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@Bread, there is probably mathematical way to calculate best gearing according available horsepower and torque, I don't have it
"Stealing" base gears from real life car with approx same engine power and it's easy to start modifying it, there is several gear calculators on net (excel sheets) what you can use when targeting rpm drops to stay on best torque/hp range.
Drag racing circles have good information of that, also excel sheets what can give few tips on journey to perfect gear setup.

I said few years ago this, still same thought is valid.

Longer Final: good for long straight, bad for cornering(understeers), reasonable for car with a lots of torq, hard to recover if skidding on cornering and starts oversteer. Slightly slow on acceleration if too long or not sufficient amount of torq availabe.

Shorter Final: bad on long straight, good for cornering(if too short starts oversteer too easily), reasonable for car with low torq, easy to recover on skidding situations. Quick acceleration if enough grip.

Longest/shortest finals, bad for almost all situations

Finding balance for cornering and straights is a key for our quest, but final gear is not only solution, finetuning gears and making different LSD for different transmission(inc.final) is important.
This comment is valid for normal race track racing, not for drag, on drag you can calculate and test one "Best" setup.


@Jouni, I have few things on mind when doing gearbox to be good everywhere,
1st gear short enough to leave grid on edge of grip, means skidding if throttle is smashed down at once.
2nd gear to suit hairpins, entry to exit
3rd gear long enough to go semi quick chicane, and short enough to be capable powersliding during those if traction is lost.
4th really quick turns/chicane and good pull when gathering speed.
5th straight gear, or really close, one starting gear when tuning starts, final gear gets first base value from this gear, engine have to have power to pull this gear till limiter easily.
6th gear optimised for maximum speed.

If car has only 5 speed box then I'll sacrifice 1st gear to close usage as it is in 2nd with 6 speed box.all dropping one down and fourth gear is close to straight.
Exceptions are really low power/torque and really high power/torque cars, ideology still same.

And yes this means playing with final gear to get desired gear ranges first to exist.

I thought that gearbox is one of the easiest part, but I'm probably wrong.

Ok, I understand how to setup each gears, but how to use that speed and final gear part? Tranny trick was so easy way, very simple to use variables speed and final gear. And it does it's job in the start.

I hope Ode and Bread or someone could tell more about it. Maybe You could fine tune gearbox to this 86 / Brz, just to see how it should be done.

Edit. I use pretty much same technique that Ode and Bread, when adjusting each individual gear ratios. Problem for me is how to use speed among final gear ratio.

Jouni

@Jouni, setting final gear to any value and after that moving speed slider will activate different gear ratio ranges on gears, ie. sometimes you need to set final gear to 3.000 to get good gear ranges exist, after setting individual gears on desired values you just change final gear to desired value ie. 4.111, after final gear last setup you cannot touch speed slider or it shuffles your gears to currently activated final gear ranges.

So final gear is the last change? First gear values and then final gear, I have always done final gear first ( top speed ).

My gearbox at the moment, if there is something changes what is good to do, just let me know
1 4.584
2 3.495
3 2.557
4 2.046
5 1.674
6 1.380
Final gear 3.015

Jouni

You might have to set it first and then move speed slider to get needed gear ratios to exist on gears, when all gears are set then choosing desired final gear.
If needed gear ratios are already there you don't need to hustle with it, just setting gears and then final.

Crazy long final, but makes really short/small rpm drops, probably hard to turn in/drive thru tight turns.
After looking again, not even small drops, just screaming gearbox.

Yes, it's different than standard gearbox. I changed driving style: with standard gearbox I'm on the throttle before apex and this gearbox after apex. With this gearbox I let the car flow to the apex - I like to drive little bit different, but with this gearbox it's impossible. Biggest differences are in turn1, 3 and last turn ( big willow ). I haven't made any changes to setup.

Gearbox is not optimal, but it's fast.

Edit:
Final gear 3.055 is close to very good ( almost rev limiter before turn 3 and almost rev limiter before turn 5 ). There is one bad negative side: it's very easy to loose control in turn 3 and 4 - car is giving little too much power or there are some other reasons. Now my final gear is 3.040.

Jouni

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Just for fun and killing time ( waiting Sinister / Internet connection) I bought a very fast car, Lotus Evora. It's a fastest car I have seen on Big Willow ( 450 pp, over 1.125 kg, tyres rh ).

I have faced some difficulties and that's why I ask some advice for Ode, Bread or someone else.

It's MR car and the problem is the rear end - the car spins easily specially with worn tyres. I have rear arb already in position 1, suspension is pretty soft, I have tried different values of toe, camber and lsd, but I haven't found any good solution. I use ballast 54 kg in position -50 and I don't want to add more ballast

There is also one intresting dilemma in ride high: if I use same ride high in front and rear, the rear end travels lower with soft suspension on the rear ( checked from data logger ). This is not ok. If I stiffen rear end suspension the behaviour of the car change worse. If I rise rear ride high - same result. There must be some other way to solve this, but I don't know the solution.

The main question is, what are You doing different with MR car versus FR ( for ex 86 ) car to get good result?
The answer is intresting because I have faced the same problem with other MR cars for ex probably the fastest car in Big Willow - the little Suzuki.

Jouni

@Jouni, good LSD is enough to settle rear, then suspension changes to manipulate car behavior if needed.
Throw from hat, try one-way lock with medium/high preload. 11-20/31-12/5, means 11/31/5 to 20/12/5. These would be my first tryouts with it, medium 2-way lock could be also on my tests.. I'm not fan of lotus, except re-branded Opel Omega.