How do I tune the transmission in the right way?

  • Thread starter TT3AZ
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TT3AZ

TT3AZ

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tt3_az
TT3AZ
Hello I have a question regarding the transmission, since we now can tune the gears individualy.

Lets say second gear is stock at 2.470, and i change it to 2.393 because it suits my purpose better. What will i set 1 gear to if it is stock 3.666, and then 3, 4, 5, 6 gear etc. I want the same relation to all gears as stock, but with modified numbers if you understand what i meant, so i get a smoth acceleration all the way up to top speed.

I tried this method:
2.393 is 0.968421052% of 2.470 (stock). Then i multiplicated 0.968421052 with 3.666 to get first gear ratio, and second gear, etc, etc.

This method doesnt seem to work, because the gear ratios max and minimum differs from gear to gear.

Minimum for 1 gear on a certain car when setting the Max Speed is 3.187, and max is 4.353. 4.353-3.187 = 1.66. Second gear from minimum to max is 0.745, third gear max to min 0.435, 4 gear etc.

Do you have any calculations for this issue?

Here are the complete list:

1st Gear - Min 3.187, Max 4.353. Stock 3.666
2nd Gear - Min 2.203, Max 2.948. Stock 2.470
3rd Gear - Min 1.635, Max 2.070. Stock 1.804
4th Gear - Min 1.273, Max 1.550. Stock 1.382
5th Gear - Min 1.140, Max 1.218. Stock 1.110
6th Gear - Min 0.759, Max 1.005. Stock 0.935
Final Gear - Min 2.000, Max 5.000. Stock 3.266
Max Speed: 310 km/h

What I want:

1st Gear - Min 3.187, Max 4.353. Modified ????
2nd Gear - Min 2.203, Max 2.948. Modified 2.393
3rd Gear - Min 1.635, Max 2.070. Modified ????
4th Gear - Min 1.273, Max 1.550. Modified ????
5th Gear - Min 1.140, Max 1.218. Modified ????
6th Gear - Min 0.759, Max 1.005. Modified ????
Final Gear - Min 2.000, Max 5.000. Modified ????
Max Speed: 400 km/h

The car is a Toyota Supra RZ, and im going to use it for drag racing high speed.

tt3_az
 
Adrenaline
You'd just use the differential... (Final Gear)
Click to expand...
Yes I know, but I still need a algorithm so I can set gears individually, the final gear ratio doesnt solve my problem. I dont know im really confused, but i want close geared transmisson, but still i want to be able to reach high top speeds. Because if you are running 1/4 mile you dont want any rpm drops when changing gears, so you top out pretty fast. I want to use this method to accelerate fast to top speed, reducing rpm dróps as much as possible.

I used these random settings, and i didnt lose as much rpm when shifting gears as stock settigs, how ever i want to understand the theory behind this so i can tune my transmission, and actually know that im doing. Do you see anything at all from these numbers?

My settings:

1st Gear - Min 3.187, Max 4.353. Modified 3.555
2nd Gear - Min 2.203, Max 2.948. Modified 2.393
3rd Gear - Min 1.635, Max 2.070. Modified 1.747
4th Gear - Min 1.273, Max 1.550. Modified 1.388
5th Gear - Min 1.140, Max 1.218. Modified 1.075
6th Gear - Min 0.759, Max 1.005. Modified 0.905
Final Gear - Min 2.000, Max 5.000. Modified 2.609
Max Speed: 400 km/h (original 310)
 
TT3AZ
Yes I know, but I still need a algorithm so I can set gears individually, the final gear ratio doesnt solve my problem. I dont know im really confused, but i want close geared transmisson, but still i want to be able to reach high top speeds. Because if you are running 1/4 mile you dont want any rpm drops when changing gears, so you top out pretty fast. I want to use this method to accelerate fast to top speed, reducing rpm dróps as much as possible.
Click to expand...

Best way to get your ratios as close as possible while still being able to have a high top speed is as follows:

Final drive to max (5.000-6.000 depending on car), autoset/top speed to minimum. Make top gear as short as possible, first gear as long as possible. Space other gears evenly. Set final drive so that your top speed is something reasonable.

Result? First gear is extremely long, tight spacing for the rest. This works exceedingly well with higher power FWD and RWD cars; AWD will need a shorter 1st gear to launch properly.
 
Honestly, unless you have a car that needs to have specific gearing changes, like Adrenaline said I'd just use the final gear to adjust top speed. If the specific gear has an excessively long final (overdrive) gear, you can shorten that some. Otherwise, I wouldn't bother messing with it.

Gearing is multiplied, so the effective gear ratio is the (Gear Ratio)*(Final Gear) so changing either the individual gear ratio OR the final drive will have the same net effect. If you want to shorten all gears, shortening the final drive will have the same effect.

Having a close (short) geared transmission means you reduce your top speed, so if you make all your gearing close, and then put a long final gear to increase top speed, it's just like having longer gearing.

You're not going to find an "algorithm" or anything because optimum gearing is specific to powerbands and what the car is being used for.

Let me know if this doesn't make sense.
 
Okey man, I understand now, and what I wanted was a close gear transmission with 1st gear long enough, and the other gears short enough to prevent rps drops, still beeing able to reach high speeds. I Think i have found a way to do this, and my setup is like this, take a look:

1st Gear - 3.241
2nd Gear - 2.330
3rd Gear - 1.824
4th Gear - 1.473
5th Gear - 1.222
6th Gear - 1.037
Final Gear - 2.279
Max Speed: 300 km/h (Actuall top speed 400 km/h)

With this I top out about 75 mph (120 km/h) in 1st gear, and that is good, because I use to launch in 2nd gear and top out about the same speed, but the acceleraton was slower. No it seems that I have okay acceleration from 0 - 364 km/h. The only rpm drop that is critical is from 1st gear to 2nd.
 
Ok, I'm a beginner in the tuning section of the GT series and would like to know how you guys decide on a car X how to tune the gears?

Top Speed: do you start somewhere near the cars possible top speed or isn't the top speed bar that important and only work with the final and 1st-5/6th gears?

Final gear: go low or high than stock settings? I just played around with a car and set it lower than the stock settings after that I looked up a tune and he went completly the other way and set the final gear higher than stock, is there a reason? Why you go one or the other way?

1st: short/low value = makes less wheelspin?
2nd-4/5th: just somewhere in between? 2nd lower to 4/5th higher values?
Last gear: to reach somewhere near top speed?


Or would you suggest me to just work with top speed settings? Or rather only with final to begin with?


Edit: on the car specifics sheet on the tuning menu are the 2 RPM values and what do they mean? I have the german version of the game and it isn't that clear for me. One is xxx kW/8000 RPM and the other is xxx NM/6000 RMP one is peak power and the other peak torque or is that the same?
 
Although this may not be directly helpful, I think it is helpful in tuning transmissions in general. This is track independent information.

Generally speaking, you want a car that puts your power down effectively in lower gears and hits its top speed near maximum rpm (with some room for draft) in its final gear.

An effective way of knowing whether to use a 2.0 or a 4.5 final gear ratio is to look at your HP/TQ power curves. The idea is that when your car changes gear, it lands right back in right below or at the peak power of the engine. Using the slider and testing will allow you to find this happy medium.

The top speed slider allows you to adjust for any given track without having to mess with your ratios. This is very useful once you have tuned your transmission to your liking and don't want to change it for every track.

As complicated as some people will try to make it. The final gear ratio is not all that important (ignoring track). Your best bet is to use every gear and to hit your top speed near the maximum of your final gear. If your car does that, then you are effectively geared correctly.

The minor differences that can occur after this point is tuning your first gear individually to get the best launch and tuning for specific tracks that have lots of very slow corners in which you may want to tune more for your torque band then your power band.

Some helpful notes:
If you are hitting the rev limiter in your final gear, you need to lower your final gear ratio. (Ex. 4.0 to 3.85).
If you are sitting 2000 rpm from redline in your final gear, but you are topped out you need to up your gear ratio. (Ex. 3.85 to 4.0)
If you are burning out in your lower gears, you either need to adjust them lower individually or mess with your final gear ratio. A good way to solve this is to not mess with your final gear ratio, but to instead make your lower gears very long (lower value) and then your top gears very short (higher value). This will result in basically the same results as leaving the ratios stock. But, this will help with traction issues on higher HP cars in low gears. This will not be optimal when compared to your HP/TQ curve. But if you are not getting traction, that is not optimal as well.
 
Last edited:
Rotary Junkie
Best way to get your ratios as close as possible while still being able to have a high top speed is as follows:

Final drive to max (5.000-6.000 depending on car), autoset/top speed to minimum. Make top gear as short as possible, first gear as long as possible. Space other gears evenly. Set final drive so that your top speed is something reasonable.
Click to expand...

I read through this yesterday and tried this example last night on a few cars and I guess I'm missing something. The "autoset/top speed to minimum" portion, I took this as selecting the adjustible "Top Speed" field below the "Final Drive" field to the lowest setting. This moved ALL of the "gear lines" to the left. I then made the "top gear" as short as possible, I'm assuming "top gear" means the last gear, such as 5th or 6th if there is one, and NOT the final gear? I spaced all the gears evenly, then I "set final drive" so that my top speed is something reasonable. By that, does that mean I adjust the Final gear only? And once done, I leave the bottom "Top Speed" adjustable field as is?

Sorry but I'm struggling to grasp the theory of gearing and trying to learn. I seemed to get a pretty fast car ('69 Camaro on Daytona), I could get up to 4th gear but 5th gear wouldn't kick in. I messed with it some more and finally got 5th gear to kick in but wouldn't get anywhere near my redline and would actually slow down slower than I was in 4th gear.

I need to take a GT5 Tranny Tunning Class... :) Thanks for any light anyone can shed.
 
Hey, nice to see that are still people playing GT5, i play because i love drags and i hate that GT6 hasn't a method of recording your quarter mile time
 

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