Gearing tuning

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Hi all I know it’s all trial and error with gears on this game. But is there some way to find out what’s best for each car just seems at the moment when I tune gears then test against someone they seem to be alot quicker. I don’t use the ready made calculator because they just give you a standard gear tune.

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Gear tuning isn’t always the issue unless you’re doing a drag race-style testing. Acceleration out of the corner is primarily based driving technique and car build. It’s difficult to match inputs with others.

Knowledge of the motor and aspiration helps. Easy example are v8s in American muscle prefer longer gears whereas 4 cylinder fwd cars prefer shorter gears. You would almost never use a 6 speed in a muscle car because it neuters acceleration but would use a 6 speed in a 4 cylinder since these cars are at peak acceleration near the red line.

Basically no there isn’t an easy way.

It’s worth noting for many classes, tuning of gears isn’t necessary since the PI hit for race transmission can be steep.

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A proven method is just to adjust final drive based on hp:

For cars with standard Forza 6-speed race gear box (2.89, 1.99, 1.49, 1.19, 0.94, 0.78):

Subtract cars power from 400hp, divide by 600 and add it to 4.25:

Example: 325hp
400hp-325hp=75hp
75hp/600=0.125
4.25+0.125=4.375 → Final Drive: 4.38

For cars with custom race gear box:

Subtract cars power from cars stock power, divide by 600 and add it to stock final drive:

Example: 325hp, stock power 300hp, stock final drive 3.30
300hp-325hp=-25hp
-25hp/600=-0.04166667
3.30-0.04166667=3.25833333 → Final Drive: 3.26

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I’ have been looking for a calc to do this , but I m puzzled as to how it can work; consider two identical cars, both with 400hp engines, apart form sole difference that one has redline at 8000, and the other at 7000, due to different torque curves / # of cylinders. They should both be able to hit exact same top speed. Surely they would need a different FD ratio to both hit redline in 6th at same top speed , yet the calc would come up with 4.25 for both… what am I missing?

EDIT: same problem with two completely identical cars where one has 17 inch wheels and the other 18

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Do me a favor and try it out.

Reasoning that it works is that Forza needs to calculate exact PI impact for adding sport or race gear box to a car for each and every engine configuration. That’s why I think they’re running a simplified model that is based solely on hp. Power curves, redline etc don’t matter much.

It’s the method QuickTune uses and I have yet to see a case where it didn’t work. Only exception might be high-speed tracks like Le Mans where you would maybe tweak fd towards max speed.

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One correction to my comments above: I’ve discovered that some cars with low redline and large wheels ( ie Viper) can drive the FD ratio down into the high 2’s. Good news is it still works great.

I also found that a quick way of figuring out how the top speeds in each gear will work out is to just multiply the top speed (from the tuning window, aero at minimum) as follows:

  1. Top speed is shown as 190, but what will the redline speed be in first? Answer = 190 * 0.94 / 3.00 = 60.

  2. What about 5th gear? 190 * 0.94 / 1.05 = 170.

A benefit of tuning the gears in this way for min aero / max speed in 6th is that you will then only need 6th gear on a handful of high speed min-aero tracks; in most cases, 5 will give you all you need.

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Sorry if this is dumb question, but what if HP is higher than 400? Example, trying to tune Volvo STCC with 414HP, for a racing series. Thanks

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Hey fifty how’s it going!? Thought I’d have a look at this because I’ve been struggling getting my gears down on the #56 Z4. Racing in a DOR community league. No change to HP, so if I understand this right on your equation. There would be no change to my final drive, is that right?

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As swerve pointed out, the first question should be whether or not a Race/Sport Tranny is required at all. We have many drivers (over 40 weekly) have participated in over 60 Hot Lap Challenges, and, I have many friends that race online…I know that over 95% of cars do not have either upgrade. Yet, if you need it, then, the easiest is to adjust the FD as fifty suggested. The next step, if you run drag and/or circuit that might require specific gearing then there have been several threads on this topic on the FM5 and FM6 Tuners Garage area. I’d suggest a quick search through those two sections.

PRKid
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I had a look round and it’s helped a lot thank you all

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For track racing i try to find a setting where i have a good gear for each turn, mostly a sports gearbox fits for that, sometimes stock is ok in very rare cases i need a race gearbox (mostly cars that come with racegearbox as stock)

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Same logic, use 414 instead of 325 as in my example.

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Correct.

If you want the optimal gearing for a specific track you might need to adjust individual gears +/- 0.1 or 0.2 depending on track.

Usually though for normal full size race tracks you don’t need to adjust individual gears, just final drive.

And btw QuickTune 7 does all the math for you :wink:

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Cheers buddy

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If you just want to tune the final drive ratio this is what I do.

  1. Divide weight of car by the horsepower

  2. Get the default setting of the 1st gear and subtract it by default setting of the last gear.

  3. Multiply steps 1 and 2 together. Then divide by 100

  4. Add result of 3 to default setting of final drive ratio.

For an example: the Lexus IS-F I tuned today. ( in Forza 6)

Weight: 2,952 - divided by- horsepower: 481 = 6.14

Default 1st gear: 4.60 - subtracted by - default 7th gear: 0.69 = 3.91

first step: 6.14 - multiplied by - second step: 3.91 = 24 / 24 divided by 100 = 0.24

Result of step 3: 0.24 - added by - default final drive ratio: 3.13 = 3.37

You can also use this to tune the rest of your gears as well, just have to use that specific gear’s default setting with step 2.

Here’s a link to where I got this from …