Suspension geometry

[Jed-S]

I'm after some recommendations on suspension geometry settings for the S3 to save me a lot of trial and error.

I've got some specs at home but these talk of rear camber of around -1 deg (IIRC) yet my S3 has approx -3 deg of camber so is way out from the alleged factory spec.
This makes me wonder how true these specs are especially considering that the rear suspension was modified several times during the life of the S.

So has anyone come up with some settings for the S that work well?

Jed

[Barkychoc]

Some recent bits here

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[Jed-S]

Barkychoc said:

Some recent bits here

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

I'd seen that but there were no target figures - just his existing ones. It was his camber settings that made me realise how much camber is on my S3.

[Barkychoc]

I haven't a clue really Jed, but are your trailing arms, bushes & wheel bearings all tip top before you start tearing into it?
My trailing arm bushes looked spot on fitted to the car (well one didn't), but when I dismantled the trailing arms all four were shot.

Any tiredness in the rubber bushes I guess would alter the angle slightly.

Chris

[Le TVR]

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Getting the ride heights correct is just as important as the geometry.

[Barkychoc]

Le TVR said:

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Getting the ride heights correct is just as important as the geometry.

Good point - and if you have adjustable shocks it wouldn't take much variation between height side to side to give a spurious camber reading.
Similarly if you have a saggy shock or shock mounting rubber the same applies I guess.

[CTE]

Jed,

If you do not mind forking out a few hundred quid, there is a guy over at Daventry called Steve Guigliami (I think thats how its spelt, from Scarred Stiff racing), and he seems to be able to work wonders. My S1 does not have adjustable toe in on the rear trailing arms, but he set up the front for me, and transformed it. With hindsight, all he did was adjust the tracking, everyting else was about right, but he did check. It cost me £90-00, which is an awful lot to set the tracking, but then I had messed around for weeks, and not got it right, and how many garages etc would you have to visit before it was right? As he says, he has put hours into getting the set up right, so thats what you are actually paying for.

[Jed-S]

Having read the link from Le TVR I had a play this morning and set the front toe in to 20 minutes which seems to provide a more stable feel. It was previously at 10 minutes toe out but the steering was too lively on the back roads plus it tended to followed the camber of the road.
Some more experimenting will follow over the next few weeks.

[Bonefish]

These are the figures I've used, not much you can do to the rear but luckily mine has always been within tolerance here.

Front suspension / wheel alignment
Toe-in (-) / Toe-out (+) mm [º] [-0.50 º +- 0.25 º]
Camber -1 º +- 0.25 º
Rear suspension / wheel alignment
Toe-in (-) / Toe-out (+) mm [º] [-0.25 º +- 0.25 º]
Camber -1.25 º +- 0.25 º

I've got a camber gauge, and tracking goemetry kit which makes it relatively simple to set up. You can get the tracking pretty much there with the length of string going round all 4 outer corners of the tyres, shows up which are toeing in or out.

[Ab Shocks]

If the rear is miles out of tolerance from about 2mm of toe in overall, David Gerald do have shims but if in tolerance, treating the rear as fixed and having 0.75 to 1.00 neg camber and 1mm of toe overall on the front with minimal thrust to the rear will work fine