Setup advice: Losing the back end
I have to admit I'm addicted to racing the FOX. I just love it. However, I have neither the time nor the in-depth knowledge to fine-tune the setups for each track and optimise my lap times. I just know that most of my spins are caused by me losing the back end by putting too much power down too early on the exit of a corner. However, I feel I really ought to be able to drive this way without losing the back end all the time, rather than nursing the car out of each bend and only accelerating once pinted back down the straight.
Does anyone have some realively simple setup advice about how I could improve on this problem, without me having to spend the weekend reading through 10 pages of detailed information?

Quote from al heeley :

Setup advice: Losing the back end

Does anyone have some realively simple setup advice about how I could improve on this problem, without me having to spend the weekend reading through 10 pages of detailed information?

Well, reading through 10 pages shouldn't take longer than 30 minutes...

I can give a small advice, though I am quite inexperienced with setups:

You could make the rear tyres softer (either pressure or compound, or both)
You could soften up the rear suspension and/or stabs a little.
You could increase the downforce of your rear wing by setting a steeper angle.

You could also reduce the power side locking of the diff. I don't know what you're using but I never need more than 20% with the FOX. More than that will just increase throttle induced oversteer. And given the choice I'd rather spin the inside wheel rather than the whole car anyway, so better a bit too low than a bit too high.

Quote from ColeusRattus :

You could increase the downforce of your rear wing by setting a steeper angle.

Don't really want to do this as we're talking low speeds and downforce from rear wing is not going to be a major factor - will just penalise straight line speed later. Don't think this is suspension-related either.

Bob: Your advice on the power-side diff sounds promising, will try that this evening. Cheers!

How much effect would the diff power setting have on lap times? There are a few tracks, mainly in the fox, where I am within 0.5 seconds or less of the world record. These setups often use high power settings, of 65%, and occasionally I do lose the back end. If I took the easy option, and lowered it to, say, 20% would I notice adverse effects?

Lower corner exit speeds, more/less understeer on power, lower top speed on straights (less acceleration)?...

I would be most adverse to changing the under/oversteer balance on the power too much, because these setups work especially well in the high speed corners - which we all know are the most important corners of a track.

you also should be very careful when you use the exit curbs ... most of the time when i lose the rear in one of the formulas is when i clip a wheel on a steep exit curb and the whole geometry of the car changes drastically
might also be related to the colission detection bugs that sometimes happen on steep curbs the most well known example for that would be the inside of the last curb in the bl1 chicane

Quote from tristancliffe :

How much effect would the diff power setting have on lap times?

Me running a clean lap = 1.22.50
Me losing the back end on a lap = 1.35.20

Quite a difference it makes to me! (Sorry, I sounded like Yoda back there then)

Quote from al heeley :

Does anyone have some realively simple setup advice about how I could improve on this problem, without me having to spend the weekend reading through 10 pages of detailed information?

Have you looked at the forces view, while showing the tyre status overlay in a replay to see what's happening? It's very possible that the inner wheel is getting completely unloaded or the contact patch of the outer wheel is not wide enough (or both).

Things you might also want to try include reducing tyre pressure, increasing rear toe-in, coming out with lower rpm (higher gear perhaps?) so it transfers less torque at that point but can still accelerate without losing the rear.

I found the later to be my problem in Kyoto GP Long's slower turns, I'd go all the way down to 2nd judging by engine sound but had a very slight margin of control over the rear in the exit, once I tried those turns again with 3rd on the same setup and although it didn't exactly "sound right" (motor on edge) it kept the rear in line and accelerated just fine (faster than with 2nd actually because I didn't have to fight oversteer).

Quote from al heeley :

Me running a clean lap = 1.22.50
Me losing the back end on a lap = 1.35.20

Quite a difference it makes to me! (Sorry, I sounded like Yoda back there then)

Lol! Not quite what I meant. I was kind of assuming that in both cases I take a lap in which I didn't spin

Quote from tristancliffe :

I was kind of assuming that in both cases I take a lap in which I didn't spin

In my case, thats a dangerous assumption to make!

Quote from xaotik :

I'd go all the way down to 2nd judging by engine sound but had a very slight margin of control over the rear in the exit, once I tried those turns again with 3rd on the same setup and although it didn't exactly "sound right" (motor on edge) it kept the rear in line and accelerated just fine (faster than with 2nd actually because I didn't have to fight oversteer).

Thats interesting info, sounds again like its related to torque and power transfer, it certainly helps round south city tracks to keep it in a higher gear.
Thx for the input!

Actually I'd try to make the rear tyres a bit stiffer than the front ones. Bob explained somewhere how softer rears induce oversteer, but I'm too lazy to search that now

Generally you can:
- soften the rear AR bars
- soften the rear suspension
- make rear tyres a bit stiffer than the fronts. emphasis is on "a bit"

Maybe using a flatter angle on the rear camber would help too. Why? If you setup your rear camber so the tyre is exactly perpendicular at the highest g load, then you do have the most grip there, but actually less grip at the "accellerate out of corner" phase. But that's pure theory, and I'm no expert, but trying won't hurt (in RL™ atleast).

Quote from tristancliffe :

How much effect would the diff power setting have on lap times? There are a few tracks, mainly in the fox, where I am within 0.5 seconds or less of the world record. These setups often use high power settings, of 65%, and occasionally I do lose the back end. If I took the easy option, and lowered it to, say, 20% would I notice adverse effects?

A more locked diff on the power side will be quicker because you can put more power down. That's why LSDs are used over open diffs in the first place. However in car like the FOX, where grip is high and torque is low, it won't make that much difference since you only really need enough locking to prevent inner wheelspin. The higher the "torque-to-grip ratio" the more power locking you will need.

Quote from tristancliffe :

Lower corner exit speeds, more/less understeer on power, lower top speed on straights (less acceleration)?...

An over-locked diff (i.e. more than what it takes to prevent inner wheelspin) will increase power oversteer in RWD cars. An under-locked diff will reduce it. Top speed will not be affected, but acceleration will be if the diff is so open you can't put down any power.

Quote from tristancliffe :

I would be most adverse to changing the under/oversteer balance on the power too much, because these setups work especially well in the high speed corners - which we all know are the most important corners of a track.

High speed balance in the FOX is largely down to wing settings. The faster you go the less important everything else becomes.

Quote from AndroidXP :

Actually I'd try to make the rear tyres a bit stiffer than the front ones. Bob explained somewhere how softer rears induce oversteer, but I'm too lazy to search that now

Basically the outcome of that thread is that while lowering the tyre pressure increases grip, so doing this to the rear tyres would help reduce oversteer, it also increases the optimum slip angle, which would increase oversteer. So basically, changing the tyre pressure at one end of the car can have a seemingly random affect.