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This is the unofficial transmission guide for tuning your custom transmission in Gran Turismo 6, for drag racing. You can gain access to this by purchasing custom transmission in the tuning section of your car.
Right away, you can see it is a Front-Engine, Rear-Wheel Drive car, weighing less than 1200kg & making almost 600 horsepower. It's not a heavyweight contender, but it holds its own against cars in that horsepower range. Being FR, although not shown in the pictures, makes it front heavy and prone to lots of wheelspin. Also notice it makes peak power within 800 RPM of its maximum RPM, meaning it will want to rev high during your run at the strip. This sets us up with a big issue.
It's hard to see why its so bad, at first, since it almost looks like an ordinary transmission or even a stock transmission for some of the cars in this game. Lets compare it to the power graph as a on-side by side comparison:
Using the power graph of the car in the tuning sheet, you get a realistic look at what the power output is for each gear, and where the power starts & stops. Once again, it doesn't really seem too bad, right? How about we see how big the gaps are in gears when we compare shiftpoints:
With the first three gears having huge gaps between them, it will be causing issues with any sort of launch you attempt. By the time you get to 3rd gear, the other guy will already be 1 or 2 cars ahead of you. Fourth and Fifth don't seem horrendous, but there is significant spacing between them meaning you will be using them for a good bit of time between shifts, possibly meaning the transmission is too stretched for your situation, or it'll seem like you're in that gear a lot longer than you need to be.
Now that you have your transmission "flipped", it's time to tune it properly. I chose this car because I've witnessed a lot of people have issues tuning 5-speeds, both on GT6 as well as back on GT5. As for most RWD cars, 1st gear will usually be far left. 2nd gear, on most 6-speeds & higher will want to stay where it is as stock. This being a 5-speed, you have to compensate for more gear-spacing and therefore moving 2nd roughly .040-.075 right of starting position. 3rd gear will also be further right than a 6-speed setup, around 3/4 of the way to the right. 4th and 5th will be far right, as would be any further gears assuming you'd have them. This demonstrates the correct method:
If you did this correctly, the graph gear chart should appear something like this:
Now you're probably scrolling above to look at the differences from this and the "bad" setup. To the untrained eye, there doesn't seem to be a significant change. Why don't we compare it the same as we did before:
Each gear has enough space to compensate for the powerband and more, meaning the car won't be struggling for power between shifts and you won't have to over-rev out of the powerband so the next gear won't bog. This final comparison will show the shiftpoints & powerband:
In this setup, the gearing is as tight as possible while still having excellent power-spread and minimized hesitation/bogging. It may not be common knowledge, but 5-speeds are notorious to have atleast some bog between 1st & 2nd, just because its the largest gap in the gearing & makes up for spacing compared to a 6-speed. If you can short-shift to 2nd in any situation while using a 5-speed, do so and it will ensure that you have the best possible scenario for your transmission to succeed in the race.
You'll also notice that the powerband makes peak power at 7600 RPM, 2000 under its maximum RPM as well as losing power steeply after peak. This means we won't be able to rev much past 8000 or 8200 during shifting or else we will be outside of the powerband. We also want to make sure the RPMs stay below 8500 when finishing the race, or else we'll lose pull and the opponent will pass.
For AWD cars, especially low-powered ones, transmission flip isn't as easy as a RWD car. It requires knowledge of how fast the car will be trapping at the shadow at Indy as well as how it reacts to gear changes and how much it bogs from launch. The best method I've found for low horsepower AWD cars is to use a low flip, such as .500 above minimum final gear, then move to lowest top speed, and reduce the final gear to its lowest. After this is done, for this specific car we will use this ratio gearset:
You'll notice this car also has a 5-speed transmission, which was especially hard to tune being an AWD powertrain. Using these ratios we will get this result:
Then, using the method used before, we will compare to the powerband:
It may seem like a bad fit at first, but this much of a stretch of the last 2 gears is necessary to promote enough top-end to cross the line at Indy without exceeding the threshold of powerloss after 8500 RPM. The first 3 gears are shrunk, or moved right, to compensate for bogging created by the low horsepower of the car.
In order to use this transmission, you'll need to rev the car to 8500 before each shift, so that the power will never drop less than 50 horsepower below peak. The exception to gear stretch in this case, is never to stretch your last gear more than halfway to the left, as it will cause extreme gear lag and drop you into low RPMs. If you find yourself in need to do this, then you have to choose a higher ratio before you flip the transmission.
Some people might tell you to lower your rear ride height to reduce bog for AWD cars, and it does help, but it also hurts you at the same time. Lowering rear height will reduce traction on launch and impedes acceleration. Using that method instead of adjusting gears, will give a mediocre takeoff and slowly fall behind the other car who is using proper suspension & gearing.
Alternative AWD SetupAs for the higher horsepower'd Subaru & Mitsubishi counterparts, these ratios are better suited for their peaky, near-redline powercharts:
It will get a quicker & harder launch than an all-left stretch on first, and a closer 2nd gear will keep the low-speed acceleration as fast as possible, as soon as you go from 3rd to 4th, the back-end stretch begins and these gears are only stretched enough to keep you in the powerband or prevent hitting the rev-limiter before the finish. These would be set up between .600-.750 above the lowest final ratio and, as horsepower increases, then so does the flip ratio.
Front wheel drive vehicles are quite a bit different than rear-wheel drive. For starters, they spin their drive wheels significantly more. They also like closer ratios, run much lower speeds in the 1/4 mile, and most prefer lots of ballast to launch to prevent melting your tires. Here is my example for FWD, the Pontiac Sunfire:
The Sunfire makes peak power close to redline, and power slowly drops off after, so you can shift slightly after peak without major power loss. One thing that separates this FWD from others is that it is one of the few with a supercharger. Most FWD with superchargers have a better launch than turbo-inducted FWD, but I still suggest 100 ballast at -50. Because FWD have a low speed at the shadow, they prefer lower flips than most RWD. I would suggest .500-.650 above minimum final ratio as a base flip, then adjust from there. Here is the example of where a good setup would place the ratios and what the chart will look like.
When you compare where the Sunfire makes max horsepower on the graph, and compare it to the gear chart, you get this:
When looking at the shift points, peak horsepower, and maximum overall horsepower of the powerband, you'll see this transmission never falls below 50 horsepower from peak. This is one of the best setups you can hope to achieve on a FWD car. As said before, ballast plays a crucial role in 95% of FWD cars, so you will want to adjust it with each transmission flip to see if you're getting maximum acceleration.
(Lowest Top Speed of Car/Lowest Final Ratio) x Final Ratio Transmission was flipped at = GT5 Top Speed
Camaro as example: 112 divided by 2.5 = 44.8 x 3.5(flipped ratio) = 156. Subtract 15-20mph, as per GT5 logic for top speed, and you have your established top speed when flipped. I ran 141-142 mph using that flip at SSRX. If anyone finds a flaw in this method, please let me know and I'll modify or remove it.
Powerband
Rear Wheel Drive(RWD)
Before you start tuning the new and improved drag machines of GT6, you will have to take a moment to understand your car and its layout. Many cars of the GT5 drag scene now have increased horsepower, reduced weight, or both. This means you cannot simply copy & paste your tunes from the old game here and expect it to work. It might be a helpful start, or it could be a disaster. This is when you have to evaluate your cars' attributes. In this guide, I'll be using the 1969 Chevrolet Camaro Z28 as an example, and possibly other cars will be added in the future:Rear Wheel Drive(RWD)
What is Bog? Why is it Bad?
Bog happens when your gears are separated too far apart, causing the car to decelerate in RPM. This is not what you want to happen, as it will slow you down. This is not to be confused when, during launch, your RPMs drop a couple hundred to compensate for traction - this is a good thing; bog is when your RPMs drop several thousand and/or to the point where your car loses almost all acceleration. Here's an example of a transmission that's been overstretched to compensate for lost traction during wheelspin:
Transmission Flip & Proper Setups
I've discussed transmission flip in the previous guide, as well as numerous other threads talking about methods. Basically, it is taking the tight gear-spacing of the lowest top-speed your car has, and stretching it out just enough to make use of a good launch & top speed for the drag. The easiest way to do this, is to first reset your transmission by selecting stock transmission, then back to custom. After doing this, select your final ratio in which you want to affix your new gearing(how much you want to stretch). The higher your ratio, the more it will stretch the gears. After you select the ratio, move your top speed slider as far left as it will go. Then proceed to move your final ratio the same way you moved your top speed - as left as you can.
Now that you have your transmission "flipped", it's time to tune it properly. I chose this car because I've witnessed a lot of people have issues tuning 5-speeds, both on GT6 as well as back on GT5. As for most RWD cars, 1st gear will usually be far left. 2nd gear, on most 6-speeds & higher will want to stay where it is as stock. This being a 5-speed, you have to compensate for more gear-spacing and therefore moving 2nd roughly .040-.075 right of starting position. 3rd gear will also be further right than a 6-speed setup, around 3/4 of the way to the right. 4th and 5th will be far right, as would be any further gears assuming you'd have them. This demonstrates the correct method:
All Wheel Drive(AWD)
Now I'll be discussing tuning methods for All-Wheel Drive vehicles, such as this Ford RS200. It weighs slightly under 1100kg, and has 484 horsepower. Its weight distribution is quite even, having a bit more in the back than the front. Because of this, the car will want to grip more on the rear wheels, and have a tendency to bog under high gearing. This means we will need to use special gearing for this vehicle, especially because of the low horsepower.
Flipping for All-Wheel Drive Transmission
For AWD cars, especially low-powered ones, transmission flip isn't as easy as a RWD car. It requires knowledge of how fast the car will be trapping at the shadow at Indy as well as how it reacts to gear changes and how much it bogs from launch. The best method I've found for low horsepower AWD cars is to use a low flip, such as .500 above minimum final gear, then move to lowest top speed, and reduce the final gear to its lowest. After this is done, for this specific car we will use this ratio gearset:
You'll notice this car also has a 5-speed transmission, which was especially hard to tune being an AWD powertrain. Using these ratios we will get this result:
Then, using the method used before, we will compare to the powerband:
In order to use this transmission, you'll need to rev the car to 8500 before each shift, so that the power will never drop less than 50 horsepower below peak. The exception to gear stretch in this case, is never to stretch your last gear more than halfway to the left, as it will cause extreme gear lag and drop you into low RPMs. If you find yourself in need to do this, then you have to choose a higher ratio before you flip the transmission.
Some people might tell you to lower your rear ride height to reduce bog for AWD cars, and it does help, but it also hurts you at the same time. Lowering rear height will reduce traction on launch and impedes acceleration. Using that method instead of adjusting gears, will give a mediocre takeoff and slowly fall behind the other car who is using proper suspension & gearing.
Alternative AWD Setup
It will get a quicker & harder launch than an all-left stretch on first, and a closer 2nd gear will keep the low-speed acceleration as fast as possible, as soon as you go from 3rd to 4th, the back-end stretch begins and these gears are only stretched enough to keep you in the powerband or prevent hitting the rev-limiter before the finish. These would be set up between .600-.750 above the lowest final ratio and, as horsepower increases, then so does the flip ratio.
Front Wheel Drive(FWD)
Front wheel drive vehicles are quite a bit different than rear-wheel drive. For starters, they spin their drive wheels significantly more. They also like closer ratios, run much lower speeds in the 1/4 mile, and most prefer lots of ballast to launch to prevent melting your tires. Here is my example for FWD, the Pontiac Sunfire:
The Sunfire makes peak power close to redline, and power slowly drops off after, so you can shift slightly after peak without major power loss. One thing that separates this FWD from others is that it is one of the few with a supercharger. Most FWD with superchargers have a better launch than turbo-inducted FWD, but I still suggest 100 ballast at -50. Because FWD have a low speed at the shadow, they prefer lower flips than most RWD. I would suggest .500-.650 above minimum final ratio as a base flip, then adjust from there. Here is the example of where a good setup would place the ratios and what the chart will look like.
When you compare where the Sunfire makes max horsepower on the graph, and compare it to the gear chart, you get this:
When looking at the shift points, peak horsepower, and maximum overall horsepower of the powerband, you'll see this transmission never falls below 50 horsepower from peak. This is one of the best setups you can hope to achieve on a FWD car. As said before, ballast plays a crucial role in 95% of FWD cars, so you will want to adjust it with each transmission flip to see if you're getting maximum acceleration.
Top Speed Equation
To everyone that already has prior knowledge to this method of tuning, here is a nice nugget of information to have at your disposal. If you're flipping your transmission using the lowest top speed, use this formula:
(Lowest Top Speed of Car/Lowest Final Ratio) x Final Ratio Transmission was flipped at = GT5 Top Speed
Camaro as example: 112 divided by 2.5 = 44.8 x 3.5(flipped ratio) = 156. Subtract 15-20mph, as per GT5 logic for top speed, and you have your established top speed when flipped. I ran 141-142 mph using that flip at SSRX. If anyone finds a flaw in this method, please let me know and I'll modify or remove it.
Additions/Improvements
This section will be open to all future additions for the guide, and to add anything that has been suggested. If I decide to tune futher cars for examples, they will appear here. I hope this helps clear any issues with people still having trouble - for those of you that are confused or wanting to know more information about something, please post and I'll do my best to help.
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