Dan
Premium
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1/4 Mile Transmission Tuning for Dummies(Fully Illustrated)
- Thread starter Master__Shake_
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- New york
- IvIaster__Shake_
- 308
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- Angels_Demon83
F1 Racer
You have to buy the fully customizable transmission. As for the ballast it should be there.
what i would like to know is if you have a 4x4 and a ton of horsepower why not just fiddle with the limited slip. Wouldnt having high LSE eliminate wheel spin with enough weight or is it pratical with 4x4 to set high LSE and not worry about whether you should start in 1st or 2nd gear when pushing for acceleration. I know irl 4wd in drop gear is gonna bog without having horsepower and torque to componsate but the tracking is so much more effective on slick pavement when a jeep liberty sport goes toe to toe with a light weight mitsubishi eclipse pushing 300+ horses under the hood because all its wheels do is spin, not to mention its a manual. Plus fyi (non-professionals anyway). Any comments?
- 1,835
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- IvIaster__Shake_
Unfortunately, the LSD in the game does nothing for straight-line acceleration, only corner acceleration, so its useless for drag racing. The only thing that works for 4WD is torque % for front vs rear wheels, and the best ratio I've tested is 45/55. Even this on high horsepower 4WD cars will cause some wheelspin, but wheelspin is better than bogging, so the game physics once again fail for drag racing. I really wish they'd consider adding drag slicks for GT6.
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- heresduke
So everything in the front low n everything in the rear high is not a good suspension right. Keep it balacned. Its a ?c-l25
- 5,588
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- ryzno
Depends on the drive train.
Usual Ride Height for specific car layouts:
- RWD
Max. traction: Front height depending on car, theoretically at lowest, but even for 1/4mile often somewhere in the middle; rear max.
Low rear is only needed for high downforce cars and if you tune for longer distances (e.g 3k) - FWD
Pretty much always front at lowest and the rear all the way up. This is valid for all distances, except maybe 10k (with certain cars) or cars with massive downforce. - AWD
Front low and rear up is mostly the way to go, when max. grip is your main goal (mainly for 1/4).
But sometimes, namely for long distances, a car is just (or at least close to be) slammed to the ground, which can have some positive effects (slightly longer first possible, smaller tendency to bog, less shiftlag, better top, etc.). "Surprisingly" (not really though), it is often beneficial to have the front slightly higher than the rear if you tune for 3k.
From here. https://www.gtplanet.net/forum/threads/the-drag-tuning-bible-v4-1-september-2012.235213/
- 17
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- heresduke
- 68
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- vid_speed
i have problem with mercedes c63 amg 870 horse power 1400 kg.in first gear when i start turbo needs a lot to achive full powerThis is the complete newbie's guide to tuning your transmission for the 400m(1/4 mile) run either at Indy Road Course or Special Stage Route X. To tune your transmission, purchase custom transmission in the tuning section of your car options.
Powerband
The first thing you must do, before you start tuning the transmission of any car, is look at your powerband and what drivetrain the vehicle is using. Different drivetrains, such as 4-wheel drive(4WD), Front Wheel Drive(FF or FWD), and Rear Wheel Drive(FR, MR, RR, or RWD), all require different setups to maximize acceleration. In this guide we'll go over Mid-engine, rear wheel drive, as well as 4-wheel drive.
This is the powerband information for a popular drag car, the Ford GT No-Stripe:
And this is the powerband information of another popular drag car, the Audi Lemans Quattro:
You may look at them both and think, "I don't see a lot of differences aside from the lines." In some aspects that's correct, because both cars have similar power and power to weight ratios, but that's where their similarities end. 4-wheel drive cars launch hard from the line, whereas rear-wheel drive cars have tirespin at launch but great top-end pull in the backstretch of the 400m.
To determine what the best gearing setups for these cars, take into account peak torque location & torque curve after the peak, peak horsepower location, where the lines intersect, and how sudden horsepower drops after the peak as well as general horsepower before the peak. These all play roles in setting up the perfect transmission.
Shiftpoints
Now that you've looked at all of these points of interest, lets draw some conclusions from them all. Both of these cars make peak horsepower at roughly 6800 RPM. The Quattro makes torque later on in the powerband, while the Ford GT makes it sooner. RWD cars commonly make more torque in the lower RPMs, but there are quite a few exceptions to this. Torque and Horsepower intersection is more to do with launch, so we'll cover that later.
In order to determine where you want to shift the car, you want to find the highest average power throughout the peak. Basically, keep the car making as much horsepower as possible the entire 400m run. With good tuning of gears, you can achieve this and obtain good times - possibly high leaderboard positions.
Also when you shift, depending on the setup, the next gear may or may not put you under the maximum power you want to be at. In these next examples, the first red line in the curve represents where the gear will start out after shifting, and the second represents at what RPM to shift into the next gear.
Here are two possible shiftpoints for the Ford GT:
Shiftpoint #1 is a common shift by most inexperienced racers, shifting at approximately peak horsepower. It's not a bad shift by any means, this car supporting a nice torque curve, and it doesn't lose a lot of power. Shiftpoint #2 is the better option, which keeps the vehicle at maximum power throughout the run. You will also want to set the transmission up to come across the finishline at roughly peak horsepower or slightly after - only tweaking will give you a definitive answer on that.
And here are two possible shiftpoints on the Lemans Quattro:
Shiftpoint #1 is also the beginners choice in shift, shifting at the peak horsepower. However, in this example, the bottom of the shift puts the car into very low horsepower - which is bad. The torque will not replace raw horsepower in this formula, and you will be left struggling for power between shifts. Shiftpoint #2 provides maximum power as well as the peak torque for a short time, which will keep your momentum going until the next shift.
Transmission Flip
Transmission Flip has been discussed in several other threads, so I will just touch base on it here, but if anyone has any questions - feel free to PM me and I can discuss it in more detail. Flipping the transmission is just that - flipping the gear ratios over onto a brand new final gear; meaning they will either increase or decrease without overall top speed changing.
In order to successfully flip the transmission, you will need to first set the final gear ratio to choose your top speed and ratios for your specific drivetrain. Once you do that, you either raise or lower the top speed slider to set your new permanent gearsets. I say permanent because they will stay at those fixed gears until another top speed is selected via the slider.
For front wheel drive, mid-engine rear-wheel drive, or front engine, rear-wheel drive, you will want to slide it closer to the left to get gears that can be stretched. Also, higher powered 4WD cars can do this to a certain degree. Lower powered 4WD cars will want to slide less to the left - exact numbers are determined by how much power the car has and the weight of the car.
To stretch the gears in a RWD car such as the Ford GT, raise the final gear ratio to roughly 1.000 higher than the minimum, then slide the top speed slider all the way to the left, then proceed to move the final gear slider back to its minimum. This will "stretch" the gears with the best possible ratios for a harder launch.
Too much stretching may cause the car to bog, so play around with the final gear & top speed sliders until you find one that best suits your car. You will also want to get the top speed in the top right corner to roughly 15-20mph above what you will be hitting at the end of the 400m, more if your car makes peak horsepower lower in the powerband.
Transmission Setup
Your first 3 gears in the transmission will be crucial for getting a good launch and keeping momentum going throughout the entire run. In lower powered RWD or FWD cars, you'll want to move 1st gear all the way to the left, then move 2nd gear slightly to the right in order to create less "shift lag". Shift lag is the car bogging, juttering, bouncing, or anything other than a fluid motion of the car moving throughout the shift. 3rd gear will be mostly to the right but not all the way. Then, in most cases, the last 2 or 3 gears will be all the way to the right to keep shift lag to a minimum as well as maximize the acceleration.
In high horsepower RWD cars(and low weight FWD), a short-shift to 2nd may be neccessary and, in extreme cases, a 2nd gear launch or even a 2nd gear short-shift to third will be needed. You can stetch the transmission to make it launch in first, but the top speed will be way too high for you to ever hit your final gear in the 400m and therefore pointless in this regard.
This example is the Ford GT I've shown earlier, with a 2nd gear launch setup. The red arrows and big red blobs represent possible areas where the gears should be set to minimize shift lag:
Now 4WD is a completely different animal. Higher horsepower 4WD transmissions seem to like similar setups to RWD but with varying ratios in order to maximize their amazing off-the-line grip. Lower horsepower 4WD like lower ratios on 1st and 2nd gears, so they grip quickly and lessen bog.
Here is an example of the Lemans Quattro with more red hints. This is, by far, not the best transmission setup for it, but it is a good base setup:
This setup is only good with high horsepower 4WD such as the GTR and the Lemans. For lower 4WD cars, such as the Mitsubishi Evo or the Subaru WRX, you'll want a lower top speed and stretch the last 2-3 gears out while keeping 1st & 2nd gears low to get a quick launch and get momentum quickly.
Finishing touches
In order to make a fluid-movement transmission, you'll want a good gear curve after the launching gear. What I mean by this, is minimize or completely remove shift-lag altogether. This is done by keeping the next gear after launching gear close to minimize the gap. And then the next close as well, then the rest of the gears will follow suit.
Here are examples of what I mean. They should form a line from 2nd(or 3rd) to the final gear, although sometimes for the fastest times they may need to be individually tweaked.
Lemans Quattro:
Ford GT:
Launch
And this is it - you've prepared your entire car for this one moment. Launches can be summed up in 2 ways - Route X launch and Online Launch.
Route X launch refers to hitting a certain RPM at the launch when the timer runs out, and hitting that RPM causes the quickest launch from the line resulting in the best overall time. This can only be done in this mode, and is useless for online racing. But, in order to get the fastest times, this is used to cut nearly .050 from your full-throttle launch, sometimes more. This is also where the torque & horsepower intersection come into play. I'd like to say 7 or 8 times out of 10, that is the best RPM to launch the car at. With each car it varies, but that's usually a safe bet. Underpowered FWD & 4WD cars have a low intersection so it probably won't work for those, but you can still try.
Online launch refers to the full-throttle launch used in online play when racing against other people. In order to tune for this type of launch, simply run full-throttle all the time in Route X and, whichever gearing works better that way, will work better for online. Some gearing methods that work good at the Route X launch will bounce off of the rev-limiter online and slow your launch - usually making you lose the run.
Summary
And that's basically my personal method to the madness. I know other people use different methods for their transmission; I've found these work the best for me. I will not discuss my times for these individual cars, but they're ranked decently on the leaderboards. And, in regards of people begging openly in the forums for tunes, please try it yourself before asking. You have all of the information here to create your own tune that you can be proud of. Thanks for reading.
Additions/Improvements
Shortshifting
This is a topic not often covered and can be confusing to some that have never used it before. Short-shifting is basically a premature shift into the next gear, causing the RPMs to drop slightly in exchange for more traction and a longer gear to ride for the launch. It can be tricky to execute if not done at the right time, or set up the correct way.
The reasoning behind this shift style is simple - you cannot start in 2nd gear without major bogging or hesitation, but 1st gear revs higher than peak horsepower.
Here is an example I used for a front wheel drive car:
This is a lightweight FWD car with roughly 400 horsepower. Notice how 2nd gear is extremely close, noted by the red arrows. Also, 3rd gear must be close to 2nd to act as the "first" shift off of the launch. It's critical that the gears are arranged correctly to keep shift lag at a minimum.
Gearing ratios are set up with 1st gear all the way to the left, 2nd gear somewhere between 70-100 clicks to the right from starting position(depending on ratios of transmission, more may be neccessary). 3rd gear is roughly .100 from the right, judge it by setting the rest of the gears to the far right and set up a good gear angle.
When you go to execute the launch, use whichever method you normally use then, when you come near redline(or above peak horsepower, whichever comes first) shift into 2nd immediately. You will see RPMs either hover at the current position, slightly bog, or continue to slowly increase. This is where you tweak 2nd gear for optimum acceleration in the short-shift. If you're bogging a lot in the shift, you'll want to move 2nd further to the right and may also need to reflip your transmission for better ratios if its too much for the car to handle.
Super Shortshifting
Extreme cases of horsepower, lightweight vehicles, or both require extreme measures - a short-shift into 3rd. This is executed similar to a normal 2nd gear launch, but requires a shorter 3rd gear for the shift. Then also a shorter 4th to compensate for any shift-lag when shifting from 3rd.
Here is an example used from my McLaren F1:
The gear angle is very shallow because of the compressed gears for this style of launch. 0-100 acceleration may or may not suffer because of it, but 0-60 will see good improvements from this method. Again, this is only for extreme cases of horsepower or lack of weight on the drive tires, such as the TVR Speed 12 and the McLaren F1.
I personally use short-shift on many cars, just because a lot of them have weird/bad powerbands and horrible ratios for 5 speed transmissions. In route X it helps a lot for acceleration on launch; online launch improvements are still noticeable but since it's full-throttle launch, your reaction time on the short-shift will determine how much it helps.
Ballast
Ballast is adding weight to your vehicle in order to reduce wheelspin - improving tire grip. You may be asking why I'm talking about something that has nothing to do with the transmission but, please, continue reading. Many cars do not require it, which is why its not always a common tuning adjustment, but it can be very helpful. When in the ballast menu, pay attention to the weight distribution of the vehicle in relation to its drivetrain. You always want to place the weight over the drive tires in order to achieve better grip.
Lets take FWD for example. A 400hp FWD car, such as a Honda Civic or Integra, will have more weight in the front because the motor is there. That motor weight may not be enough to keep the wheels from spinning, if the weight distribution is 50 or less in the front. A healthy distribution for FWD cars is 60/40 or 65/35, anything more is great but don't put excess weight if not needed. If you find a car with a good weight setup from the get-go, you may not need to add any weight at all to achieve maximum acceleration. There are exceptions to this, but not very many.
Now for RWD/MR. Mid-engine RWD have the weight of the motor plus chassis over the drive tires, which means they almost never need ballast. The exception is a lightweight car, like the McLaren F1, which has high horsepower and low weight. Front-engine RWD will depend on the weight distribution of the vehicle. If the weight is 55/45 or less in the rear, you may want to consider adding ballast over the rear tires. Some cars don't like the extra weight, especially if they're heavy already, so you will have to use trial and error to find out for sure.
4WD will almost never require ballast, and I don't know any examples that do, but you can try if it's a last resort to cut off a few thousanths from your time.
Ballast Relation to Transmission
Ballast affects the transmission by putting extra strain on the gears, and the vehicle, and will usually make it bog. It will also marginally reduce the RPM in which you will cross the finishline, depending on the amount of weight added. This is where you reduce the gearing in your transmission for a better launching gear and still reach peak RPM when crossing the 400m mark, instead of being 500 RPMs below it in your last transmission setup.
You can do this by reducing the final ratio before you flip the transmission, lowering top speed but also raising the ratios in the transmission without affecting the gear pattern - therefore not causing shift lag. Whichever way you do it, you will usually want to adjust the transmission after adding/removing ballast, so its best to figure out what amount works best before pouring hours into the transmission just to rip it apart.
