehicle for a seamless look that eliminates a large bumper-to-body gap. A gold bowtie emblem is located above the license plate pocket on a large pocket/from that also houses the components for the optional rear-view camera system (when equipped). The license plate pocket is integrated in the center of the liftgate. The liftgate can be manually operated or electrically operated when equipped with the optional power-assisted liftgate feature.
Tahoe features distinctive rear styling, highlighted by three lighting elements stacked on top of each other and mounted in a ruby-red, jewel-look housing. The lighting elements have bright trim rings. Tahoes styling also is complemented by a new family of wheels and tires, including standard 17-inch wheels and available 20-inch wheels. The new family of wheels includes available bright machine-face, polished or chrome finishes.
GMC Yukon and Yukon Denali design
Yukon and Yukon Denali models have a new, distinct appearance that introduces a new design language for GMC. The design is characterized by large, round headlamps set in vertical housings that taper at the top and wrap around into the front fenders. The round lamps a larger round lamp on the bottom with a slightly smaller lamp on top have cylindrical mounting pockets that create a detailed three-dimensional appearance when viewed through the crystal-clear lenses.
The headlamps are separated by a large grille opening that contains a prominent, red GMC logo. The two-piece grille, with chrome surround trim, includes a taller upper section, with h orizontal, dark-colored bars on Yukon and Yukon XL models. The upper section channels air to the radiator and the lower section frames the front license plate holder and the standard integrated tow hooks.
Yukon Denali and Yukon XL Denali feature an updated version of the bright grille design that makes the vehicles instantly recognizable. For the 07 models, the grille design has a more intricate mesh pattern that retains the Denali-specific chrome finish. The unique grille is accented by additional premium exterior trim cues.
The grilles of Yukon and Yukon Denali models, along with standard halogen fog lamps, are part of the integral assembly of the full wraparound front fascia systems shared among all the new SUVs. The fog lamps, like the large round headlamps, feature jewel-like optics. A molded-in, spear-shaped feature line runs across the fascia, above the fog lamps. This shape is carried by the protective bodyside moldings around the vehicle.
As with the front end, the rear of the Yukon features an integrated, wraparound fascia and unique lighting. The taillamp design includes three chrome-ringed, stacked ovals and red-color clear lenses. The three lighting elements create a concentric ring design that mimics the appearance of the round headlamps.
Distinct from the Chevy and Cadillac models, Yukon has black D-pillars with a black graphic trim piece extending from the D-pillar quarter glass to the backlight glass.
Cadillac Escalade design
The iconic design cues that made the Escalade a cultural phenomenon are enhanced with the 2007 model cues that established a new design language for all Cadillac vehicles. The 07 model also incorporates elements introduced on the landmark Sixteen concept vehicle. These elements include vertical headlamp housing with HID tri-segment lighting elements and new, stylish front fender vents.
Escalade features a more prominent Cadillac wreath-and-crest emblem in the center of the traditional shield-shaped grille. It is confidently scaled to the proportions of the bold front end styling. The grille surface is predominantly chrome, with painted elements that add texture and visual depth. It is inset with compartmentalized groups of jewel-like vents and a detailed chrome-trim liner that has a textured screen with bright edges and black sides. The overall look is more detailed, enhancing Escalades luxury aura.
Escalades new, larger HID headlamps further the vertical-design theme established by the previous-generation model, but are more prominent and feature three distinct elements. The lamps interior parabolas are highly reflective and contribute to the jeweled looked when viewed through the crystal-clear lenses. The Cadillac logo is etched into the bulb shields, which contain new HID lighting elements.
The Escalade has a unique, wraparound front fascia that creates a seamless appearance. The lower portion of the fascia incorporates recessed, integrated tow hooks, owing to the Escalades primary mission as a capable full-size SUV. In true Escalade fashion, the tow hook openings make a stylish design statement.
The new front fascia flows smoothly into the front fenders, which are distinguished with Escalade-exclusive front fender vents. The vents, located at the top-rear corner of the fenders deliver a detailed appearance, with three sections set off by a chrome top bar and chrome surround trim. The vents add visual distinction to the Escalade lineup and are sure to become signature hallmarks, like the vertical headlamps and prominent wreath-and-crest grille emblem.
As with the front end, Escalade models have a specific wraparound rear fascia. The license plate holder is integrated into the liftgate and a prominent wreath-and-crest emblem is mounted above it. The fascia also incorporates sensors for the standard Ultrasonic Rear Parking Assist feature, as well as the standard trailer hitch platform. The platform is covered to maintain Escalades tailored appearance, but is easily removable.
Escalades vertical lighting theme also is carried to the rear of the vehicle, with two arrays of elegant LED-lit taillamps. The lamps feature indirect optics and numerous sources of illumination per unit, which provides a broader, more even lighting display and eliminates the pinpoints of light normally associated with LEDs.
As part of its bold, powerful appearance, Escalade offers optional 22-inch wheels and tires the largest factory-installed wheels in the full-size segment. All Escalade models including those equipped with the standard 18-inch wheels and tires feature a unique seven-spoke wheel design.
Aerodynamics and wind noise reduction
GMs new full-size SUVs are the most aerodynamic in the segment with a 0.363 coefficient of drag. The more aerodynamic shape enhances fuel efficiency and quietness.
Contributors to the SUVs aerodynamic efficiency include:
* Front air dam Carefully integrated stylish wraps into the leading edge of the tires. Compared to previous models, it is lower and wider.
* Tighter tolerances New fascia designs, headlamp and grille mounting, and trim mounting attention to detail improve or eliminate gaps and improve tolerances compared to previous models, reducing drag.
* Improved sealing Airflow into the grille is more efficient with improved front-end sealing, which almost eliminates air leak paths that can create drag.
* Streamlined components Exterior components such as the rear-view mirrors, running boards and roof rack are aerodynamically tuned for reduced drag and noise. The high-mounted stop lamp (also known as the CHMSL) also is aerodynamically tuned, located in a housing that extends nearly the entire width of the roof, with the Cadillac Escalades sharp-edged CHMSL offering the most aerodynamic aid of all the new SUVs lamps.
Improved aerodynamics help enhance driving quietness, as do numerous body sealing features designed to reduce wind noise including new-design door-to-body seals. The primary door seal has a sculpted shape with multiple internal chambers in the material that condense to provide a tighter fit when the door is closed. An auxiliary door seal, which runs from the lower A-pillar to the top of the doorframe and around the second-row door opening, has a combination of soft and stiff rubber material to prevent movement during driving. This helps maintain a constant seal, virtually eliminating the sound of wind noise as the vehicle speed increases.
Tighter tolerances
All models feature a one-piece, body-color front fascia that wraps around into the front wheel openings, creating a sleeker, more integrated appearance. The fascia covers the front bumper beam, eliminating the conventional look of a bumper separated from other body components. This more seamless design is one of the many details that helps improve aerodynamics and reduce wind noise. Hood-to-fender gaps are reduced, as are the headlamp-to-fender gaps.
At the rear of the vehicles, gaps are reduced around the liftgate and fascia top that creates a refined and precise appearance The liftgate-to-quarter panel and liftgate-to-taillamp tolerances have also been reduced with a new, one-piece door ring, or D-ring. The D-ring provides an extremely strong, dimensionally accurate foundation for details like the taillamp mounting holes. The quarter panels, underbody and roof all are welded to the D-ring in the upper body structure, which enables the precise fit and enhances the tight structure of the vehicles.
From the side, all models have a more integrated appearance, with t he increased windshield angle helping create a smoother transition to the roofline. The streamlined look is accented with smoother, lower-profile roof racks.
Doors extend down and wrap over the rockers for a cleaner, one-piece appearance and improved bodyside integration. The Cadillac Escalade features different door designs and window moldings that fit the contours of the unique front-end styling. Badging on all models consists of simple, element chrome letters on the front doors and liftgate. All models feature discreet GM Mark of Excellence insignias located on the forward edge of the front doors.
Rear-view mirrors are styled for improved aerodynamics and reduced wind noise. All model feature new, refined grab-style door handles that are designed to stand off from the edge of the vehicle for easier actuation. Door closing is effortless and quiet.
Standard running boards are integrated with the exterior design themes and optional power articulating running boards (available later in the model year) automatically extend when the doors are opened. When not in use, the boards retract inward, giving the vehicle a sleeker, more refined appearance.
Power liftgate
A new power liftgate is available on most models. The liftgate can be remotely opened, regardless of whether the vehicle is locked, by pressing and holding a key fob button for one second. Pressing and holding the key fob button closes the liftgate. If the vehicle is locked, the gate also locks. A second activation switch is located in the overhead console. A third control button on the liftgate itself will also automatically close the gate, after the vehicle is loaded.
Vehicles not equipped with the power liftgate feature an electric liftgate release feature. The liftgate has a pull handle with a micro-switch release. It allows the electrically operated liftgate latches to be released in an easy, one-touch manner by simply pressing the pull handles release pad.
The glass in the liftgate also has an easy access release switch. A pull strap and pull cup on the inside trim allow operators to close the liftgate, without having to grab the outside of the gate.
Larger power sunroof
A power-operated sunroof is available on the 2007 full-size SUVs and is larger than previous models. It is approximately 2 inches (50.8 mm) wider, allowing for a greater open-air driving feel. The sunroof also has a new express open/close feature and pop-up wind deflector that helps reduce wind noise with the sunroof is open.
Windshield wipers and heated washer fluid
New, flat-blade windshield wipers, which are pre-formed to contour the curvature of the windshield glass, provide more uniform pressure on the windshield glass to enhance clearing, minimize streaking and nearly eliminate wind noise. The blades are mounted on stylish arms that have less structure than previous-design models, eliminating joint and other points that can freeze, bind or cause chatter.
Rain-sensing wiper activation is available on some models (standard on Escalade), which automatically turns on the wipers when precipitation is detected. The system also automatically varies the wiper speed depending on the amount of precipitation. An infrared sensor mounted near the top of the windshield (behind the inside rear-view mirror), determines when precipitation on the windshield is sufficient to warrant turning on the wipers.
A heated windshield washer fluid feature also is available on some models (standard on Escalade). The heated fluid provides improved and faster clearing of frost and light ice buildup, as well as enhanced insect cleaning capability.
Regular washer fluid operation is available with the standard stalk-mounted control, while the heated fluid is available via an instrument panel control. When activated, regular washer fluid is diverted to a reservoir, where it is briefly super-heated to up to 140 degrees F. The system provides enough heated fluid for four cycles of use.
Ultrasonic Rear Parking Assist
The new optional Ultrasonic Rear Parking Assist system provides visual and audible warnings of objects behind the vehicle. The system operates when the vehicle is in Reverse, using four sensors located at the rear of the vehicle. The new system is available with a new, optional rear-view camera system, the first offered in a GM vehicle.
Rear-view camera system
The rear-view camera system is available with the optional navigation radio system. The camera provides a view of the rear of the vehicle not easily seen, even with the outside or inside rearview mirrors, allowing the driver to check for persons or obstacles directly in the path of the vehicle. It also assists with parallel parking or trailer backing. Drivers should still inspect around their vehicle for objects or playing children.
A large, clear picture of the cameras field of view is available on the navigation radio screen. The rear-view camera also works with the Ultrasonic Rear Parking Assist to provide an audible proximity reference to items in the cameras view. If an RPA sensor detects a person or object, it alerts the camera.
The camera only functions when the vehicle is shifted into Reverse. For convenience, it will stay on for a calibrated length of time determined partly by vehicle speed after the vehicle is shifted into Drive. The camera is mounted in the license plate surround bracket for an integrated styling appearance. It provides approximately 20 feet (6.1 meters) of viewing distance behind the vehicle.
GMs 2007 full-size SUVs have inviting new interiors that are quieter, more spacious and comfortable, with heightened refinement throughout their environments.
Like the exterior styling that envelops them, the all-new interiors have greater brand distinction than any previous generation, with each model highlighting characteristics that embody its brand. Unique cluster facings, graphics, wood and metal accents, steering wheels and color schemes are the distinguishing brand identifiers inside. All models benefit from the use of premium materials, chrome accents, and soft touch surfaces with low gloss levels, as a high level of refinement and quality craftsmanship is standard equipment across all brands.
Cadillac Escalade models have an exclusive luxury interior, befitting the king of luxury SUVs. Escalades specific design includes a unique instrument panel, door panels, seats, instrumentation and center console. Escalade also receives enhanced premium materials and features, such as foam-backed cast skin covering for the instrument panel, upper door trim and armrests, unique instrument lighting, fabric-covered interior pillars, available heated and cooled front seats, available heated steering wheel and a DVD entertainment system with flip-down screens for the second- and third-row occupants.
All 07 full-size SUVs are roomier and more comfortable, with greater passenger space and cargo carrying capacity. Instrument panels that are positioned lower and further forward add to the feeling of spaciousness, as well as improve outward visibility. There are new comfort features such as best-in-class cabin quietness and new, highly styled and supportive seats. Unique features, such as the innovative easy use power fold-and-tumble rear seat eases access to the third-row seat.
These are the most refined and luxurious SUV interiors, period, said Gary White, General Motors North America vice president and vehicle line executive for full-size trucks. The passenger environments represent GMs drive to produce the quietest, most finely crafted interiors in the segment.
Refinement and craftsmanship
The perceptual quality of the new full-size SUV interiors far surpasses any previous generation. It results from the close attention to details engineered into every facet of the cabin and is highlighted by flush surfaces, tight gaps and tolerances on the instrument panel, center stack, clusters and other components.
Most gaps on the instrument panel and cluster have been narrowed to 0.5 mm or less. Some gaps have been totally eliminated. Flush-mounted accessories and controls, such as the climate control/radio center stack create a seamless, more finished appearance appearing as a single unit rather than components stacked together.
Similar attention was given to concealing fasteners and metal structural components of all folding seats. New seat close-outs provide a more finished, crafted appearance to the seats when they are in a folded or tumbled forward position. The seat tracks also are concealed with covers.
The two-tone interior color scheme, executed with rich, warm colors, dramatically enhances the appearance and aura of the new SUVs interiors. The upscale styling is complemented by new, soft-touch and low-gloss finishes for the instrument panel and other trim pieces. Also, the color and grain of materials were carefully selected to provide a premium look. Upscale details also include LED backlighting for instrumentation and chrome accents on gauges and vents. The comprehensive result of these elements is a rich, harmonious appearance throughout the interior.
More expansive feel
An enhanced feeling of spaciousness is immediately apparent when seated in the all-new 07 SUVs. This is due to the repositioned instrument panel that, compared to the previous-generation SUVs, is moved forward and down 5.75 inches (146 mm). Also, a faster windshield rake of 57 degrees (vs. the previous models 50 degrees) helps create an airy, panoramic view.
GMs new SUVs also deliver more passenger space and room to stretch, as well as seating rows designed for easier entry and egress. The front seats offer 1 inch (25.4 mm) of increased rearward travel and the second-row seats offer 0.4-inch (10 mm) increased legroom: 39 inches (990.8 mm). Also, the second-row seatback angle is increased from 23 degrees to 25 degrees, which enhances seat comfort.
Engineers also were able to provide slightly more shoulder room for first- and second-row passengers while packaging the roof-mounted head curtain side air bags. To provide more generous third-row shoulder room, the seats hip point was moved slightly forward and upward. Third-row headroom also is increased to 37.9 inches (963.5 mm) 0.6-inch (15.2 mm) more than before. The seating position of the third-row seats enhances outward visibility, too.
Cargo room of the Chevy Tahoe, GMC Yukon/Yukon Denali and Cadillac Escalade has increased by 4.2 cubic feet (118.9 liters) behind the second row seats and 2.3 cubic feet (65.1 liters) behind the third row.
Enhanced comfort
Seating comfort for the SUVs, which was already the best in the segment, is enhanced with new, European-style seats that are slimmer and more comfortable than previous models. The seats have a tailored appearance, with double-stitched French seams, and are more supportive, with firmer foams and more supportive side bolsters. The streamlined look also comes from anchoring the outboard safety belts of first- and second-row seats to the vehicles pillars.
Heated first- and second-row seats on both bench and bucket seats are available. Cadillac Escalade also offers heated and cooled front seats that feature perforated leather designed to enhance airflow. Additional comfort-enhancing features include second-row armrests that are curved to match the contour of the seatback and longer armrests for all bucket seats. Also, the third-row seats offer integrated storage bins and cup holders.
Another first is third-row seating available in two- or three-passenger configurations. In fact, all three seating rows of the Chevy Tahoe and GMC Yukon/Yukon Denali are offered in two- or three-passenger configurations; Cadillac Escalade comes with two front bucket seats. A variety of cloth and leather-covered seating surfaces are available on Tahoe and Yukon ; leather is standard on Yukon Denali and Escalade. All cloth seats us heavy-duty fabric with double-stitched French seams; durable, high-wear Meridian leather is used on Tahoe and Yukon . Nuance leather is used on Escalade and Denali seating surfaces.
Interior details and convenience features
All models offer distinct interior styling, appointments and features, including the Escalade models unique instrument panel/seating/center console configurations. Highlights for all models include:
* New, streamlined European-styled seats with tailored appearance designed for increased support and comfort
* Increased front seat travel
* First- and second-row outboard safety belts mounted to door pillars
* Second-row seats moved rearward for increased legroom and seatback angle increased for more comfort
* Available first- and second-row seat heating
* Third-row seating with increased headroom and improved outward visibility
* Available two- or three-passenger third-row seating
* Increased shoulder room on first- and second-row seats, with roof-mounted head curtain side air bags
* Finished seat close-outs that conceal seat hardware
* Innovative fold-and-tumble second-row seat
* Standard tri-zone manual climate control (Tahoe and Yukon ); tri-zone automatic climate control standard on Yukon Denali and Escalade, and available on Tahoe and Yukon
* Revised HVAC system with single-button front-seat control for rear passengers
* Increased cargo room behind second- and third-row seats, along with new storage bins and cup holders attached to third-row seats
* New center console design with segments largest storage capacity of more than 20 liters (0.7 cu. ft.)
* 25-percent larger glove box with spring-damped opening feature
* Available power-assisted rear liftgate
* Available heated windshield washer fluid
* Larger available sunroof with express open/close feature
* Available power-adjustable pedals
Cadillac Escalade adds additional luxury and convenience features, including:
* Unique instrument panel and center console design
* Premium soft instrument panel and interior trim materials, including Meridian leather covering
* White-LED continuously backlit gauges
* Available heated and cooled front seats with perforated leather-covered seating surfaces
* Unique steering wheel design with premium wood trim options
* Available heated steering wheel
* Rear-seat entertainment system with second-row and third-row DVD screens available
Power fold-and-tumble second-row seat
New for the 07 SUVs are second- and third-row seats that fold and tumble for easier third-row entry and egress. The second-row features an industry-exclusive power fold-and-tumble feature, which remotely unlatches the seat to send it into its forward-folded and tumbled position. This greatly eases access to the third seating row, while also easing the burden of parent holding a child there is no need to fumble with both hands to release and fold the seat forward.
The power fold-and-tumble feature operates with the press of a button from the first-row overhead console or door pillar. The button activates a release mechanism on the seat latch, allowing the seat to fold forward into the tumbled position. (The seat must be returned to the original seating position by hand.)
Also adding convenience to seating and storage options are the SUVs easily configurable and removable third-row seats. The seatbacks fold flat to create a convenient load platform. They also can be removed quickly to create additional storage space. Two easy-to-operate levers on the seatback allow the seats to be quickly removed.
Cargo room and new power liftgate
The 07 models of the Tahoe, Yukon/Yukon Denali and Escalade offer increased cargo room of 4.2 cubic feet (118.9 liters) more behind the second row seats and 2.3 cubic feet (65.1 liters) more behind the third row. This gives the vehicles a cargo capacity of 108.9 cubic feet (3,084 liters) when the second-row seat is folded and tumbled forward and the third-row seat is removed. There also is 60.3 cubic feet (1,707.7 liters) of cargo space with the second row seat in place and the third-row seats removed. There is 16.9 cubic feet (478.6 liters) of cargo space behind the third-row seats.
The significant increase in cargo capacity is achieved in vehicles that have grown in length by only approximately 3 inches (76.2 mm). Engineers found the additional room by streamlining the cargo area with relocated and flush-mounted air conditioning ducts and slimmer liftgate trim.
Along with cargo volume, the new SUVs have the capability to carry 4 x 8-foot sheets of plywood and even wider T111 tongue-and-groove paneling without removing the rear seats. This is accomplished by simply folding and tumbling the second-row seat forward and folding the third-row seat flat.
A new, power-assisted rear liftgate is available and is a first for any GM SUV. The gate can be operated with the key fob remote or with controls located inside the vehicle. The liftgate opens with a single push of the button, easing the burden of fumbling for keys and manual operating the liftgate with arms full of groceries or children. Closing the liftgate simply requires another push of the button.
Storage options and convenience features
The all-new interior designs of the 07 SUVs include (on vehicles equipped with front bucket seats) large center consoles with the segments largest storage capacity 0.7 cubic foot (20.1 liters) of undivided volume. Instead of running up and over the center stack, the console flows beneath it, narrowing the gaps to the instrument panel and maximizing storage space.
A leather-like, soft-covered console lid on the Chevrolet and GMC models adds to the vehicles premium feel while functioning as an armrest for both front passengers. When opened, the lid reveals the storage compartments many features, including a power point suitable for charging cell phones while they are discreetly stored and flocking that can prevent items from moving or rattling. At the front of the console are two cup holders, which can be repositioned or removed altogether. The rear of the console houses two cup holders for second-row passengers, along with air conditioning vents and a power point that can be used for video input, handheld games and rear seat audio controls.
Cadillac Escalade features a dual-opening console lid, with a soft, leather-like cover. A wood trim appliqué adds distinction and matches the Northern engraving wood trim found elsewhere in the interior. The wood trim runs through the center of the console, providing a sense of compartmentalization.
The Escalades console opens with a chrome, spring-damped release button that fosters the vehicles refined nature. Multilevel storage within the console includes a smaller, contained space for delicate items like sunglasses. Releasing the second lid opens up the consoles large storage compartment. Additional premium features include separate front compartments, including one with a 12-volt power source. At the rear of the Escalades console are two, chrome-ringed cup holders for second-row passengers.
Chevrolet and GMC vehicles equipped with a front 40/20/40-split bench seat feature a large fold-down center section when a passenger isnt occupying the center seat position that provides two cup holders and a large, deep storage bin suitable for holding a lunch bag.
The new SUVs glove boxes have 25 percent more storage capacity as well as a single-bin configuration. The glove box capacity is 0.18 cubic foot (5 liters) and the lid is spring-damped, which provides a quiet, high-quality feel when opening or closing the glove box. Additional storage comes from front- and rear-door map pockets, as well as front seatback compartments that are large enough to store a road atlas.
Climate control system
Chevy Tahoe/Suburban and GMC Yukon/Yukon XL have standard manual-control tri-zone climate control. Automatic tri-zone climate control is available on Chevrolet and Yukon models, and standard on Yukon Denali and Cadillac Escalade models. Engineers enhanced the tri-zone systems to provide quieter operation, more efficient cooling and airflow for second- and third-row passengers, and improved side-window defogging.
The tri-zone systems also feature new controls that simplify operation, including one-button control for the automatic system that controls rear air conditioning. And, as with previous systems, the 07 SUVs climate systems continue to allow up to 30-degree F difference in temperature setting between the driver and front passenger, as well as separate controls for rear-seat passengers.
Heated windshield wiper fluid
Another first for GM SUVs is the optional heated windshield washer fluid system, which more effectively removes bug spatter and thin layers of ice and frost. The fluid is heated up to 140 degrees F (60 C).
The heated fluid is used when activated by a special button on the instrument panel; ambient temperature fluid is used when the driver selects the standard washer system on the control stalk. When the heated system is activated, washer fluid is directed to a special reservoir and super heated very quickly for approximately 20 seconds. Enough fluid enters the reservoir to accommodate four cycles of windshield cleaning.
Larger power sunroof
A larger, power-operated sunroof is available on the 2007 full-size SUVs. It is approximately 2 inches (50.8 mm) wider, allowing for a greater open-air driving feel. The sunroof also has a new express open/close feature and pop-up wind deflector that helps reduce wind noise with the sunroof is open.
Adjustable pedals, rear-view camera and Ultrasonic Rear Parking Assist
Features including Ultrasonic Rear Parking Assist, rear-view camera system and power-adjustable pedals are available on most models (some features not available on base models). Yukon Denali and Escalade models offer additional comfort and convenience features, including an optional heated steering wheel.
Ultrasonic Rear Parking Assist provides visual and audible warnings of objects behind the vehicle. Similarly, the optional rear-view camera system (requires optional navigation radio system) provides a visual reference for the rear of vehicle and works with the Ultrasonic Rear Parking Assist to provide assistance for maneuvers such as backing a trailer. (More information on the Ultrasonic Rear Parking Assist and rear-view camera systems is available in the Safety and Security section.)
The power-adjustable pedals help ensure a comfortable and safe driving position for almost every-sized driver. At the push of a button, the pedals move on an angle upward to meet the leg length of smaller-stature drivers.
A new generation of GMs legendary small-block V-8 engine is the power behind GMs all-new full-size SUVs, delivering increased performance and fuel economy through advanced technology such as Displacement On Demand and variable valve timing.
The Gen IV small-block Vortec V-8 engine family including the 5.3L V-8 is standard in all models, with displacements ranging from 4.8L to 6.2L, and estimated horsepower ranging from 290 horsepower (216 kw) to 400 horsepower (298 kw).* The engines are backed by proven Hydra-Matic electronically controlled automatic transmissions, including a new 6L80 six-speed.
The new Vortec engines represent the fourth generation of the small-block V-8, which debuted in 1955. Highlights include:
* Revised cylinder block design with externally mounted knock sensors
* High flow cylinder heads on 6.0L and 6.2L engines
* Variable valve timing on 6.0L and 6.2L engines
* Displacement On Demand on 5.3L and aluminum-block 6.0L engines
* Electronic throttle control
* 58X ignition system
* New, more powerful E38 32-bit controller
* Enhanced quietness and smoothness
* Returnless fuel system
* E85 fuel capability on some 5.3L engines
* Stringent validation and durability testing throughout development process
The Vortec Gen IV V-8 family delivers balanced performance and efficiency through technical innovation, said Christopher Meagher, assistant chief engineer. Fuel-saving features, such as Displacement On Demand, affirms the small-block V-8s leadership role in trucks.
Supporting the high-performance capability of the 6.2L engine is the new Hydra-Matic 6L80 six-speed automatic transmission. It has a wide, 6.04:1 overall ratio including two overdrive gears that helps deliver an excellent balance of performance and fuel economy. It is similar to the six-speed paddle shift automatic transmission introduced on the 2006 Corvette, but is been tailored for the heavy-duty requirements of SUVs and trucks.
There are no compromises with the 6L80 transmission it delivers great performance and enables improved fuel economy on the highway, all with smooth, almost imperceptible operation, said Jeff Baran, chief engineer for six-speed rear-wheel drive transmissions.
The 6L80s six forward gears have smaller steps between them, compared to a conventional four-speed automatic, which bolsters both performance and the feeling of smoothness. Shorter steps between the gears help the transmission quickly find the best gear for the vehicle speed and road conditions, with less back-and-forth hunting on grades a trait that is particularly helpful when towing.
Gen IV small-block details
The Gen IV Vortec V-8 truck engines are built in a variety displacement and power combinations, including versions with aluminum cylinder blocks. All engines share a basic architecture that includes 4.400-inch bore centers the same design foundation on which the original small-block V-8 was developed in the early 1950s. Initial Gen IV engine offerings include:
* 4.8L iron block (RPO LY2), rated at 290 horsepower (216 kw)*
* 5.3L iron block (RPO LY5) with Displacement On Demand technology, rated at 320 horsepower (238 kw)* including E85-capable version (RPO LMG)
* 5.3L aluminum block (RPO LC9) with Displacement On Demand technology and E85 capability, rated at 320 horsepower (238 kw)*
* 6.0L iron block (LY6) heavy-duty engine with variable valve timing, rated at 350 horsepower (261 kw)*
* 6.0L aluminum block (L76) with Displacement On Demand technology and variable valve timing, rated at 355 horsepower (264 kw)*
* 6.2L aluminum block (L92) with variable valve timing, capable of 380 to 400 horsepower (283 to 298 kw)*
All Gen IV Vortec engines are designed to provide improved fuel economy and reduced emissions, compared to previous-generation small-block V-8s. The 5.3L engines with Displacement On Demand (DOD) technology, for example, provide up to seven percent fuel economy gains.
The new engines also meet more stringent emissions standards. In fact, compared to truck engines of a decade ago, the Gen IV Vortec engine family is approximately 90 percent cleaner. Cast iron exhaust manifolds matched with dual close-coupled catalytic converters help reduce cold-start emissions, which is the largest source of vehicle emissions.
Revised cylinder block
Aluminum-block Gen IV-design engines debuted as the LS2 in the 2005 Chevy Corvette and SSR, as well as the 05 Pontiac GTO. The new Vortec truck engines share the basic design of these versions, but are engineered for the specialized needs of truck applications. Like the LS2, the new Vortec engines have a revised cylinder block design that features new, externally mounted knock sensors. They were moved from the valley area to enable Displacement On Demand technology and other advanced systems.
Some Gen IV Vortec engines use aluminum cylinder blocks, which offer reduced mass an attribute that supports improved vehicle weight distribution and slightly improved fuel economy. The aluminum blocks are virtually identical to their iron counterparts, including a deep skirt design that incorporates cross-bolted main bearing caps and a structural oil pan. All engines, except the 6.2L L92, use a proven iron crankshaft design and highly durable reciprocating components. The high-performance 6.2L L92 uses a forged steel crankshaft.
The block for the 6.2L engine features a crankcase windows vents that help improve bay-to-bay breathing. This reduces pumping losses and supports the high horsepower output of the high-performance engine. A new, 58X ignition system and a more powerful, E38 ECM are integrated on all engines.
The 58X ignition system uses a unique crankshaft wheel and sensors to provide the new, 32-bit E38 ECM with more immediate information on the crankshafts position during rotation. In turn, this allows the controller to adjust ignition timing with greater precision, which optimizes performance and economy. Engine starting also is more consistent.
Displacement On Demand (DOD)
Some 5.3L and 6.0L engines are equipped with GMs fuel-saving Displacement On Demand technology, which can temporarily shut down the combustion process of half the engines cylinders under certain driving conditions to save fuel. GM was the first manufacturer to offer this fuel-saving technology on trucks. On the new full-size SUVs, it works with other attributes, such as improved vehicle aerodynamics, to maintain GMs fuel economy leadership in the segment.
A sophisticated engine controller determines when to deactivate cylinders, allowing the engine to maintain vehicle speed in lighter-load conditions such as highway cruising. The process is seamless and virtually imperceptible. When the cylinders are deactivated the engine effectively operates as a V-4, with alternate cylinders on each cylinder bank disabled. The engine returns to V-8 mode the instant the controller determines the vehicle speed or load requires additional power. The key to DODs efficiency and virtually imperceptible operation is a set of special two-stage hydraulic valve lifters, which allows the lifters of deactivated cylinders to operate without actuating the valves.
The valve lifters have inner and outer bodies, which normally operate as a single unit. When the engine controller determines cylinder deactivation conditions are optimal, the outer body moves independently of the inner body on the disabled cylinders lifters. The outer body moves in conjunction with camshaft actuation, but the inner body does not move, holding the pushrod in place. This prevents the pushrod from actuating the valve, thereby halting the combustion process. Solenoids in the engine lifter valley operate to deliver high-pressure oil to the switching lifters, activating a release pin to separate the inner and outer bodies. Oil circulation and pressure do not vary, regardless of the engines operational mode. Lifter design and pushrod length are the same for every cylinder, but camshaft lobe profiles differ for cylinders designated to be deactivated.
The engines electronic throttle control (ETC) also is used to increase manifold pressure in V-4 mode so that the engine can maintain a V-8 torque load.
Variable valve timing (VVT)
Variable valve timing (VVT) is a standard feature on 6.0L and 6.2L engines; it helps optimize camshaft timing to improve low-rpm torque and high-rpm horsepower. The introduction of variable valve timing through the unique dual-equal cam phaser is the industrys first application of VVT on a mass-produced V-8 cam-in-block engine. The unique dual-equal phaser adjusts the camshaft timing at the same rate for both the intake and exhaust valves.
The system incorporates a vane-type camshaft phaser that changes the angular orientation of the camshaft, thereby adjusting the timing of the intake and exhaust valves to optimize performance and economy, and help lower emissions. It offers infinitely variable valve timing in relation to the crankshaft. The cam phaser vane is attached to the camshaft on the front journal. As driving conditions warrant, the cam phaser system can reduce ignition timing at higher rpm levels to increase power. At lower rpm levels, torque is enhanced with increased timing.
This cam phaser feature was pioneered by GM and introduced on the new 3.5L and 3.9L V-6 engines in 2005 a first for the use of variable valve timing on a cam-in-block engine design. As driving conditions warrant, the cam phasing system can reduce ignition timing at higher rpm levels to increase power. At lower rpm levels, torque is enhanced with increased timing.
Precise camshaft timing is the key to the variable valve timing systems capability to optimize performance. Like the 58X ignition system, cam phasing is directed by the E38 ECM. It relies on data from a camshaft position sensor a target ring with four equally spaced segments that communicates the camshafts position quicker and more accurately than previous systems that used just a single segment. Also, a leaf spring-type tensioner is used on the timing chain to ensure precise tension.
The aluminum-block 6.0L version uses variable valve timing in conjunction with Displacement On Demand technology to bolster fuel economy. With cam phasing, Displacement On Demand technology allows the engine to run longer in fuel-saving four-cylinder mode, while producing instant V-8 power and response as soon as the driver calls for it.
High-flow cylinder heads
The Vortec 6.0L and 6.2L engines offer a significant power level increase compared with previous premium engines, with much of the newfound power coming from high-flow aluminum cylinder heads. The heads are based on the racing-derived cylinder heads of the Corvette Z06s LS7 7.0L engine, including a unique inlet port shape and offset rocker arm design. Airflow of the heads is supported by large 55-mm-diameter intake valves and 40.4-mm-diamter exhaust valves.
The heads use the high-performance technology of the Corvettes LS7 to build efficient power in truck engines, said Meagher.
Vortec 4.8L and 5.3L engines also have high-flow, Corvette-derived heads. They are based on the previous-generation Corvette Z06s LS6 engines cylinder heads and have flow characteristics commensurate with the engines airflow-to-displacement needs. All the Gen IV Vortec engine variants use the same efficient ignition coil packs of the LS2 to light off the air/fuel mixtures that are drawn through the heads.
Quiet, durable operation
All Gen IV small-block Vortec V-8 engines are designed for quieter operation, including:
* Special friction-reducing coating on piston skirts
* Full floating piston pins
* Damping patch on the oil pan (externally mounted)
* Timing chain tensioner
* Quieter alternator
The quiet features of the engines are complemented in the vehicles with stronger engine cradles and mounting systems. These systems help reduce vibrations transmitted through the chassis and would otherwise be felt by vehicle passengers.
Backing the new engines quietness is the assurance of long-lasting performance. The new Gen IV engines were validated under extreme conditions, with dynamometer testing equivalent to 150,000 miles. The Vortec 6.0L iron block heavy-duty engine was tested the equivalent of 200,000 miles.
Some of the stringent durability testing included cycling engines between the peak torque and peak horsepower rpm points the equivalent of towing a heavy trailer up a steep grade for 600 straight hours.
The engines also feature many long-life engine components that can reduce maintenance intervals and costs. The iridium-tip spark plugs, engine coolant, accessory drive belt and sealing gaskets are some of these items. Also, a revised water pump design (introduced on late Gen III V-8s) has improved sealing for increased durability.
E85 capability
Two versions of the Vortec 5.3L Gen IV V-8 are compatible with E85 ethanol-based fuel, which offers a good environmental alternative to gasoline. The engines can run on any combination of gasoline and/or E85 fuel.
A new virtual fuel sensor reduces the cost and complexity of adding E85 capability to the fuel system. The ECM samples the exhaust at the oxygen sensor, and an algorithm determines whether E85 is used, as well as its mixture percentage with gasoline. Its a much simpler, less costly system than previous systems that relied on fuel composition sensors. In fact, the entire system on the engine is simple: only the fuel rail and fuel injectors are different between E85 versions and non-E85 versions.
E85 is a clean-burning alternative fuel made in the United States with homegrown corn and other crops. E85 is largely alcohol, composed of 85 percent ethanol and 15 percent gasoline. The alcohol is produced by fermenting plant sugars. E85 nearly eliminates greenhouse gas emissions from automobiles, is biodegradable, doesnt contaminate the water supply and can be produced from various feed stocks, including grain, corn and wheat stalks, forestry and agricultural waste, and even municipal waste.
Hydra-Matic 6L80 details
GMs new, Hydra-Matic 6L80 electronically controlled six-speed automatic transmission is matched with the 6.2L engine. A higher-capacity Hydra-Matic 4L70-E four-speed automatic is paired with 6.0L engines; 4.8L and 5.3L powertrains are teamed with the Hydra-Matic 4L60-E four-speed.
The 6L80s wide, 6.04:1 overall ratio, including two overdrive gears, allows for the transmissions shorter steps between gears. This enables a steep, 4.02:1 first gear, which provides a very strong launch feel. The two overdrive gears include a 0.85:1 ratio in fifth gear and a 0.67:1 ratio in sixth. With two overdrive gears, engine rpm is reduced by approximately 9 percent at 60 mph a reduction of about 1,350 rpm. Lower engine rpm can bolster fuel economy because less fuel is used. A lower-rpm cruising speed also enhances smoothness and reduces noise heard in the vehicles cabin.
Technical sophistication is exemplified by clutch to clutch operation that reduces complexity and packaging. It also enhances the performance feel of the transmission, as shifts feel more immediate and precise. Clutch to clutch operation is achieved with three planetary gears, three stationary clutches and two rotating clutches. It is a simple, less complex design that enables the six-speed transmission to be packaged in a size not much larger than a four-speed automatic. All forward gear shifts feature clutch to clutch operation.
A new, 32-bit electro-hydraulic control module optimizes the 6L80s performance according to a variety of vehicle inputs, while also enabling features including tow/haul mode, auto grade braking and manual range selection. The controller is integrated within the transmission.
Tow/haul mode is a driver-selectable feature that reduces shift busyness when towing or hauling a heavy load. The feature is complemented by manual range selection or tap-up/tap-down capability which allows the driver to manually select upshifts and downshifts with a button on the column shifter. Auto grade braking is available when the tow/haul mode is selected and the transmission is not in the range selection mode.
*Preliminary, pending certification. A new voluntary power and torque certification procedure developed by the SAE Engine Test Code committee was approved March 31, 2005 . This procedure (J2723) ensures fair, accurate ratings for horsepower and torque by allowing manufacturers to certify their engines through third-party witness testing. GM was the first auto manufacturer to begin using the procedure and expects to use it for all newly rated engines in the future.
* Compatibility brackets protect lower-riding vehicles in crashes
* Safety belt pretensions that activate in rear impact are industry first
* Roof-mounted head curtain side air bags add rollover protection
GMs new 2007 full-size SUVs are designed to be among the industrys safest and most secure vehicles. The vehicles provide a 360-degree perimeter of safety protection and provide increased compatibility with other vehicles.
New features include available roof-mounted head curtain side air bags, which are integrated into strengthened chassis and body structures to provide excellent passenger protection. Stabilitrak electronic stability control with rollover mitigation technology is standard.
These vehicles envelop occupants with a comprehensive safety system that is built from a foundation of segment leadership in safety technology said Gary White, General Motors North America vice president and vehicle line executive for full-size trucks.
GMs full-size SUVs have a heritage of safety innovation. Previous-generation vehicles were the first vehicles in the industry to offer a passenger sensing system to suppress deployment of the front passenger air bag if a child or person of smaller stature is detected. GMs full-size SUVs also were first to offer dual-stage air bags, standard four-wheel antilock brakes and a standard electronic stability control system.
In the new models, comprehensive safety encompasses crash avoidance, occupant protection and post-crash care. The safety portfolio features three linked avenues of protection: vehicle structure and dynamics; occupant safety features, and driver control features.
It starts with a stronger frame and body structure. Crash avoidance, for example, is bolstered through enhanced driver control dynamics, such as wider front and rear tracks, as well as more responsive suspensions including a new coil-over-strut front suspension design and new rack-and-pinion steering. StabiliTrak electronic stability control with roll-over mitigation is standard on all models.
Here are the safety highlights of GMs 2007 full-size SUVs:
1. Vehicle structural and safety dynamics :
* Body-on-Frame (BOF) structure with comprehensive use of high-strength steel
* Stronger, stiffer frame, including all-new front bay design for improved crush dynamics and provisions for improved vehicle-to-vehicle compatibility
* Wider front and rear tracks enhance stability, handling and lower the center of gravity
* Enhanced body structure for superior occupant protection
1. Occupant safety and security :
* Standard dual-stage drivers front air bag and dual-stage outboard-front passenger air bag with passenger occupant detection system
* Available roof-mounted head curtain side air bags with tethers and roll-over protection for all seating rows
* Front safety belt pretensioners
* A 360-degree sensing system for fast, accurate impact analysis and airbag deployment/seatbelt pretensioner activation
* Enhanced head-impact protection
* High-retention front seatbacks help restrain front seat passengers during a collision
* Three-point safety belts in all seating positions (except base vehicle front bench center seat position)
2. Driver control :
* Enhanced driving dynamics, including standard StabiliTrak electronic stability control with rollover mitigation
* Autotrac active transfer case
* Larger-capacity four-wheel disc brake system
* Standard door child security locks
* Standard four-channel ABS and traction control
* Standard tire pressure monitoring system
* Standard Passkey III anti-theft system
* OnStar system Gen 6
* Available locking rear differential
* Available Ultrasonic Rear Parking Assist
* Available rear-view camera system
* Available remote start capability
* Available rain-sensing wiper system
Vehicle structural and safety dynamics
The vehicles are built on a stronger and stiffer, fully boxed frame that is designed for improved crash-energy management. The front frame section, for example, has improved crush dynamics that provide the equivalent of 17.7 inches (450 mm) of additional crush space in vehicles that are only approximately 3 inches (76.2 mm) longer than their predecessors. The frame also is designed for improved vehicle-to-vehicle compatibility.
The all-new, fully boxed frame features hydroformed front and rear sections, as well as strategic placement of high-strength materials. The frame also features more reinforcing cross members than the previous-generation models, as well as stronger mounting brackets in key areas. The hydroformed front section frame rails have a wall-thickness of approximately 3.2 mm and are straighter with a more consistent cross-section than the previous-generation frame a design that delivers improved axial crush performance. Also, the new frame is 49 percent stiffer than the predecessor, which helps resist bending or twisting during a crash. (See Chassis Systems section for more information.)
The front rails of the frame are designed with enhanced vehicle-to-vehicle compatibility with smaller or lower vehicles during a crash. Compatibility brackets located on the forward position of the lower front frame rails are designed to buckle in a frontal or offset collision, reducing the motion of the frame into the smaller vehicle. The location of the brackets meets all car structure heights. GM crash-tested the tallest of the SUV models with some of the shortest cars on the road for crash compatibility.
Along with the frame, the upper body structure is designed to manage the energy of a crash, including improved side-impact and rollover performance. Strategic placement of high-strength steel throughout the frame and body structure provides additional support and helps maintain passenger compartment integrity during a crash.
The 07 SUVs body structure enhancements also include:
* A new A-pillar reinforcement made of high-strength steel that resists buckling
* High-strength steel roof-rail reinforcements on both sides of the B-pillar where they meet the roof rails contribute to improved roll-over performance
* A diagonal brace made of high-strength steel located beneath the driver and front passenger toe pan provides reinforcing strength for the vehicle and lower torso protection for passengers
* An all-new, single-piece rear D ring offers increased dimensional accuracy and reinforcing structure
* An enhanced front door hinge box adds strength to the forward section of the front door D-ring which helps reduce deformation during a crash
* Stronger knee bolster brackets (welded to the instrument panel cross beam) are designed to withstand higher loads during frontal impacts
* A new Z bracket adds strength to the area where the front-of-dash section of the body structure meets the floor pan, as does structural adhesive applied to the same area
The strength of the frame and body structure, extensive math modeling and internal crash tests contribute to GMs expectation that the new SUVs will be among the segments top performers in frontal barrier and frontal offset crash tests.
Other features that contribute to the SUVs strong performance during a crash include:
* Impact beams Front and rear impact beams are designed to absorb low-speed crashes and minimize vehicle damage. A more severe crash will cause the energy-absorbing bumper beam to crush. There also are two side-impact beams in each door.
* Passenger head protection Energy-absorbing foam padding and trim on the A-, B- and C-pillars, as well as the roof rail, are designed to spread the energy of a crash by crumpling and crushing on impact. The headliner also contains energy-absorbing material.
* Seat safeguards High-strength front seatbacks provide restraint during a rear-end crash. There also is a crushable pan between the seat frame and seat cushion the pan will crush to absorb energy in the case of a high load.
Occupant safety and security
Air bags: Dual-stage driver and outboard front passenger air bags are standard on all models. Children and smaller-stature front passengers are protected with GMs passenger occupant detection system. Roof-mounted head curtain side air bags are available on all models. These air bags inflate to restrain outboard passengers in all seating rows and are equipped with special tethers that hold the bags in place for several seconds for increased rollover protection and passenger containment.
The air bag systems sensors determine the severity of a crash, indicating whether the primary stage of inflation or the primary and secondary stages are required for maximum protection. The sensors are located at the front of the vehicle, on the radiator support beam.
In the event of a side-impact collision, the head curtain side air bags act like a protective curtain, unfolding from the roof rail between the A- and D-pillars in three-seating row vehicles and A- to C-pillars in two-row configurations. The first- and second-row positions are restrained by a larger side air bag and the third row has a dedicated air bag. Each side air bag has its own dedicated inflator for optimized fill rates into each curtain.
The roof-mounted head curtain side air bag system incorporates one of the segments first rollover indication sensors, which is located in the vehicles center tunnel. The sensor monitors the vehicles angle variance from level. If the angle indicates an impending rollover, the side air bags will deploy to provide an extra measure of occupant protection and containment. In this instance, the side air bags stay inflated longer than during a side-impact collision, because rollover incidents may last longer and the inflated air bags help keep occupants inside the vehicle.
Occupant protection from secondary impacts also is a feature of the roof-mounted head curtain side air bags. Based the severity of the event, the bags curtains are deployed whenever the second stage inflation of the frontal air bags is triggered. GMs safety engineers reasoned that a collision severe enough to trigger both stages of frontal air bag inflation is likely to cause a secondary collision. In this instance, the air bags deploy and remain inflated for several seconds following the initial collision, ready for a possible second impact.
Front safety belt pretensioners and rear safety belt features: Front safety belt pretensioners are standard on all models. In the event of a crash, they take up slack in the safety belt webbing to help secure the passenger in the seat and prevent him or her from submarining during the crash. It also helps to hold the passenger in position, so deceleration is at the same, slower rate of the vehicle and not a more abrupt stop.
The pretensioners are activated by a sensor, which triggers a pyrotechnic device that almost instantly reduces slack in the belt webbing. The safety belts are equipped with low-friction D-rings and low-effort retractors, so there is minimum pressure on the occupant, making the belts more comfortable to wear. Also, the pretensioners will activate in a rear-end crash an industry first in GMs full-size SUVs.
Second- and third-row seats have three-point safety belts in all positions. An added feature is an available comfort guide on the outboard seatbelts. This device has an elastic cord that helps to properly position the shoulder belt on smaller-stature occupants. The second- and third-row seats also come equipped with LATCH system child seat anchors, for both top tethers and lower latches, to simplify installation of child seats with these features. These anchors, which are secured to the body structure, are provided in the rear outboard seating positions.
Sophisticated sensors: The new SUVs are equipped with the segments most comprehensive system of crash impact sensors, which work together to provide 360 degrees of sensing tied to the central Sensing Diagnostic Module (SDM). This provides faster, more immediate data that is used to activate the vehicles numerous air bag safety features. The sensors include:
* Two forward sensors located on the frames most forward cross member measure deceleration crush, enabling SDM decisions in less than 10 milliseconds
* Four side-impact sensors one on each side-door beam provide more rearward sensing of side impacts than previous models
* A roll-over sensor that continually measures the vehicles pitch angle and signals the SDM if the angle indicates in imminent roll-over
* Rear sensors that detect rear-end impacts and trigger the safety belt pretensioners
Driver control
While designed to help protect passengers in the event of a crash, the new 2007 full-size SUVs also have features designed to avoid or lessen the chance of a crash. This starts with a wider front and rear track, which helps provide a more secure driving feel and a lower center of gravity. Also, the improved responsiveness while driving delivered by the new coil-over-shock front suspension, enhanced five-link rear suspension and new rack-and-pinion steering system provides the driver with a heightened feeling of control.
StabiliTrak electronic stability control: GMs sophisticated StabiliTrak electronic stability control system is standard on all 2007 full-size SUV models. Partnered with the new brake system and four-channel, four-sensor electronic brake controls, the system provides more precise, controlled ABS stops, as well as enhanced traction/yaw stability.
The Stabilitrak system has new rollover mitigation technology. Rollover mitigation adds software algorithms that use Stabilitrak sensors to proactively predict vehicle tip up on a flat road surface, and applies brake force to the outside front and rear wheels in order to reduce lateral force in the vehicle. This brake force intervention can help reduce the likelihood of a rollover in certain circumstances including fish hook maneuvers that involve sudden and rapid back-and-forth steering.
On 4WD models, StabiliTrak uses brake control to precisely manage the speed of each wheel as well as torque across the front and rear axles. On 2WD models, the system precisely controls the speed at each wheel and manages side-to-side torque on the rear differential. Individual brake sensors at each wheel provide signal the control module, enabling it to aggressively adjust brake pressure. However, traction is controlled by transferring torque across the rear axle rather than front and rear axles, as in 4WD models). When the vehicle is on a slippery surface, the traction system increases torque to the rear wheel that has the most traction.
On 2WD and 4WD models, the vehicle brake system provides torque-biasing to enhance traction and engine management as required to assist in controlling traction and yaw stability. The Autotrac transfer cases control algorithm has been integrated with the StabiliTrak and ABS systems to provide enhanced vehicle stability by managing the front-to-rear torque distribution.
StabiliTrak is always on and fully functional. It is automatically enabled, providing full stability, traction and ABS control, whenever the vehicle operates in forward gears. The system intervenes when it senses one or more of the wheels slipping or when the vehicle is not following the drivers intended path. It detects slippage during braking or acceleration and automatically adjusts individual wheel brake pressure, engine torque and, on 4WD Autotrac models, adjusts front to rear drive torque distribution, as required, to achieve optimal control.
Autotrac: Four-wheel drive models feature the Autotrac active transfer case, which helps keep the vehicle sure-footed in slippery driving conditions. When shifted to the Auto mode, Autotrac engages all-wheel drive traction automatically. The vehicle operates in rear-drive mode, but torque is automatically split between the front and rear wheels when the system senses all-wheel drive traction is needed. The process is smooth, quiet and almost undetectable.
New, segment-leading pre-emptive controls allow the Autotrac system increase the torque to the front axle on slippery roads prior before slippage occurs. This can increase control because the system anticipates rather than reacts to slippery conditions. Autotrac also is integrated with StabiliTrak, which now incorporates the signal from one of Autotracs slip-detection sensors to provide another measure of input to the stability control system. This new input allows StabiliTrak to operate more efficiently.
An available locking rear axle also helps provide sure-footed traction, particularly when towing. When rear wheel slip is detected, the rear axles lock to turn at the same rate, providing all available torque to both wheels. This is helpful for special circumstances, such as pulling a boat and trailer up a launch ramp.
New four-wheel disc brake system: A larger-capacity, four-wheel disc brake system with a new, four-channel ABS is designed to provide the new SUVs with superior stopping capability and the segments best braking feel. ABS is standard on all models, along with a full-function traction control system (traction control only on 2WD models). The headlining elements of the new brake system include larger-diameter front and rear disc rotors and new, stiffer brake calipers.
The front rotors measure 13 inches in diameter (330.2 mm), an increase of 1 inch (25.4 mm), or 15 percent larger. The front rotors also are thicker, with large cooling vents, providing enhanced performance and durability. The cast iron, dual-piston front brake calipers are 50 percent stiffer than before, which reduces the tendency for flexing during hard or prolonged braking. The stiffer calipers, along with dual pistons, contribute to a more direct and stronger brake pedal feel.
Rear brakes feature standard vented discs that measure 13.5 inches (342.9 mm), an increase of 0.5 inch (12.7 mm) approximately 7.5 percent larger. A revised single-piston rear brake caliper design contributes to reduced brake noise and more immediate braking response. Both the front and rear brakes use new, non-asbestos brake pad linings that can deliver up to 40,000 miles of performance during normal use.
The new brakes are complemented by a more robust, twin piston brake application system, including a larger master cylinder and active brake booster. Engineers tuned the application system to optimize the pedal feel and brake system responsiveness. It requires less pedal pressure to provide a more immediate brake response, delivering a dramatically improved feel.
A next-generation Bosch 8.0 ABS system is standard on all 2007 full-size SUVs. It has more precise valve control the requires less cycling of fluid from the brake master cylinder, resulting in reduced noise and enhanced braking feel when ABS is activated during braking. The new ABS system also is less complex and has reduced mass when compared with the previous system.
Full-function traction control uses the ABS system to regulate brake pressure to help provide enhanced traction for 2WD vehicles.
Ultrasonic Rear Parking Assist: The new optional Ultrasonic Rear Parking Assist system provides visual and audible warnings of objects behind the vehicle. The system operates when the vehicle is in Reverse, using fours sensors located at the rear of the vehicle. The new system is available in conjunction with a new, optional rear-view camera system, the first offered in a GM vehicle.
Rear-view camera system: The available rear-view camera system can be ordered with the optional navigation radio system. The camera provides a view of the rear of the vehicle not easily seen, even with the outside or inside rearview mirrors, allowing the driver to check for persons or obstacles directly in the path of the vehicle. It also assists with parallel parking or trailer backing. Drivers should still inspect around their vehicles for objects or playing children.
A large, clear picture of the cameras field of view is available on the navigation radio screen. The rear-view camera also works with the Ultrasonic Rear Parking Assist to provide an audible proximity reference to items in the cameras view. If an rear parking assist sensor detects a person or object, it alerts the camera.
The camera only functions when the vehicle is shifted into Reverse. For convenience, it will stay on for a calibrated length of time determined partly by vehicle speed after the vehicle is shifted into Drive. The camera is mounted in the license plate surround bracket for an integrated styling appearance. It provides approximately 20 feet (6.1 meters) of viewing distance behind the vehicle.
OnStar Generation 6: All models come standard with the OnStar Generation 6system, including a one-year subscription to the Safe & Sound plan. The OnStar service includes the General Motors Advanced Automatic Crash Notification (AACN) system, making crash data available to emergency services to potentially dispatch the appropriate life-saving personnel and equipment to crash scenes faster. If the vehicle is in a crash that activates an airbag, the OnStar system automatically notifies an OnStar Advisor who will check on the occupants or summon emergency help if necessary. OnStar also can assist authorities in locating a vehicle if it is reported stolen and provides remote door-unlocking service
Remote starting system: A factory-installed remote vehicle starting system is available on most models a first for GMs full-size SUVs providing customers with the convenience of starting the vehicle during inclement weather or other situations. The system has up to a 200-foot (61 meters) range and offers automatic climate pre-conditioning to warm or cool the vehicle prior to entry. On cold mornings, for example, the heat and defroster will be automatically turned on, even if the operator had last used the controls in a vent position.
The remote starting system is optional on some models and standard on others. Also, vehicles not originally equipped with the system are pre-wired at the factory so that the remote starting feature can be installed and activated by a GM dealership service department.
Tire pressure monitoring system: A revised and easier-to-use tire pressure monitoring system is standard on all models, providing drivers with peace of mind and contributing to a safer driving experience. The system alerts drivers via a signal on the instrument panel driver information center if a tires inflation status requires attention. In fact, the system sends a message to the information center each time the vehicle is started as part of a routine operations check. The driver also can use the information center to check the pressure of each tire. The pressure monitor sensors can detect air pressure differences to within one pound of the other tires.
Rain-sensing wipers: Available on some models is an optional rain-sensing windshield wiper system that automatically activates the wipers when precipitation is detected.
An infrared sensor located on the windshield (behind the inside rearview mirror) is used to detect raindrops. If rain or other precipitation is detected, the system signals the wipers to operate and adjusts wiper speed based on the intensity of the precipitation.
Stay tuned for updates, I will give them when I can.
Here is all the information on the GMT 900 line of trucks.
Source: www.gminsidenews.com
2007 GMT-900 Information
Comprehensively redesigned chassis and suspension systems of the 2007 GM full-size SUVs are the backbone of a refined feel and effortless driving experience. The athletic, responsive tuning of the vehicles establishes a new benchmark for full-size SUVs, while providing the driver with a heightened feeling of control.
The all-new chassis, with wider front and rear tracks, and new coil-over-shock front suspension support ride and handling characteristics that reinforce the SUVs live big, drive small mantra. These components provide a more agile feel and help deliver an exceptionally smooth ride, enhanced quietness and an overall feeling of strength and stability.
The strength of the new chassis supports the refined feel that is like no other full-size SUVs vehicles that live big, but drive small, said Terry Woychowski, vehicle chief engineer for full-size trucks. The combination of a stronger chassis and refined driver control features helps give the vehicles an effortless, controlled and smooth driving experience.
Features of the new chassis and suspension systems include:
* A new, fully boxed frame that is significantly stronger and stiffer with hydroformed front and rear bay sections
* Wider front and rear tracks approximately 3 inches (76.2 mm) in front and 1 inch (25.4 mm) in rear enable increased stability, as well as a smoother, more controlled ride
* New coil-over-shock front suspension delivers linear, responsive ride and handling characteristics
* Highly refined five-link rear suspension (with variable-rate springs) delivers damped, isolated road feel and supports a variety of load-carrying capabilities
* Use of monotube Autoride shock absorbers for more controlled, real-time damping capability
* New rack-and-pinion steering system delivers precise, responsive steering and contributes to the vehicles drive small feel
* All-new four-wheel disc brake system larger vented discs, stiffer calipers, more robust apply system and standard next-generation Bosch ABS system provides shorter stopping distances, better pedal feel and quicker brake response
* Larger-diameter standard and available wheels and tires, including segment-largest, 22-inch designs available on Cadillac Escalade
* Standard StabiliTrak electronic stability control with first-time GM application of rollover mitigation a software algorithm technology that uses system sensors to proactively predict vehicle tip-up and applies appropriate brake forces to prevent rollovers.
Fully boxed frame
For the first time, GMs full-size SUVs feature a fully boxed perimeter-type frame, the foundation on which the chassis, suspension, powertrain and body systems are mounted. Chevy Tahoe, GMC Yukon/Yukon Denali and Cadillac Escalade ride on a 116-inch (2,946 mm) wheelbase. Other models ride on a longer, 130-inch (3,302 mm) wheelbase.
The new, boxed frame design offers 49-percent increased torsional stiffness (side-to-side twisting) and 35-percent improved beaming frequency (front-to-back bending), compared with previous-generation vehicles. The stronger frame also supports an increased load capacity of approximately 5 percent.
The frames overall strength and increased stiffness are combined with more precise, integrated mounting brackets for powertrain, suspension and axle components, which enabled engineers to tune chassis and suspension bushings, springs and other elastomeric components for more accurate and refined ride and handling characteristics. The result is smoothness and responsiveness, with the capability expected of a full-size SUV. Quietness, a more linear driving feel and the feeling of isolation from the road also are enhanced.
A variable-height design of the boxed frame is matched with strategic application of high-strength materials throughout. The frame also has three distinct frame sections, or bays, each with specific strength and support characteristics. The front bay of the frameis an all-new design and features hydroformed frame rails made of high-strength steel.
The front bay includes the radiator support cross member, engine support cross member and front lower control arm cross member, all of which are welded to the hydroformed frame rails. GM pioneered the use of hydroformed frame rails for full-size SUVs on the previous-generation vehicles, introduced in 2000. The process uses highly pressurized fluid up to 20,000 psi to shape the frame rails. The revised design of the 2007 full-size SUV front bay section is approximately 40 percent stiffer than the previous-generation without a significant difference in mass.
A new powertrain mounting system is part of the front bay section. It is welded to the engine cross member and includes very stiff mounting brackets for the engine and transmission. The brackets house unique elastomeric bushings (on vehicles not equipped with Displacement On Demand) to dampen vibrations and foster a smoother ride and feel inside the passenger compartment. Vehicles with Displacement on Demand-equipped powertrains used hydraulic mounts to accommodate the changing rotational forces associated with the cylinder-deactivating technology.
The middle bay section of the frame extends from the A-pillar area to the C-pillar area. The boxed side rails of the middle bay support three stiffness-enhancing cross members. Strength also is built into joining of the front bay to the middle bay, with the front bays hydroformed rails slipping inside the boxed sections of the middle bay. This shingle-type design is welded and reinforced with a high-strength steel close-out plate that covers the overlapped joint.
The side rails of the middle bay section are constructed of two pieces of high-strength steel that are welded to form the sturdy box design. The outer section is made of 60-ksi steel that is 3.3 mm thick; the inner section is made of 30-ksi steel that is 2.2 mm thick. The rails also have a variable-height construction (between 110 mm and 210 mm) that enables strategic placement of strength-enhancing materials in certain areas for a more integrated, lower-mass design.
The rear bay frame section extends rearward from the C-pillar. Like the front bay section, its boxed rail sections are hydroformed and are joined to the middle bay with an overlapping, shingle-type construction. The rear bay section offers enhanced strength via a stronger, single-piece spare tire cross member, a more robust fuel tank carrier cross member and a thicker rear track bar cross member for the five-link rear suspension.
Wider front and rear tracks
The 2007 full-size 1500-Series SUVs have wider front and rear tracks than previous-generation models. The front track is more than 3 inches wider (77 mm) 68.2 inches (1731.8 mm) vs. 65 inches (1651 mm). The rear track is more than 1 inch wider (25 mm) 67 inches (1701.8 mm) vs. 65.98 inches (1675.8 mm).
A wider track promotes overall vehicle stability and a lower center of gravity, which the driver and passenger can feel through the vehicles secure ride and handling attributes, as well as flatter, more controlled cornering. The wider track widths also enhance smoothness.
Coil-over-shock front suspension
A new coil-over-shock front suspension is used on all light-duty models, along with a new front axle mounting system. The coil-over configuration offers smoother, more precise and nimbler ride and handling characteristics, especially with the larger wheel-and-tire combinations offered on the new SUVs. Vibration and harshness also is greatly reduced when compared to the previous-generation torsion bar front suspension design.
The new suspension system uses specially tuned coil springs and 46-mm monotube shock absorbers (except vehicles equipped with Autoride), along with steel upper control arms and forged aluminum lower control arms. The aluminum lower arms reduce un-sprung mass by approximately 20 pounds (9 kg) and the responsive monotube shocks bolster the vehicles more nimble driving feel.
Complementing the coil-over suspension design are new, stiffer frame attachments for the suspension components and a new, four-point front axle mounting system. These stiff, accurate mounting points including softer bushings located within brackets of the stiff front bay frame section contribute to the vehicles more controlled and linear driving feel.
Five-link rear suspension
A five-link rear suspension is used for 1500-Series 2WD and 4WD models (a heavy-duty leaf spring design is used on 2500 models). Although similar in design to previous models, the 2007 SUV rear suspension features a more robust rear axle design that offers increased payload weight. The axle system enhancements include a stiffer track bar bracket mounted to the rear bay frame section, a redesigned axle carrier and an axle rear cover that is 50 percent thicker for increased strength and durability.
Like the front suspension, the rear suspension uses new, stiffer frame mounts for suspension component attachment, along with variable-rate springs and monotube shock absorbers (except when equipped with Autoride). The accuracy and responsiveness of the tuned springs and monotube shocks provide superior dampening and ride control, regardless of whether the vehicle is carrying or towing a heavy payload.
Autoride real-time damping system
Vehicles equipped with the Z55/G59 suspension package include the segment-exclusive Autoride bi-state, real-time damping system. This advanced system enables an extremely refined ride with greatly reduced body motion. It also delivers instant suspension response to wheel speed, body position, vehicle speed, steering angle and braking.
Autoride is a semi-active, two-position damping control system that responds in real time to road conditions and driving conditions, based on body and wheel motions determined through sensors positioned at all four corners of the vehicle. The system uses up to four two-position monotube shock absorbers (each with an internal solenoid valve and air-lift/auto-leveling capability), four wheel-position sensors, a steering position sensor, engine torque monitor, brake apply sensor, vehicle speed sensor and an independent controller. Independent damping control at each corner of the vehicle allows specific damping to control body motions during higher-speed turns and driving over uneven surfaces.
Autorides air-lift/auto-leveling system includes air bags located over the shocks. An integrated air pump automatically adds air, when needed, to increase pressure in the air bags, raising the suspension to level the vehicles ride height when carrying passengers or a heavy payload. Conversely, air is bled from the bags when the payload is removed, returning the vehicle to a level ride height.
Suspension choices
The 2007 full-size SUVs are available with three distinctly tuned suspension systems, each tuned to provide an optimized ride with smoothness, a greater feeling of isolation from the road and minimal body movement:
* ZW7 Premium Smooth Ride: standard on 2WD and 4WD Chevy Tahoe and Suburban, GMC Yukon , Yukon XL, Yukon Denali and Yukon XL Denali
* Z55 (includes Autoride): standard on Cadillac Escalade, Escalade ESV and Escalade EXT; available on Chevy Tahoe and Suburban, GMC Yukon , Yukon XL, Yukon Denali and Yukon XL Denali
* Z71 Off Road: available on 4WD Chevy Tahoe and Suburban, GMC Yukon and Yukon XL
Both the ZW7 and Z71 suspensions use 46-mm front and rear monotube shock absorbers and tuned springs. The shocks feature large rod diameters that help reduce shock lag and fade over time. The ZW7 suspension uses variable-rate rear springs an uncommon feature in the segment to maintain body height and attitude under various payload conditions.
The unique Z55 suspension with Autoride uses automatically controlled air bags to regulate body height when the vehicle is loaded or unloaded. It also uses springs made of micro-alloy steel, which is stronger than typical spring steel yet offers mass savings.
All three suspensions have distinct bushing, spring and material characteristics. The firmness of the bushings, the spring rates and related materials were carefully selected after countless hours of comparison testing at GMs proving grounds and real-world testing on roads of varying conditions throughout North America . Suspension tuning also is specific to the size of the wheels and tires, as the 2007 SUVs offer a range of wheel sizes from 17 to 22 inches.
Rack-and-pinion steering system
For the first time on GMs full-size SUVs, a hydraulic power-assisted rack-and-pinion steering system is employed. The result is an optimized on-center steering feel and more immediate, precise steering response.
The new system mounts on the engine cross member of the front bay frame section, directly beneath the engine. This mounting position uses the inherent stiffness of the frame to enhance the direct and linear feel of the steering system, reducing the drivers need for continuous corrections during turns and sweeping corners. On 4WD vehicles, the steering rack is located forward of the front differential.
Steering ratios vary, depending on the vehicles suspension choice and wheel size. Combined with more immediate responsiveness, this gives the new 2007 full-size SUVs an easier, more maneuverable feel, particularly when parking in tight quarters. Low-friction, highly precise ball-and-needle bearings within the steering system contribute to the precise and immediate feel from the steering wheel. The system also is engineered with low-noise valve technology that helps reduce noise and vibration.
Four-wheel disc braking system
A new brake system design with larger four-wheel discs and an all-new ABS system helps GMs new full-size 1500-Series SUVs deliver superior braking performance with assuring pedal feel. The system includes larger-diameter rotors, stiffer front calipers and longer-life brake pad linings.
The front rotors measure 13 inches in diameter (330.2 mm), an increase of 1 inch (25.4 mm) approximately 15 percent larger. The front rotors also are thicker with large cooling vents, providing enhanced performance and durability. The cast iron, dual-piston front brake calipers are 50 percent stiffer than before, which reduces the tendency for flexing during hard or prolonged braking. The stiffer calipers, along with dual pistons, contribute to a more direct, linear and stronger brake pedal feel.
At the rear, the standard vented discs measure 13.5 inches (342.9 mm), an increase of 0.5 inch (12.7 mm) approximately 7.5 percent larger. A revised single-piston rear brake caliper design contributes to reduced brake noise and more immediate braking response. Both the front and rear brakes use new, non-asbestos brake pad linings that can deliver up to 40,000 miles of performance during normal use.
The new brakes are complemented by a new, twin-piston design brake application system, including a larger master cylinder and active brake booster. The more robust design enabled engineers to tune the application system to optimize pedal feel and brake system responsiveness. The system requires less pedal pressure to provide a more immediate brake response, delivering a dramatically improved feel.
A next-generation Bosch 8.0 ABS system is standard on all 2007 full-size SUVs. It has more precise valve control that requires less cycling of fluid from the brake master cylinder, resulting in reduced noise and enhanced braking feel when ABS is activated during a braking event. The new ABS system also is less complex and has reduced mass when compared with the previous system.
StabiliTrak electronic stability control
GMs sophisticated StabiliTrak electronic stability control system is standard on all 2007 full-size SUV models. Partnered with the new brake system and four-channel, four-sensor electronic brake controls, the system provides more precise, controlled ABS stops, as well as enhanced traction/yaw stability. The new, larger brake system allows for smoother, quieter StabiliTrak interventions and includes an active vacuum booster to increase system response time to changes in vehicle behavior.
On 4WD models, StabiliTrak uses brake control to precisely control the speed of each wheel and manage torque across the front and rear axles. On 2WD models, the system precisely controls the speed at each wheel and manages side-to-side torque on the rear differential. Individual brake sensors at each wheel provide instant signals to the control module, enabling it to aggressively adjust brake pressure. However, traction is controlled by transferring torque across the rear axle rather than front and rear axles, as in 4WD models. When the vehicle is on a slippery surface, the traction system increases torque to the rear wheel that has the most traction.
On 2WD and 4WD models, the vehicle brake system provides the torque-biasing to enhance traction and engine management is used, as required, to assist in controlling traction and yaw stability. The Autotrac transfer cases control algorithm has been integrated with the StabiliTrak and ABS systems to provide enhanced vehicle stability by managing the front-to-rear torque distribution.
StabiliTrak is always on and fully functional. It is automatically enabled, providing full stability, traction and ABS control, whenever the vehicle operates in forward gears. The system intervenes when it senses one or more of the wheels slipping or when the vehicle is not following the drivers intended path. It detects slippage during braking or acceleration and automatically adjusts individual wheel brake pressure, engine torque and, on 4WD Autotrac models, adjusts front to rear drive torque distribution, as required, to achieve optimal control.
Rollover mitigation
The Stabilitrak system has new rollover mitigation technology. This technology adds software algorithms that use Stabilitrak sensors to proactively predict vehicle tip up on a flat road surface, and applies brake force to the outside front and rear wheels in order to reduce lateral force in the vehicle. This brake force intervention can help reduce the likelihood of a rollover in certain circumstances.
Wheels and tires
Complementing the strong, athletic styling of the 2007 full-size SUVs is a range of large standard and available wheel and tire sizes, including segment-largest 22-inch wheels and tires available on the Cadillac Escalade. New P-metric tires for 18-, 20, and 22-inch sizes have a nylon cap ply that enhances strength and durability.
Chevy Tahoe and Suburban, along with GMC Yukon and Yukon XL, come standard with 17-inch wheels and touring tires that provide excellent comfort and low road noise. Uplevel models offer styled aluminum wheels different designs for Chevy and GMC models including machine-face and polished-face wheels. Tahoe, Suburban, Yukon and Yukon XL also offer optional 20-inch wheel-and-tire combinations, including six-spoke, bright-face aluminum wheels. Eighteen-inch wheels are standard on GMC Yukon Denali and Yukon XL Denali, with 20-inch wheels optional.
Cadillac Escalade models come standard with 18-inch aluminum wheels, with a 22-inch wheel-and-tire combination optional. Both the 18-inch and 22-inch wheel designs have a new seven-spoke design that is specific for Cadillac models. Standard 18-inch wheels have a machine-face design, with chrome appearance available.
GMs all-new 2007 full-size SUVs are characterized by taut, athletic exterior styling with distinct design cues. The sleeker exterior designs convey strength and are aerodynamically tuned to bolster fuel economy, as well as enhance quietness.
Along with their athletic and capable presence augmented by a wider track that creates a more confident, broad-shouldered stance the new SUVs have a tailored appearance, with new, wraparound fascias and improved tolerances. The overall effect is a leaner, more refined appearance that suggests a trimmer vehicle, belying the vehicles nearly 3-inch (76.2 mm) increase in overall length.
The new SUVs represent clean-sheet approaches to design, said John Cafaro, chief designer for full-size SUVs. Each model carries the personality of its respective brand, but all share a tight, masculine design ethic that speaks to the expectations of an authentic full-size SUV one look and theres no doubt about the capabilities of these vehicles.
All major body components and sheetmetal on the 07 SUVs are new. The front-end sheetmetal differs between all models. Wraparound front and rear fascias also are new and are primary contributors to the vehicles leaner, more refined appearances. The wraparound fascias flow into the front fenders with an almost imperceptible tolerance, creating a virtually seamless appearance. Cadillac Escalade models also feature unique doors, side trim and new front fender vents that provide the vehicles unmistakable distinction.
Escalades bold styling helped enmesh the vehicle in popular culture and the new models take that boldness to a heightened level, while maintaining the iconic cues that pushed Cadillac design to the forefront of contemporary styling, said Cafaro.
A more steeply raked, 57-degree windshield gives the new SUVs the segments best overall aerodynamics of approximately 0.363 cd. The more aerodynamic profile helps reduce wind noise, as do narrowed gaps between panels and tighter, flusher mounting of the exterior components, such as the grille, headlamps and trim.
Larger standard and available wheels, including optional 20-inch wheels on Chevy and GMC models, as well as 22-inch wheels on Escalade, are tailored to fit the vehicles wheel openings. This precise wheel-to-body relationship gives the vehicle a more refined look and, with the chassis wider track, a more athletic presence.
Numerous standard and available features complement the new SUVs design, including new-design flat-blade windshield wipers and styled wiper arms, standard front tow hooks (4WD models), an available power-assisted rear liftgate, available factory-installed articulating running boards and a larger available sunroof.
Detailed cues, such as jewel-look lighting elements and doors that extend over the rockers for a smoother, more integrated side view are characteristic of the vehicles precise, refined design ethic. Highlights include:
* Wraparound front fascias
* Tighter panel and trim tolerances
* Jewel-look headlamps and taillamps
* Power-assisted rear liftgate (optional)
* Streamlined outside mirrors and roof racks
* Larger grab-style door handles
* Standard running boards with an integrated design
* Optional articulating running boards (late availability)
* Enhanced lighting performance, with standard HID headlamps on Cadillac models
* New flat-blade windshield wipers
* Ultrasonic Rear Parking Assist
* Rear-view camera
* Heated windshield washer fluid
* Larger sunroof with express open/close feature (optional)
* In-glass AM/FM radio antenna
* Streamlined roof rack styling
Chevy Tahoe design
Tahoe wears Chevys new dual-port front-end design theme, which was introduced on vehicles such as the 2006 Impala. On Tahoe, the theme is embellished with prominent borders to reflect the vehicles rugged, sporty and go-anywhere personality.
A body-color grille surround with argent-color mesh grille inserts is accented with chrome, with a prominent, gold-color Chevy bowtie in the center of the grille area. The upper and lower grille sections, along with round halogen fog lamps, are part of the integral assembly of Tahoes new, wraparound front fascia. The lower section of the fascia incorporates the front license plate holder and two recessed, integrated tow hooks. The bottom of the fasica incorporates a skid plate design cue that accents Tahoes off-road-ready appearance.
Tahoe has large, integrated headlamps that flow into the corners of the fenders. Four separate lamps are housed in round, reflective-optic pockets that are set against a darker background. This provides a floating effect that, with the attitude of the upper headlamp housings, gives the Tahoe a deep, serious face. Beneath the headlamp housings are the daytime running lamps/parking lamps. Fog lamps are standard and integrated in the lower fascia.
As with the front of the vehicle, a new fascia wraps around the rear of the vehicle for a seamless look that eliminates a large bumper-to-body gap. A gold bowtie emblem is located above the license plate pocket on a large pocket/from that also houses the components for the optional rear-view camera system (when equipped). The license plate pocket is integrated in the center of the liftgate. The liftgate can be manually operated or electrically operated when equipped with the optional power-assisted liftgate feature.
Tahoe features distinctive rear styling, highlighted by three lighting elements stacked on top of each other and mounted in a ruby-red, jewel-look housing. The lighting elements have bright trim rings. Tahoes styling also is complemented by a new family of wheels and tires, including standard 17-inch wheels and available 20-inch wheels. The new family of wheels includes available bright machine-face, polished or chrome finishes.
GMC Yukon and Yukon Denali design
Yukon and Yukon Denali models have a new, distinct appearance that introduces a new design language for GMC. The design is characterized by large, round headlamps set in vertical housings that taper at the top and wrap around into the front fenders. The round lamps a larger round lamp on the bottom with a slightly smaller lamp on top have cylindrical mounting pockets that create a detailed three-dimensional appearance when viewed through the crystal-clear lenses.
The headlamps are separated by a large grille opening that contains a prominent, red GMC logo. The two-piece grille, with chrome surround trim, includes a taller upper section, with h orizontal, dark-colored bars on Yukon and Yukon XL models. The upper section channels air to the radiator and the lower section frames the front license plate holder and the standard integrated tow hooks.
Yukon Denali and Yukon XL Denali feature an updated version of the bright grille design that makes the vehicles instantly recognizable. For the 07 models, the grille design has a more intricate mesh pattern that retains the Denali-specific chrome finish. The unique grille is accented by additional premium exterior trim cues.
The grilles of Yukon and Yukon Denali models, along with standard halogen fog lamps, are part of the integral assembly of the full wraparound front fascia systems shared among all the new SUVs. The fog lamps, like the large round headlamps, feature jewel-like optics. A molded-in, spear-shaped feature line runs across the fascia, above the fog lamps. This shape is carried by the protective bodyside moldings around the vehicle.
As with the front end, the rear of the Yukon features an integrated, wraparound fascia and unique lighting. The taillamp design includes three chrome-ringed, stacked ovals and red-color clear lenses. The three lighting elements create a concentric ring design that mimics the appearance of the round headlamps.
Distinct from the Chevy and Cadillac models, Yukon has black D-pillars with a black graphic trim piece extending from the D-pillar quarter glass to the backlight glass.
Cadillac Escalade design
The iconic design cues that made the Escalade a cultural phenomenon are enhanced with the 2007 model cues that established a new design language for all Cadillac vehicles. The 07 model also incorporates elements introduced on the landmark Sixteen concept vehicle. These elements include vertical headlamp housing with HID tri-segment lighting elements and new, stylish front fender vents.
Escalade features a more prominent Cadillac wreath-and-crest emblem in the center of the traditional shield-shaped grille. It is confidently scaled to the proportions of the bold front end styling. The grille surface is predominantly chrome, with painted elements that add texture and visual depth. It is inset with compartmentalized groups of jewel-like vents and a detailed chrome-trim liner that has a textured screen with bright edges and black sides. The overall look is more detailed, enhancing Escalades luxury aura.
Escalades new, larger HID headlamps further the vertical-design theme established by the previous-generation model, but are more prominent and feature three distinct elements. The lamps interior parabolas are highly reflective and contribute to the jeweled looked when viewed through the crystal-clear lenses. The Cadillac logo is etched into the bulb shields, which contain new HID lighting elements.
The Escalade has a unique, wraparound front fascia that creates a seamless appearance. The lower portion of the fascia incorporates recessed, integrated tow hooks, owing to the Escalades primary mission as a capable full-size SUV. In true Escalade fashion, the tow hook openings make a stylish design statement.
The new front fascia flows smoothly into the front fenders, which are distinguished with Escalade-exclusive front fender vents. The vents, located at the top-rear corner of the fenders deliver a detailed appearance, with three sections set off by a chrome top bar and chrome surround trim. The vents add visual distinction to the Escalade lineup and are sure to become signature hallmarks, like the vertical headlamps and prominent wreath-and-crest grille emblem.
As with the front end, Escalade models have a specific wraparound rear fascia. The license plate holder is integrated into the liftgate and a prominent wreath-and-crest emblem is mounted above it. The fascia also incorporates sensors for the standard Ultrasonic Rear Parking Assist feature, as well as the standard trailer hitch platform. The platform is covered to maintain Escalades tailored appearance, but is easily removable.
Escalades vertical lighting theme also is carried to the rear of the vehicle, with two arrays of elegant LED-lit taillamps. The lamps feature indirect optics and numerous sources of illumination per unit, which provides a broader, more even lighting display and eliminates the pinpoints of light normally associated with LEDs.
As part of its bold, powerful appearance, Escalade offers optional 22-inch wheels and tires the largest factory-installed wheels in the full-size segment. All Escalade models including those equipped with the standard 18-inch wheels and tires feature a unique seven-spoke wheel design.
Aerodynamics and wind noise reduction
GMs new full-size SUVs are the most aerodynamic in the segment with a 0.363 coefficient of drag. The more aerodynamic shape enhances fuel efficiency and quietness.
Contributors to the SUVs aerodynamic efficiency include:
* Front air dam Carefully integrated stylish wraps into the leading edge of the tires. Compared to previous models, it is lower and wider.
* Tighter tolerances New fascia designs, headlamp and grille mounting, and trim mounting attention to detail improve or eliminate gaps and improve tolerances compared to previous models, reducing drag.
* Improved sealing Airflow into the grille is more efficient with improved front-end sealing, which almost eliminates air leak paths that can create drag.
* Streamlined components Exterior components such as the rear-view mirrors, running boards and roof rack are aerodynamically tuned for reduced drag and noise. The high-mounted stop lamp (also known as the CHMSL) also is aerodynamically tuned, located in a housing that extends nearly the entire width of the roof, with the Cadillac Escalades sharp-edged CHMSL offering the most aerodynamic aid of all the new SUVs lamps.
Improved aerodynamics help enhance driving quietness, as do numerous body sealing features designed to reduce wind noise including new-design door-to-body seals. The primary door seal has a sculpted shape with multiple internal chambers in the material that condense to provide a tighter fit when the door is closed. An auxiliary door seal, which runs from the lower A-pillar to the top of the doorframe and around the second-row door opening, has a combination of soft and stiff rubber material to prevent movement during driving. This helps maintain a constant seal, virtually eliminating the sound of wind noise as the vehicle speed increases.
Tighter tolerances
All models feature a one-piece, body-color front fascia that wraps around into the front wheel openings, creating a sleeker, more integrated appearance. The fascia covers the front bumper beam, eliminating the conventional look of a bumper separated from other body components. This more seamless design is one of the many details that helps improve aerodynamics and reduce wind noise. Hood-to-fender gaps are reduced, as are the headlamp-to-fender gaps.
At the rear of the vehicles, gaps are reduced around the liftgate and fascia top that creates a refined and precise appearance The liftgate-to-quarter panel and liftgate-to-taillamp tolerances have also been reduced with a new, one-piece door ring, or D-ring. The D-ring provides an extremely strong, dimensionally accurate foundation for details like the taillamp mounting holes. The quarter panels, underbody and roof all are welded to the D-ring in the upper body structure, which enables the precise fit and enhances the tight structure of the vehicles.
From the side, all models have a more integrated appearance, with t he increased windshield angle helping create a smoother transition to the roofline. The streamlined look is accented with smoother, lower-profile roof racks.
Doors extend down and wrap over the rockers for a cleaner, one-piece appearance and improved bodyside integration. The Cadillac Escalade features different door designs and window moldings that fit the contours of the unique front-end styling. Badging on all models consists of simple, element chrome letters on the front doors and liftgate. All models feature discreet GM Mark of Excellence insignias located on the forward edge of the front doors.
Rear-view mirrors are styled for improved aerodynamics and reduced wind noise. All model feature new, refined grab-style door handles that are designed to stand off from the edge of the vehicle for easier actuation. Door closing is effortless and quiet.
Standard running boards are integrated with the exterior design themes and optional power articulating running boards (available later in the model year) automatically extend when the doors are opened. When not in use, the boards retract inward, giving the vehicle a sleeker, more refined appearance.
Power liftgate
A new power liftgate is available on most models. The liftgate can be remotely opened, regardless of whether the vehicle is locked, by pressing and holding a key fob button for one second. Pressing and holding the key fob button closes the liftgate. If the vehicle is locked, the gate also locks. A second activation switch is located in the overhead console. A third control button on the liftgate itself will also automatically close the gate, after the vehicle is loaded.
Vehicles not equipped with the power liftgate feature an electric liftgate release feature. The liftgate has a pull handle with a micro-switch release. It allows the electrically operated liftgate latches to be released in an easy, one-touch manner by simply pressing the pull handles release pad.
The glass in the liftgate also has an easy access release switch. A pull strap and pull cup on the inside trim allow operators to close the liftgate, without having to grab the outside of the gate.
Larger power sunroof
A power-operated sunroof is available on the 2007 full-size SUVs and is larger than previous models. It is approximately 2 inches (50.8 mm) wider, allowing for a greater open-air driving feel. The sunroof also has a new express open/close feature and pop-up wind deflector that helps reduce wind noise with the sunroof is open.
Windshield wipers and heated washer fluid
New, flat-blade windshield wipers, which are pre-formed to contour the curvature of the windshield glass, provide more uniform pressure on the windshield glass to enhance clearing, minimize streaking and nearly eliminate wind noise. The blades are mounted on stylish arms that have less structure than previous-design models, eliminating joint and other points that can freeze, bind or cause chatter.
Rain-sensing wiper activation is available on some models (standard on Escalade), which automatically turns on the wipers when precipitation is detected. The system also automatically varies the wiper speed depending on the amount of precipitation. An infrared sensor mounted near the top of the windshield (behind the inside rear-view mirror), determines when precipitation on the windshield is sufficient to warrant turning on the wipers.
A heated windshield washer fluid feature also is available on some models (standard on Escalade). The heated fluid provides improved and faster clearing of frost and light ice buildup, as well as enhanced insect cleaning capability.
Regular washer fluid operation is available with the standard stalk-mounted control, while the heated fluid is available via an instrument panel control. When activated, regular washer fluid is diverted to a reservoir, where it is briefly super-heated to up to 140 degrees F. The system provides enough heated fluid for four cycles of use.
Ultrasonic Rear Parking Assist
The new optional Ultrasonic Rear Parking Assist system provides visual and audible warnings of objects behind the vehicle. The system operates when the vehicle is in Reverse, using four sensors located at the rear of the vehicle. The new system is available with a new, optional rear-view camera system, the first offered in a GM vehicle.
Rear-view camera system
The rear-view camera system is available with the optional navigation radio system. The camera provides a view of the rear of the vehicle not easily seen, even with the outside or inside rearview mirrors, allowing the driver to check for persons or obstacles directly in the path of the vehicle. It also assists with parallel parking or trailer backing. Drivers should still inspect around their vehicle for objects or playing children.
A large, clear picture of the cameras field of view is available on the navigation radio screen. The rear-view camera also works with the Ultrasonic Rear Parking Assist to provide an audible proximity reference to items in the cameras view. If an RPA sensor detects a person or object, it alerts the camera.
The camera only functions when the vehicle is shifted into Reverse. For convenience, it will stay on for a calibrated length of time determined partly by vehicle speed after the vehicle is shifted into Drive. The camera is mounted in the license plate surround bracket for an integrated styling appearance. It provides approximately 20 feet (6.1 meters) of viewing distance behind the vehicle.
GMs 2007 full-size SUVs have inviting new interiors that are quieter, more spacious and comfortable, with heightened refinement throughout their environments.
Like the exterior styling that envelops them, the all-new interiors have greater brand distinction than any previous generation, with each model highlighting characteristics that embody its brand. Unique cluster facings, graphics, wood and metal accents, steering wheels and color schemes are the distinguishing brand identifiers inside. All models benefit from the use of premium materials, chrome accents, and soft touch surfaces with low gloss levels, as a high level of refinement and quality craftsmanship is standard equipment across all brands.
Cadillac Escalade models have an exclusive luxury interior, befitting the king of luxury SUVs. Escalades specific design includes a unique instrument panel, door panels, seats, instrumentation and center console. Escalade also receives enhanced premium materials and features, such as foam-backed cast skin covering for the instrument panel, upper door trim and armrests, unique instrument lighting, fabric-covered interior pillars, available heated and cooled front seats, available heated steering wheel and a DVD entertainment system with flip-down screens for the second- and third-row occupants.
All 07 full-size SUVs are roomier and more comfortable, with greater passenger space and cargo carrying capacity. Instrument panels that are positioned lower and further forward add to the feeling of spaciousness, as well as improve outward visibility. There are new comfort features such as best-in-class cabin quietness and new, highly styled and supportive seats. Unique features, such as the innovative easy use power fold-and-tumble rear seat eases access to the third-row seat.
These are the most refined and luxurious SUV interiors, period, said Gary White, General Motors North America vice president and vehicle line executive for full-size trucks. The passenger environments represent GMs drive to produce the quietest, most finely crafted interiors in the segment.
Refinement and craftsmanship
The perceptual quality of the new full-size SUV interiors far surpasses any previous generation. It results from the close attention to details engineered into every facet of the cabin and is highlighted by flush surfaces, tight gaps and tolerances on the instrument panel, center stack, clusters and other components.
Most gaps on the instrument panel and cluster have been narrowed to 0.5 mm or less. Some gaps have been totally eliminated. Flush-mounted accessories and controls, such as the climate control/radio center stack create a seamless, more finished appearance appearing as a single unit rather than components stacked together.
Similar attention was given to concealing fasteners and metal structural components of all folding seats. New seat close-outs provide a more finished, crafted appearance to the seats when they are in a folded or tumbled forward position. The seat tracks also are concealed with covers.
The two-tone interior color scheme, executed with rich, warm colors, dramatically enhances the appearance and aura of the new SUVs interiors. The upscale styling is complemented by new, soft-touch and low-gloss finishes for the instrument panel and other trim pieces. Also, the color and grain of materials were carefully selected to provide a premium look. Upscale details also include LED backlighting for instrumentation and chrome accents on gauges and vents. The comprehensive result of these elements is a rich, harmonious appearance throughout the interior.
More expansive feel
An enhanced feeling of spaciousness is immediately apparent when seated in the all-new 07 SUVs. This is due to the repositioned instrument panel that, compared to the previous-generation SUVs, is moved forward and down 5.75 inches (146 mm). Also, a faster windshield rake of 57 degrees (vs. the previous models 50 degrees) helps create an airy, panoramic view.
GMs new SUVs also deliver more passenger space and room to stretch, as well as seating rows designed for easier entry and egress. The front seats offer 1 inch (25.4 mm) of increased rearward travel and the second-row seats offer 0.4-inch (10 mm) increased legroom: 39 inches (990.8 mm). Also, the second-row seatback angle is increased from 23 degrees to 25 degrees, which enhances seat comfort.
Engineers also were able to provide slightly more shoulder room for first- and second-row passengers while packaging the roof-mounted head curtain side air bags. To provide more generous third-row shoulder room, the seats hip point was moved slightly forward and upward. Third-row headroom also is increased to 37.9 inches (963.5 mm) 0.6-inch (15.2 mm) more than before. The seating position of the third-row seats enhances outward visibility, too.
Cargo room of the Chevy Tahoe, GMC Yukon/Yukon Denali and Cadillac Escalade has increased by 4.2 cubic feet (118.9 liters) behind the second row seats and 2.3 cubic feet (65.1 liters) behind the third row.
Enhanced comfort
Seating comfort for the SUVs, which was already the best in the segment, is enhanced with new, European-style seats that are slimmer and more comfortable than previous models. The seats have a tailored appearance, with double-stitched French seams, and are more supportive, with firmer foams and more supportive side bolsters. The streamlined look also comes from anchoring the outboard safety belts of first- and second-row seats to the vehicles pillars.
Heated first- and second-row seats on both bench and bucket seats are available. Cadillac Escalade also offers heated and cooled front seats that feature perforated leather designed to enhance airflow. Additional comfort-enhancing features include second-row armrests that are curved to match the contour of the seatback and longer armrests for all bucket seats. Also, the third-row seats offer integrated storage bins and cup holders.
Another first is third-row seating available in two- or three-passenger configurations. In fact, all three seating rows of the Chevy Tahoe and GMC Yukon/Yukon Denali are offered in two- or three-passenger configurations; Cadillac Escalade comes with two front bucket seats. A variety of cloth and leather-covered seating surfaces are available on Tahoe and Yukon ; leather is standard on Yukon Denali and Escalade. All cloth seats us heavy-duty fabric with double-stitched French seams; durable, high-wear Meridian leather is used on Tahoe and Yukon . Nuance leather is used on Escalade and Denali seating surfaces.
Interior details and convenience features
All models offer distinct interior styling, appointments and features, including the Escalade models unique instrument panel/seating/center console configurations. Highlights for all models include:
* New, streamlined European-styled seats with tailored appearance designed for increased support and comfort
* Increased front seat travel
* First- and second-row outboard safety belts mounted to door pillars
* Second-row seats moved rearward for increased legroom and seatback angle increased for more comfort
* Available first- and second-row seat heating
* Third-row seating with increased headroom and improved outward visibility
* Available two- or three-passenger third-row seating
* Increased shoulder room on first- and second-row seats, with roof-mounted head curtain side air bags
* Finished seat close-outs that conceal seat hardware
* Innovative fold-and-tumble second-row seat
* Standard tri-zone manual climate control (Tahoe and Yukon ); tri-zone automatic climate control standard on Yukon Denali and Escalade, and available on Tahoe and Yukon
* Revised HVAC system with single-button front-seat control for rear passengers
* Increased cargo room behind second- and third-row seats, along with new storage bins and cup holders attached to third-row seats
* New center console design with segments largest storage capacity of more than 20 liters (0.7 cu. ft.)
* 25-percent larger glove box with spring-damped opening feature
* Available power-assisted rear liftgate
* Available heated windshield washer fluid
* Larger available sunroof with express open/close feature
* Available power-adjustable pedals
Cadillac Escalade adds additional luxury and convenience features, including:
* Unique instrument panel and center console design
* Premium soft instrument panel and interior trim materials, including Meridian leather covering
* White-LED continuously backlit gauges
* Available heated and cooled front seats with perforated leather-covered seating surfaces
* Unique steering wheel design with premium wood trim options
* Available heated steering wheel
* Rear-seat entertainment system with second-row and third-row DVD screens available
Power fold-and-tumble second-row seat
New for the 07 SUVs are second- and third-row seats that fold and tumble for easier third-row entry and egress. The second-row features an industry-exclusive power fold-and-tumble feature, which remotely unlatches the seat to send it into its forward-folded and tumbled position. This greatly eases access to the third seating row, while also easing the burden of parent holding a child there is no need to fumble with both hands to release and fold the seat forward.
The power fold-and-tumble feature operates with the press of a button from the first-row overhead console or door pillar. The button activates a release mechanism on the seat latch, allowing the seat to fold forward into the tumbled position. (The seat must be returned to the original seating position by hand.)
Also adding convenience to seating and storage options are the SUVs easily configurable and removable third-row seats. The seatbacks fold flat to create a convenient load platform. They also can be removed quickly to create additional storage space. Two easy-to-operate levers on the seatback allow the seats to be quickly removed.
Cargo room and new power liftgate
The 07 models of the Tahoe, Yukon/Yukon Denali and Escalade offer increased cargo room of 4.2 cubic feet (118.9 liters) more behind the second row seats and 2.3 cubic feet (65.1 liters) more behind the third row. This gives the vehicles a cargo capacity of 108.9 cubic feet (3,084 liters) when the second-row seat is folded and tumbled forward and the third-row seat is removed. There also is 60.3 cubic feet (1,707.7 liters) of cargo space with the second row seat in place and the third-row seats removed. There is 16.9 cubic feet (478.6 liters) of cargo space behind the third-row seats.
The significant increase in cargo capacity is achieved in vehicles that have grown in length by only approximately 3 inches (76.2 mm). Engineers found the additional room by streamlining the cargo area with relocated and flush-mounted air conditioning ducts and slimmer liftgate trim.
Along with cargo volume, the new SUVs have the capability to carry 4 x 8-foot sheets of plywood and even wider T111 tongue-and-groove paneling without removing the rear seats. This is accomplished by simply folding and tumbling the second-row seat forward and folding the third-row seat flat.
A new, power-assisted rear liftgate is available and is a first for any GM SUV. The gate can be operated with the key fob remote or with controls located inside the vehicle. The liftgate opens with a single push of the button, easing the burden of fumbling for keys and manual operating the liftgate with arms full of groceries or children. Closing the liftgate simply requires another push of the button.
Storage options and convenience features
The all-new interior designs of the 07 SUVs include (on vehicles equipped with front bucket seats) large center consoles with the segments largest storage capacity 0.7 cubic foot (20.1 liters) of undivided volume. Instead of running up and over the center stack, the console flows beneath it, narrowing the gaps to the instrument panel and maximizing storage space.
A leather-like, soft-covered console lid on the Chevrolet and GMC models adds to the vehicles premium feel while functioning as an armrest for both front passengers. When opened, the lid reveals the storage compartments many features, including a power point suitable for charging cell phones while they are discreetly stored and flocking that can prevent items from moving or rattling. At the front of the console are two cup holders, which can be repositioned or removed altogether. The rear of the console houses two cup holders for second-row passengers, along with air conditioning vents and a power point that can be used for video input, handheld games and rear seat audio controls.
Cadillac Escalade features a dual-opening console lid, with a soft, leather-like cover. A wood trim appliqué adds distinction and matches the Northern engraving wood trim found elsewhere in the interior. The wood trim runs through the center of the console, providing a sense of compartmentalization.
The Escalades console opens with a chrome, spring-damped release button that fosters the vehicles refined nature. Multilevel storage within the console includes a smaller, contained space for delicate items like sunglasses. Releasing the second lid opens up the consoles large storage compartment. Additional premium features include separate front compartments, including one with a 12-volt power source. At the rear of the Escalades console are two, chrome-ringed cup holders for second-row passengers.
Chevrolet and GMC vehicles equipped with a front 40/20/40-split bench seat feature a large fold-down center section when a passenger isnt occupying the center seat position that provides two cup holders and a large, deep storage bin suitable for holding a lunch bag.
The new SUVs glove boxes have 25 percent more storage capacity as well as a single-bin configuration. The glove box capacity is 0.18 cubic foot (5 liters) and the lid is spring-damped, which provides a quiet, high-quality feel when opening or closing the glove box. Additional storage comes from front- and rear-door map pockets, as well as front seatback compartments that are large enough to store a road atlas.
Climate control system
Chevy Tahoe/Suburban and GMC Yukon/Yukon XL have standard manual-control tri-zone climate control. Automatic tri-zone climate control is available on Chevrolet and Yukon models, and standard on Yukon Denali and Cadillac Escalade models. Engineers enhanced the tri-zone systems to provide quieter operation, more efficient cooling and airflow for second- and third-row passengers, and improved side-window defogging.
The tri-zone systems also feature new controls that simplify operation, including one-button control for the automatic system that controls rear air conditioning. And, as with previous systems, the 07 SUVs climate systems continue to allow up to 30-degree F difference in temperature setting between the driver and front passenger, as well as separate controls for rear-seat passengers.
Heated windshield wiper fluid
Another first for GM SUVs is the optional heated windshield washer fluid system, which more effectively removes bug spatter and thin layers of ice and frost. The fluid is heated up to 140 degrees F (60 C).
The heated fluid is used when activated by a special button on the instrument panel; ambient temperature fluid is used when the driver selects the standard washer system on the control stalk. When the heated system is activated, washer fluid is directed to a special reservoir and super heated very quickly for approximately 20 seconds. Enough fluid enters the reservoir to accommodate four cycles of windshield cleaning.
Larger power sunroof
A larger, power-operated sunroof is available on the 2007 full-size SUVs. It is approximately 2 inches (50.8 mm) wider, allowing for a greater open-air driving feel. The sunroof also has a new express open/close feature and pop-up wind deflector that helps reduce wind noise with the sunroof is open.
Adjustable pedals, rear-view camera and Ultrasonic Rear Parking Assist
Features including Ultrasonic Rear Parking Assist, rear-view camera system and power-adjustable pedals are available on most models (some features not available on base models). Yukon Denali and Escalade models offer additional comfort and convenience features, including an optional heated steering wheel.
Ultrasonic Rear Parking Assist provides visual and audible warnings of objects behind the vehicle. Similarly, the optional rear-view camera system (requires optional navigation radio system) provides a visual reference for the rear of vehicle and works with the Ultrasonic Rear Parking Assist to provide assistance for maneuvers such as backing a trailer. (More information on the Ultrasonic Rear Parking Assist and rear-view camera systems is available in the Safety and Security section.)
The power-adjustable pedals help ensure a comfortable and safe driving position for almost every-sized driver. At the push of a button, the pedals move on an angle upward to meet the leg length of smaller-stature drivers.
A new generation of GMs legendary small-block V-8 engine is the power behind GMs all-new full-size SUVs, delivering increased performance and fuel economy through advanced technology such as Displacement On Demand and variable valve timing.
The Gen IV small-block Vortec V-8 engine family including the 5.3L V-8 is standard in all models, with displacements ranging from 4.8L to 6.2L, and estimated horsepower ranging from 290 horsepower (216 kw) to 400 horsepower (298 kw).* The engines are backed by proven Hydra-Matic electronically controlled automatic transmissions, including a new 6L80 six-speed.
The new Vortec engines represent the fourth generation of the small-block V-8, which debuted in 1955. Highlights include:
* Revised cylinder block design with externally mounted knock sensors
* High flow cylinder heads on 6.0L and 6.2L engines
* Variable valve timing on 6.0L and 6.2L engines
* Displacement On Demand on 5.3L and aluminum-block 6.0L engines
* Electronic throttle control
* 58X ignition system
* New, more powerful E38 32-bit controller
* Enhanced quietness and smoothness
* Returnless fuel system
* E85 fuel capability on some 5.3L engines
* Stringent validation and durability testing throughout development process
The Vortec Gen IV V-8 family delivers balanced performance and efficiency through technical innovation, said Christopher Meagher, assistant chief engineer. Fuel-saving features, such as Displacement On Demand, affirms the small-block V-8s leadership role in trucks.
Supporting the high-performance capability of the 6.2L engine is the new Hydra-Matic 6L80 six-speed automatic transmission. It has a wide, 6.04:1 overall ratio including two overdrive gears that helps deliver an excellent balance of performance and fuel economy. It is similar to the six-speed paddle shift automatic transmission introduced on the 2006 Corvette, but is been tailored for the heavy-duty requirements of SUVs and trucks.
There are no compromises with the 6L80 transmission it delivers great performance and enables improved fuel economy on the highway, all with smooth, almost imperceptible operation, said Jeff Baran, chief engineer for six-speed rear-wheel drive transmissions.
The 6L80s six forward gears have smaller steps between them, compared to a conventional four-speed automatic, which bolsters both performance and the feeling of smoothness. Shorter steps between the gears help the transmission quickly find the best gear for the vehicle speed and road conditions, with less back-and-forth hunting on grades a trait that is particularly helpful when towing.
Gen IV small-block details
The Gen IV Vortec V-8 truck engines are built in a variety displacement and power combinations, including versions with aluminum cylinder blocks. All engines share a basic architecture that includes 4.400-inch bore centers the same design foundation on which the original small-block V-8 was developed in the early 1950s. Initial Gen IV engine offerings include:
* 4.8L iron block (RPO LY2), rated at 290 horsepower (216 kw)*
* 5.3L iron block (RPO LY5) with Displacement On Demand technology, rated at 320 horsepower (238 kw)* including E85-capable version (RPO LMG)
* 5.3L aluminum block (RPO LC9) with Displacement On Demand technology and E85 capability, rated at 320 horsepower (238 kw)*
* 6.0L iron block (LY6) heavy-duty engine with variable valve timing, rated at 350 horsepower (261 kw)*
* 6.0L aluminum block (L76) with Displacement On Demand technology and variable valve timing, rated at 355 horsepower (264 kw)*
* 6.2L aluminum block (L92) with variable valve timing, capable of 380 to 400 horsepower (283 to 298 kw)*
All Gen IV Vortec engines are designed to provide improved fuel economy and reduced emissions, compared to previous-generation small-block V-8s. The 5.3L engines with Displacement On Demand (DOD) technology, for example, provide up to seven percent fuel economy gains.
The new engines also meet more stringent emissions standards. In fact, compared to truck engines of a decade ago, the Gen IV Vortec engine family is approximately 90 percent cleaner. Cast iron exhaust manifolds matched with dual close-coupled catalytic converters help reduce cold-start emissions, which is the largest source of vehicle emissions.
Revised cylinder block
Aluminum-block Gen IV-design engines debuted as the LS2 in the 2005 Chevy Corvette and SSR, as well as the 05 Pontiac GTO. The new Vortec truck engines share the basic design of these versions, but are engineered for the specialized needs of truck applications. Like the LS2, the new Vortec engines have a revised cylinder block design that features new, externally mounted knock sensors. They were moved from the valley area to enable Displacement On Demand technology and other advanced systems.
Some Gen IV Vortec engines use aluminum cylinder blocks, which offer reduced mass an attribute that supports improved vehicle weight distribution and slightly improved fuel economy. The aluminum blocks are virtually identical to their iron counterparts, including a deep skirt design that incorporates cross-bolted main bearing caps and a structural oil pan. All engines, except the 6.2L L92, use a proven iron crankshaft design and highly durable reciprocating components. The high-performance 6.2L L92 uses a forged steel crankshaft.
The block for the 6.2L engine features a crankcase windows vents that help improve bay-to-bay breathing. This reduces pumping losses and supports the high horsepower output of the high-performance engine. A new, 58X ignition system and a more powerful, E38 ECM are integrated on all engines.
The 58X ignition system uses a unique crankshaft wheel and sensors to provide the new, 32-bit E38 ECM with more immediate information on the crankshafts position during rotation. In turn, this allows the controller to adjust ignition timing with greater precision, which optimizes performance and economy. Engine starting also is more consistent.
Displacement On Demand (DOD)
Some 5.3L and 6.0L engines are equipped with GMs fuel-saving Displacement On Demand technology, which can temporarily shut down the combustion process of half the engines cylinders under certain driving conditions to save fuel. GM was the first manufacturer to offer this fuel-saving technology on trucks. On the new full-size SUVs, it works with other attributes, such as improved vehicle aerodynamics, to maintain GMs fuel economy leadership in the segment.
A sophisticated engine controller determines when to deactivate cylinders, allowing the engine to maintain vehicle speed in lighter-load conditions such as highway cruising. The process is seamless and virtually imperceptible. When the cylinders are deactivated the engine effectively operates as a V-4, with alternate cylinders on each cylinder bank disabled. The engine returns to V-8 mode the instant the controller determines the vehicle speed or load requires additional power. The key to DODs efficiency and virtually imperceptible operation is a set of special two-stage hydraulic valve lifters, which allows the lifters of deactivated cylinders to operate without actuating the valves.
The valve lifters have inner and outer bodies, which normally operate as a single unit. When the engine controller determines cylinder deactivation conditions are optimal, the outer body moves independently of the inner body on the disabled cylinders lifters. The outer body moves in conjunction with camshaft actuation, but the inner body does not move, holding the pushrod in place. This prevents the pushrod from actuating the valve, thereby halting the combustion process. Solenoids in the engine lifter valley operate to deliver high-pressure oil to the switching lifters, activating a release pin to separate the inner and outer bodies. Oil circulation and pressure do not vary, regardless of the engines operational mode. Lifter design and pushrod length are the same for every cylinder, but camshaft lobe profiles differ for cylinders designated to be deactivated.
The engines electronic throttle control (ETC) also is used to increase manifold pressure in V-4 mode so that the engine can maintain a V-8 torque load.
Variable valve timing (VVT)
Variable valve timing (VVT) is a standard feature on 6.0L and 6.2L engines; it helps optimize camshaft timing to improve low-rpm torque and high-rpm horsepower. The introduction of variable valve timing through the unique dual-equal cam phaser is the industrys first application of VVT on a mass-produced V-8 cam-in-block engine. The unique dual-equal phaser adjusts the camshaft timing at the same rate for both the intake and exhaust valves.
The system incorporates a vane-type camshaft phaser that changes the angular orientation of the camshaft, thereby adjusting the timing of the intake and exhaust valves to optimize performance and economy, and help lower emissions. It offers infinitely variable valve timing in relation to the crankshaft. The cam phaser vane is attached to the camshaft on the front journal. As driving conditions warrant, the cam phaser system can reduce ignition timing at higher rpm levels to increase power. At lower rpm levels, torque is enhanced with increased timing.
This cam phaser feature was pioneered by GM and introduced on the new 3.5L and 3.9L V-6 engines in 2005 a first for the use of variable valve timing on a cam-in-block engine design. As driving conditions warrant, the cam phasing system can reduce ignition timing at higher rpm levels to increase power. At lower rpm levels, torque is enhanced with increased timing.
Precise camshaft timing is the key to the variable valve timing systems capability to optimize performance. Like the 58X ignition system, cam phasing is directed by the E38 ECM. It relies on data from a camshaft position sensor a target ring with four equally spaced segments that communicates the camshafts position quicker and more accurately than previous systems that used just a single segment. Also, a leaf spring-type tensioner is used on the timing chain to ensure precise tension.
The aluminum-block 6.0L version uses variable valve timing in conjunction with Displacement On Demand technology to bolster fuel economy. With cam phasing, Displacement On Demand technology allows the engine to run longer in fuel-saving four-cylinder mode, while producing instant V-8 power and response as soon as the driver calls for it.
High-flow cylinder heads
The Vortec 6.0L and 6.2L engines offer a significant power level increase compared with previous premium engines, with much of the newfound power coming from high-flow aluminum cylinder heads. The heads are based on the racing-derived cylinder heads of the Corvette Z06s LS7 7.0L engine, including a unique inlet port shape and offset rocker arm design. Airflow of the heads is supported by large 55-mm-diameter intake valves and 40.4-mm-diamter exhaust valves.
The heads use the high-performance technology of the Corvettes LS7 to build efficient power in truck engines, said Meagher.
Vortec 4.8L and 5.3L engines also have high-flow, Corvette-derived heads. They are based on the previous-generation Corvette Z06s LS6 engines cylinder heads and have flow characteristics commensurate with the engines airflow-to-displacement needs. All the Gen IV Vortec engine variants use the same efficient ignition coil packs of the LS2 to light off the air/fuel mixtures that are drawn through the heads.
Quiet, durable operation
All Gen IV small-block Vortec V-8 engines are designed for quieter operation, including:
* Special friction-reducing coating on piston skirts
* Full floating piston pins
* Damping patch on the oil pan (externally mounted)
* Timing chain tensioner
* Quieter alternator
The quiet features of the engines are complemented in the vehicles with stronger engine cradles and mounting systems. These systems help reduce vibrations transmitted through the chassis and would otherwise be felt by vehicle passengers.
Backing the new engines quietness is the assurance of long-lasting performance. The new Gen IV engines were validated under extreme conditions, with dynamometer testing equivalent to 150,000 miles. The Vortec 6.0L iron block heavy-duty engine was tested the equivalent of 200,000 miles.
Some of the stringent durability testing included cycling engines between the peak torque and peak horsepower rpm points the equivalent of towing a heavy trailer up a steep grade for 600 straight hours.
The engines also feature many long-life engine components that can reduce maintenance intervals and costs. The iridium-tip spark plugs, engine coolant, accessory drive belt and sealing gaskets are some of these items. Also, a revised water pump design (introduced on late Gen III V-8s) has improved sealing for increased durability.
E85 capability
Two versions of the Vortec 5.3L Gen IV V-8 are compatible with E85 ethanol-based fuel, which offers a good environmental alternative to gasoline. The engines can run on any combination of gasoline and/or E85 fuel.
A new virtual fuel sensor reduces the cost and complexity of adding E85 capability to the fuel system. The ECM samples the exhaust at the oxygen sensor, and an algorithm determines whether E85 is used, as well as its mixture percentage with gasoline. Its a much simpler, less costly system than previous systems that relied on fuel composition sensors. In fact, the entire system on the engine is simple: only the fuel rail and fuel injectors are different between E85 versions and non-E85 versions.
E85 is a clean-burning alternative fuel made in the United States with homegrown corn and other crops. E85 is largely alcohol, composed of 85 percent ethanol and 15 percent gasoline. The alcohol is produced by fermenting plant sugars. E85 nearly eliminates greenhouse gas emissions from automobiles, is biodegradable, doesnt contaminate the water supply and can be produced from various feed stocks, including grain, corn and wheat stalks, forestry and agricultural waste, and even municipal waste.
Hydra-Matic 6L80 details
GMs new, Hydra-Matic 6L80 electronically controlled six-speed automatic transmission is matched with the 6.2L engine. A higher-capacity Hydra-Matic 4L70-E four-speed automatic is paired with 6.0L engines; 4.8L and 5.3L powertrains are teamed with the Hydra-Matic 4L60-E four-speed.
The 6L80s wide, 6.04:1 overall ratio, including two overdrive gears, allows for the transmissions shorter steps between gears. This enables a steep, 4.02:1 first gear, which provides a very strong launch feel. The two overdrive gears include a 0.85:1 ratio in fifth gear and a 0.67:1 ratio in sixth. With two overdrive gears, engine rpm is reduced by approximately 9 percent at 60 mph a reduction of about 1,350 rpm. Lower engine rpm can bolster fuel economy because less fuel is used. A lower-rpm cruising speed also enhances smoothness and reduces noise heard in the vehicles cabin.
Technical sophistication is exemplified by clutch to clutch operation that reduces complexity and packaging. It also enhances the performance feel of the transmission, as shifts feel more immediate and precise. Clutch to clutch operation is achieved with three planetary gears, three stationary clutches and two rotating clutches. It is a simple, less complex design that enables the six-speed transmission to be packaged in a size not much larger than a four-speed automatic. All forward gear shifts feature clutch to clutch operation.
A new, 32-bit electro-hydraulic control module optimizes the 6L80s performance according to a variety of vehicle inputs, while also enabling features including tow/haul mode, auto grade braking and manual range selection. The controller is integrated within the transmission.
Tow/haul mode is a driver-selectable feature that reduces shift busyness when towing or hauling a heavy load. The feature is complemented by manual range selection or tap-up/tap-down capability which allows the driver to manually select upshifts and downshifts with a button on the column shifter. Auto grade braking is available when the tow/haul mode is selected and the transmission is not in the range selection mode.
*Preliminary, pending certification. A new voluntary power and torque certification procedure developed by the SAE Engine Test Code committee was approved March 31, 2005 . This procedure (J2723) ensures fair, accurate ratings for horsepower and torque by allowing manufacturers to certify their engines through third-party witness testing. GM was the first auto manufacturer to begin using the procedure and expects to use it for all newly rated engines in the future.
* Compatibility brackets protect lower-riding vehicles in crashes
* Safety belt pretensions that activate in rear impact are industry first
* Roof-mounted head curtain side air bags add rollover protection
GMs new 2007 full-size SUVs are designed to be among the industrys safest and most secure vehicles. The vehicles provide a 360-degree perimeter of safety protection and provide increased compatibility with other vehicles.
New features include available roof-mounted head curtain side air bags, which are integrated into strengthened chassis and body structures to provide excellent passenger protection. Stabilitrak electronic stability control with rollover mitigation technology is standard.
These vehicles envelop occupants with a comprehensive safety system that is built from a foundation of segment leadership in safety technology said Gary White, General Motors North America vice president and vehicle line executive for full-size trucks.
GMs full-size SUVs have a heritage of safety innovation. Previous-generation vehicles were the first vehicles in the industry to offer a passenger sensing system to suppress deployment of the front passenger air bag if a child or person of smaller stature is detected. GMs full-size SUVs also were first to offer dual-stage air bags, standard four-wheel antilock brakes and a standard electronic stability control system.
In the new models, comprehensive safety encompasses crash avoidance, occupant protection and post-crash care. The safety portfolio features three linked avenues of protection: vehicle structure and dynamics; occupant safety features, and driver control features.
It starts with a stronger frame and body structure. Crash avoidance, for example, is bolstered through enhanced driver control dynamics, such as wider front and rear tracks, as well as more responsive suspensions including a new coil-over-strut front suspension design and new rack-and-pinion steering. StabiliTrak electronic stability control with roll-over mitigation is standard on all models.
Here are the safety highlights of GMs 2007 full-size SUVs:
1. Vehicle structural and safety dynamics :
* Body-on-Frame (BOF) structure with comprehensive use of high-strength steel
* Stronger, stiffer frame, including all-new front bay design for improved crush dynamics and provisions for improved vehicle-to-vehicle compatibility
* Wider front and rear tracks enhance stability, handling and lower the center of gravity
* Enhanced body structure for superior occupant protection
1. Occupant safety and security :
* Standard dual-stage drivers front air bag and dual-stage outboard-front passenger air bag with passenger occupant detection system
* Available roof-mounted head curtain side air bags with tethers and roll-over protection for all seating rows
* Front safety belt pretensioners
* A 360-degree sensing system for fast, accurate impact analysis and airbag deployment/seatbelt pretensioner activation
* Enhanced head-impact protection
* High-retention front seatbacks help restrain front seat passengers during a collision
* Three-point safety belts in all seating positions (except base vehicle front bench center seat position)
2. Driver control :
* Enhanced driving dynamics, including standard StabiliTrak electronic stability control with rollover mitigation
* Autotrac active transfer case
* Larger-capacity four-wheel disc brake system
* Standard door child security locks
* Standard four-channel ABS and traction control
* Standard tire pressure monitoring system
* Standard Passkey III anti-theft system
* OnStar system Gen 6
* Available locking rear differential
* Available Ultrasonic Rear Parking Assist
* Available rear-view camera system
* Available remote start capability
* Available rain-sensing wiper system
Vehicle structural and safety dynamics
The vehicles are built on a stronger and stiffer, fully boxed frame that is designed for improved crash-energy management. The front frame section, for example, has improved crush dynamics that provide the equivalent of 17.7 inches (450 mm) of additional crush space in vehicles that are only approximately 3 inches (76.2 mm) longer than their predecessors. The frame also is designed for improved vehicle-to-vehicle compatibility.
The all-new, fully boxed frame features hydroformed front and rear sections, as well as strategic placement of high-strength materials. The frame also features more reinforcing cross members than the previous-generation models, as well as stronger mounting brackets in key areas. The hydroformed front section frame rails have a wall-thickness of approximately 3.2 mm and are straighter with a more consistent cross-section than the previous-generation frame a design that delivers improved axial crush performance. Also, the new frame is 49 percent stiffer than the predecessor, which helps resist bending or twisting during a crash. (See Chassis Systems section for more information.)
The front rails of the frame are designed with enhanced vehicle-to-vehicle compatibility with smaller or lower vehicles during a crash. Compatibility brackets located on the forward position of the lower front frame rails are designed to buckle in a frontal or offset collision, reducing the motion of the frame into the smaller vehicle. The location of the brackets meets all car structure heights. GM crash-tested the tallest of the SUV models with some of the shortest cars on the road for crash compatibility.
Along with the frame, the upper body structure is designed to manage the energy of a crash, including improved side-impact and rollover performance. Strategic placement of high-strength steel throughout the frame and body structure provides additional support and helps maintain passenger compartment integrity during a crash.
The 07 SUVs body structure enhancements also include:
* A new A-pillar reinforcement made of high-strength steel that resists buckling
* High-strength steel roof-rail reinforcements on both sides of the B-pillar where they meet the roof rails contribute to improved roll-over performance
* A diagonal brace made of high-strength steel located beneath the driver and front passenger toe pan provides reinforcing strength for the vehicle and lower torso protection for passengers
* An all-new, single-piece rear D ring offers increased dimensional accuracy and reinforcing structure
* An enhanced front door hinge box adds strength to the forward section of the front door D-ring which helps reduce deformation during a crash
* Stronger knee bolster brackets (welded to the instrument panel cross beam) are designed to withstand higher loads during frontal impacts
* A new Z bracket adds strength to the area where the front-of-dash section of the body structure meets the floor pan, as does structural adhesive applied to the same area
The strength of the frame and body structure, extensive math modeling and internal crash tests contribute to GMs expectation that the new SUVs will be among the segments top performers in frontal barrier and frontal offset crash tests.
Other features that contribute to the SUVs strong performance during a crash include:
* Impact beams Front and rear impact beams are designed to absorb low-speed crashes and minimize vehicle damage. A more severe crash will cause the energy-absorbing bumper beam to crush. There also are two side-impact beams in each door.
* Passenger head protection Energy-absorbing foam padding and trim on the A-, B- and C-pillars, as well as the roof rail, are designed to spread the energy of a crash by crumpling and crushing on impact. The headliner also contains energy-absorbing material.
* Seat safeguards High-strength front seatbacks provide restraint during a rear-end crash. There also is a crushable pan between the seat frame and seat cushion the pan will crush to absorb energy in the case of a high load.
Occupant safety and security
Air bags: Dual-stage driver and outboard front passenger air bags are standard on all models. Children and smaller-stature front passengers are protected with GMs passenger occupant detection system. Roof-mounted head curtain side air bags are available on all models. These air bags inflate to restrain outboard passengers in all seating rows and are equipped with special tethers that hold the bags in place for several seconds for increased rollover protection and passenger containment.
The air bag systems sensors determine the severity of a crash, indicating whether the primary stage of inflation or the primary and secondary stages are required for maximum protection. The sensors are located at the front of the vehicle, on the radiator support beam.
In the event of a side-impact collision, the head curtain side air bags act like a protective curtain, unfolding from the roof rail between the A- and D-pillars in three-seating row vehicles and A- to C-pillars in two-row configurations. The first- and second-row positions are restrained by a larger side air bag and the third row has a dedicated air bag. Each side air bag has its own dedicated inflator for optimized fill rates into each curtain.
The roof-mounted head curtain side air bag system incorporates one of the segments first rollover indication sensors, which is located in the vehicles center tunnel. The sensor monitors the vehicles angle variance from level. If the angle indicates an impending rollover, the side air bags will deploy to provide an extra measure of occupant protection and containment. In this instance, the side air bags stay inflated longer than during a side-impact collision, because rollover incidents may last longer and the inflated air bags help keep occupants inside the vehicle.
Occupant protection from secondary impacts also is a feature of the roof-mounted head curtain side air bags. Based the severity of the event, the bags curtains are deployed whenever the second stage inflation of the frontal air bags is triggered. GMs safety engineers reasoned that a collision severe enough to trigger both stages of frontal air bag inflation is likely to cause a secondary collision. In this instance, the air bags deploy and remain inflated for several seconds following the initial collision, ready for a possible second impact.
Front safety belt pretensioners and rear safety belt features: Front safety belt pretensioners are standard on all models. In the event of a crash, they take up slack in the safety belt webbing to help secure the passenger in the seat and prevent him or her from submarining during the crash. It also helps to hold the passenger in position, so deceleration is at the same, slower rate of the vehicle and not a more abrupt stop.
The pretensioners are activated by a sensor, which triggers a pyrotechnic device that almost instantly reduces slack in the belt webbing. The safety belts are equipped with low-friction D-rings and low-effort retractors, so there is minimum pressure on the occupant, making the belts more comfortable to wear. Also, the pretensioners will activate in a rear-end crash an industry first in GMs full-size SUVs.
Second- and third-row seats have three-point safety belts in all positions. An added feature is an available comfort guide on the outboard seatbelts. This device has an elastic cord that helps to properly position the shoulder belt on smaller-stature occupants. The second- and third-row seats also come equipped with LATCH system child seat anchors, for both top tethers and lower latches, to simplify installation of child seats with these features. These anchors, which are secured to the body structure, are provided in the rear outboard seating positions.
Sophisticated sensors: The new SUVs are equipped with the segments most comprehensive system of crash impact sensors, which work together to provide 360 degrees of sensing tied to the central Sensing Diagnostic Module (SDM). This provides faster, more immediate data that is used to activate the vehicles numerous air bag safety features. The sensors include:
* Two forward sensors located on the frames most forward cross member measure deceleration crush, enabling SDM decisions in less than 10 milliseconds
* Four side-impact sensors one on each side-door beam provide more rearward sensing of side impacts than previous models
* A roll-over sensor that continually measures the vehicles pitch angle and signals the SDM if the angle indicates in imminent roll-over
* Rear sensors that detect rear-end impacts and trigger the safety belt pretensioners
Driver control
While designed to help protect passengers in the event of a crash, the new 2007 full-size SUVs also have features designed to avoid or lessen the chance of a crash. This starts with a wider front and rear track, which helps provide a more secure driving feel and a lower center of gravity. Also, the improved responsiveness while driving delivered by the new coil-over-shock front suspension, enhanced five-link rear suspension and new rack-and-pinion steering system provides the driver with a heightened feeling of control.
StabiliTrak electronic stability control: GMs sophisticated StabiliTrak electronic stability control system is standard on all 2007 full-size SUV models. Partnered with the new brake system and four-channel, four-sensor electronic brake controls, the system provides more precise, controlled ABS stops, as well as enhanced traction/yaw stability.
The Stabilitrak system has new rollover mitigation technology. Rollover mitigation adds software algorithms that use Stabilitrak sensors to proactively predict vehicle tip up on a flat road surface, and applies brake force to the outside front and rear wheels in order to reduce lateral force in the vehicle. This brake force intervention can help reduce the likelihood of a rollover in certain circumstances including fish hook maneuvers that involve sudden and rapid back-and-forth steering.
On 4WD models, StabiliTrak uses brake control to precisely manage the speed of each wheel as well as torque across the front and rear axles. On 2WD models, the system precisely controls the speed at each wheel and manages side-to-side torque on the rear differential. Individual brake sensors at each wheel provide signal the control module, enabling it to aggressively adjust brake pressure. However, traction is controlled by transferring torque across the rear axle rather than front and rear axles, as in 4WD models). When the vehicle is on a slippery surface, the traction system increases torque to the rear wheel that has the most traction.
On 2WD and 4WD models, the vehicle brake system provides torque-biasing to enhance traction and engine management as required to assist in controlling traction and yaw stability. The Autotrac transfer cases control algorithm has been integrated with the StabiliTrak and ABS systems to provide enhanced vehicle stability by managing the front-to-rear torque distribution.
StabiliTrak is always on and fully functional. It is automatically enabled, providing full stability, traction and ABS control, whenever the vehicle operates in forward gears. The system intervenes when it senses one or more of the wheels slipping or when the vehicle is not following the drivers intended path. It detects slippage during braking or acceleration and automatically adjusts individual wheel brake pressure, engine torque and, on 4WD Autotrac models, adjusts front to rear drive torque distribution, as required, to achieve optimal control.
Autotrac: Four-wheel drive models feature the Autotrac active transfer case, which helps keep the vehicle sure-footed in slippery driving conditions. When shifted to the Auto mode, Autotrac engages all-wheel drive traction automatically. The vehicle operates in rear-drive mode, but torque is automatically split between the front and rear wheels when the system senses all-wheel drive traction is needed. The process is smooth, quiet and almost undetectable.
New, segment-leading pre-emptive controls allow the Autotrac system increase the torque to the front axle on slippery roads prior before slippage occurs. This can increase control because the system anticipates rather than reacts to slippery conditions. Autotrac also is integrated with StabiliTrak, which now incorporates the signal from one of Autotracs slip-detection sensors to provide another measure of input to the stability control system. This new input allows StabiliTrak to operate more efficiently.
An available locking rear axle also helps provide sure-footed traction, particularly when towing. When rear wheel slip is detected, the rear axles lock to turn at the same rate, providing all available torque to both wheels. This is helpful for special circumstances, such as pulling a boat and trailer up a launch ramp.
New four-wheel disc brake system: A larger-capacity, four-wheel disc brake system with a new, four-channel ABS is designed to provide the new SUVs with superior stopping capability and the segments best braking feel. ABS is standard on all models, along with a full-function traction control system (traction control only on 2WD models). The headlining elements of the new brake system include larger-diameter front and rear disc rotors and new, stiffer brake calipers.
The front rotors measure 13 inches in diameter (330.2 mm), an increase of 1 inch (25.4 mm), or 15 percent larger. The front rotors also are thicker, with large cooling vents, providing enhanced performance and durability. The cast iron, dual-piston front brake calipers are 50 percent stiffer than before, which reduces the tendency for flexing during hard or prolonged braking. The stiffer calipers, along with dual pistons, contribute to a more direct and stronger brake pedal feel.
Rear brakes feature standard vented discs that measure 13.5 inches (342.9 mm), an increase of 0.5 inch (12.7 mm) approximately 7.5 percent larger. A revised single-piston rear brake caliper design contributes to reduced brake noise and more immediate braking response. Both the front and rear brakes use new, non-asbestos brake pad linings that can deliver up to 40,000 miles of performance during normal use.
The new brakes are complemented by a more robust, twin piston brake application system, including a larger master cylinder and active brake booster. Engineers tuned the application system to optimize the pedal feel and brake system responsiveness. It requires less pedal pressure to provide a more immediate brake response, delivering a dramatically improved feel.
A next-generation Bosch 8.0 ABS system is standard on all 2007 full-size SUVs. It has more precise valve control the requires less cycling of fluid from the brake master cylinder, resulting in reduced noise and enhanced braking feel when ABS is activated during braking. The new ABS system also is less complex and has reduced mass when compared with the previous system.
Full-function traction control uses the ABS system to regulate brake pressure to help provide enhanced traction for 2WD vehicles.
Ultrasonic Rear Parking Assist: The new optional Ultrasonic Rear Parking Assist system provides visual and audible warnings of objects behind the vehicle. The system operates when the vehicle is in Reverse, using fours sensors located at the rear of the vehicle. The new system is available in conjunction with a new, optional rear-view camera system, the first offered in a GM vehicle.
Rear-view camera system: The available rear-view camera system can be ordered with the optional navigation radio system. The camera provides a view of the rear of the vehicle not easily seen, even with the outside or inside rearview mirrors, allowing the driver to check for persons or obstacles directly in the path of the vehicle. It also assists with parallel parking or trailer backing. Drivers should still inspect around their vehicles for objects or playing children.
A large, clear picture of the cameras field of view is available on the navigation radio screen. The rear-view camera also works with the Ultrasonic Rear Parking Assist to provide an audible proximity reference to items in the cameras view. If an rear parking assist sensor detects a person or object, it alerts the camera.
The camera only functions when the vehicle is shifted into Reverse. For convenience, it will stay on for a calibrated length of time determined partly by vehicle speed after the vehicle is shifted into Drive. The camera is mounted in the license plate surround bracket for an integrated styling appearance. It provides approximately 20 feet (6.1 meters) of viewing distance behind the vehicle.
OnStar Generation 6: All models come standard with the OnStar Generation 6system, including a one-year subscription to the Safe & Sound plan. The OnStar service includes the General Motors Advanced Automatic Crash Notification (AACN) system, making crash data available to emergency services to potentially dispatch the appropriate life-saving personnel and equipment to crash scenes faster. If the vehicle is in a crash that activates an airbag, the OnStar system automatically notifies an OnStar Advisor who will check on the occupants or summon emergency help if necessary. OnStar also can assist authorities in locating a vehicle if it is reported stolen and provides remote door-unlocking service
Remote starting system: A factory-installed remote vehicle starting system is available on most models a first for GMs full-size SUVs providing customers with the convenience of starting the vehicle during inclement weather or other situations. The system has up to a 200-foot (61 meters) range and offers automatic climate pre-conditioning to warm or cool the vehicle prior to entry. On cold mornings, for example, the heat and defroster will be automatically turned on, even if the operator had last used the controls in a vent position.
The remote starting system is optional on some models and standard on others. Also, vehicles not originally equipped with the system are pre-wired at the factory so that the remote starting feature can be installed and activated by a GM dealership service department.
Tire pressure monitoring system: A revised and easier-to-use tire pressure monitoring system is standard on all models, providing drivers with peace of mind and contributing to a safer driving experience. The system alerts drivers via a signal on the instrument panel driver information center if a tires inflation status requires attention. In fact, the system sends a message to the information center each time the vehicle is started as part of a routine operations check. The driver also can use the information center to check the pressure of each tire. The pressure monitor sensors can detect air pressure differences to within one pound of the other tires.
Rain-sensing wipers: Available on some models is an optional rain-sensing windshield wiper system that automatically activates the wipers when precipitation is detected.
An infrared sensor located on the windshield (behind the inside rearview mirror) is used to detect raindrops. If rain or other precipitation is detected, the system signals the wipers to operate and adjusts wiper speed based on the intensity of the precipitation.