My take on Transmissions

[hoodrich902]

I think that I may have come up with a great way to tune transmissions. Lets say you have a car with 300 max hp at 8k and 250 torque at 6k you need to find what percent of 8k will get you 6k. In this case 75% set your top speed. Then go to the gears lets say this car is 5 speed with the following ratios...

1st. 3.76
2nd 2.33 84% 6720 rpm
3rd 1.61 69% 5520 rpm
4th 1.23 76% 6080 rpm
5th 1.00 81.3% 6504 rpm

So what you would want is a difference of 75% between each gear so that every shift you're at 75% of 6000 rpm

1st 3.106
2nd 2.33 6001 rpm
3rd 1.747 5998 rpm
4th 1.310 5998 rpm
5th 0.982 5996 rpm

As for the final gear ratio set it to whatever you like whatever you feel is comfortable for the track.

Another Example this gen coupe https://www.gtplanet.net/forum/thre...p-updated-18-02-14.291743/page-8#post-9140139
Im going to assume max hp is at 6800 and max torque is at 5400 so what percent of 6800 is 5400? .795

1st 3.300
2nd 2.025 61.3% 4168 rpm
3rd 1.550 76.5% 5202 rpm
4th 1.225 79% 5372 rpm
5th 0.975 79.5% 5406 rpm
6th 0.775 79.4% 5399 rpm​

​

Final 3.600

1st. 2.547
2nd 2.025 79.5% 5406 rpm
3rd 1.610 79.5% 5406 rpm
4th 1.280 79.5% 5406 rpm
5th 1.017 79.4% 5402 rpm
6th 0.809 79.5% 5409 rpm

To get the first gear I took second gear 2.025 * X = .795 and X=2.547 once I had that I just kept multiplying by .795

If these numbers can't be achieved could someone let me know I'm not online at the moment but if someone could test this it would be much appreciated. I want a second opinion on this this is all just a spur the moment hunch because I had to go to work

 

[oppositelock]

This method doesn't work, I've tried it. Not only will you play hell trying to fit the gears into the allowed range, but the RPMs don't actually drop where you'd think they would. The end result is that your lower gears are far too close and your upper gears are too far apart.

 

[REXSPEC]

I have a gear calculator I use to get better gear tuning. It mirrors the GT graph perfectly, however it gives me the exit and entry speed of each gear and the entry rpm, all the way to wherever the top gear lands, no more invisible gears because they are stretched far. With it I can tune the gears to grab at the same rpm when shifting at red line but I found that is not always ideal. It always seems to get better pull if the next gear grabs at a little higher in the rpms then the last, except for overdrive.

 

[Adrenaline]

The actual calculation, for what you are trying to accomplish is as follows: (In game, as well as in real life)
hp(6/5)=tq
Where the 6 and 5, correspond to the individual gear ratios.
Obviously, get your 6th gear and final gear, by knowing your needed top speed.
Then use basic Algebra to solve for X(in this case 5th gear), once you input your 6th gear.

6/5 = tq/hp
5th gear = (tq/hp)6th gear

I haven't used it in GT6 yet, but in GT5 it did work correctly. But as Opposite pointed out, it's hard to get the correct value ranges needed, and fairly often, not even possible.

You don't have to use peak tq and hp numbers, you actually want to find the 'powerband' which is the highest average tq/hp possible within a given range. Doing so, you can accurately define the exact RPM range every gear will go through. But keep in mind, that Max tq to max hp isn't always the optimal 'powerband', despite what some may believe.

Edit:
Did some digging and found this in my GT5 files.
https://docs.google.com/spreadsheet...FiVW40TEp0cW16U2JaVUNPd0E&usp=drive_web#gid=0

This is a spreadsheet I created that has dual function.
The first is that you can input your desired HP (where you shift) and TQ (what rpm you want the next gear to begin at) and it will automatically calculate the gears for the rest of the transmission.

The second side of the spreadsheet, is to help you try and find a value in game that works, by manually selecting your 6th gear, and it will then give you 5th through 1st gears.

Only alter the grey background cells.
*As of right now, the spreadsheet is doing something weird with decimals and commas. But you can still figure it out, I'll see if I can fix it in a few.
** The issue seems to be with GoogleDocs being confused with what is a decimal and a comma.
It thinks commas are decimals and decimals are commas. So when you input a gear use 1,234 instead of 1.234
/shrug

 

[Lambob]

^ Hello and thx Adrena,

to correct your spreadsheet, your cell A4, it is currently a constant value of 9000

I think if you simply change it to be =A2, then all should work as intented

 

[Adrenaline]

^ Hello and thx Adrena,

to correct your spreadsheet, your cell A4, it is currently a constant value of 9000

I think if you simply change it to be =A2, then all should work as intented

Thanks. Fixed that, but there is still an issue with . vs , in the document.