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Taken from Ultimatecarpage.com:
Progressing through the various classes during the 1980s, privateer racer Jim Miller stepped up to IMSA GTP in 1989. He quickly discovered that his 'off-the-shelve' Chevrolet-engined Spice was no match for the works Nissans and Toyotas. To bridge the gap, Miller first asked engineer Bob Riley to upgrade his Spice ahead of the 1990 season and then commissioned Riley to design a new car from scratch. Tasked to construct the GTP machine was Gary Pratt formerly of Protofab, which had developed the Riley-designed Corvette Trans-Am car previously raced by Miller.
Riley had already been walking around with the design for a mid-engined GTP car for quite some time but until Miller approached him had found no willing partners. Downforce was the key word in IMSA racing, more specifically ground-effect downforce generated by massive tunnels in the floor. Accordingly, Riley designed the new GTP car to have the largest underbody permitted by the regulations. The GTP machine boasted a carbon-fibre composite monocoque with in-board suspension front and rear to free up even more room for the tunnels. It was clothed in an unusually blunt body with slab sides.
Originally, Miller had intended the car to be powered by a development of Judd's V10 engine, which was presumed to be capable of upwards of 1,000 bhp. The IMSA regulations, however, favored "Stock-block" engines over the more exotic purpose-built engines. This prompted Miller to turn to his longtime supplier General Motors for a tried and trusted small block V8. Displacing just under 6.5 litre, the Chevrolet engine was further developed by Katech and equipped with the latest engined management system supplied directly by General Motors. Good for around 800 bhp, the small-block V8 was mated to a five-speed Hewland gearbox.
Dubbed the Intrepid RM-1, a pair of the new GTP racers was constructed by the newly established Pratt & Miller outfit early in 1991. Riley's focus on the ground-effect aerodynamics had paid off as the car produced close to 4,000 kg of downforce and it was capable of cornering forces of up to 3.5 G. Entered for Wayne Taylor, the first example impressed on its early March debut debut at West Palm Beach. The South African qualified sixth and finished the race in second. Taylor subsequently qualified on pole in Miami but failed to finish due to a half-shaft failure. In May, the second car was ready and entrusted to Tommy Kendall.
During the subsequent outings Taylor and Kendall impressed particularly during qualifying. After a string of strong finishes, Taylor scored the first IMSA GTP victory for the Intrepid at New Orleans after starting seventh. At Watkins Glen, the unprecedented downforce levels caused a suspension failure, which sent Kendall's Intrepid into the wall at very high speed. He was lucky to walk away but it meant the team was down to one car for the remainder of the season. Taylor continued to impress in qualifying but no more victories were scored.
Ahead of the 1992 season, two additional cars were built; one for Tommy Kendall, while the other car along with the surviving 1991 Intrepid were sold to Tom Milner Racing. In a quest to secure more support, the cars were renamed Chevrolet GTP but it was to no avail. During the season, the cars lost competitiveness. Among the problems were the mandatory switch to steel brakes from the carbon-composite discs previously used and the lack of top speed due to the considerable drag created by the high downforce levels. Podium finishes early in the 1992 season were the rare highlights of that year.
The cars were raced into the 1993 season but with little success. Despite its potential and the unprecedented levels of downforce generated by the Intrepid, ultimately only one victory was scored. The project's legacy is altogether more impressive as Bob and his son Bill Riley would go on to use a derivative of the design to create the highly successful Riley & Scott prototype races, while the Pratt & Miller partnership continues to this day, most famously running the Chevrolet Corvette works program.
Engine:
Configuration: Katech / Chevrolet 90º V8
Location: Mid, longitudinally mounted
Construction: aluminium block and head
Displacement: 6.5 liter / 396.7 cu in
Valvetrain: 2 valves / cylinder, OHV
Fuel feed: Fuel Injection
Lubrication: Dry sump
Aspiration: Naturally Aspirated
Power: 800 bhp / 597 KW
BHP/Liter: 123 bhp / liter
Drivetrain:
Body: Carbon-Fibre composite
Chassis: Carbon-Fibre composite and aluminium honeycomb monocoque
Suspension (fr/r): double wishbones, push-rod actuated coil springs over dampers, anti-roll bar
Steering: Rack-and-Pinion
Brakes: Ventilated discs, all-round
Gearbox: Hewland 5 speed Manual
Drive: Rear-wheel drive
Dimensions:
Weight 850 kilo / 1873.9 lbs
Length / Width / Height: 4801 mm (189 in) / 1981 mm (78 in) / 1041 mm (41 in)
Wheelbase / Track (fr/r): 2794 mm (110 in) / N/A / N/A
Wheels (fr/r): 13 x 17 / 15 x 17
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