Suspension Geometry

[Frenchy]

This place being the font of all knowledge someone will surely help me out,has anyone got the details or a linky for the suspension settings for my 88 Turbo S M030.
Getting a full set up shortly after fittting new 968 castor bushes,I am looking for front and rear settings.
Cheers In Advance Peeps ! []

 

[Neil Haughey]

If you want standard settings then ISTR Fen has looked at them all before and the 89 or 90 settings are about the most sporty of the stock settings.

For non stock there are many different opinions and advice but the settings I have aimed for myself and love, go something like this;

Front: 0 toe in, as much caster as you can get from the adjuster, between 1.5 and 2.5 degrees -ve camber depending on tyres and usage.
Rear: 10 minutes toe in and between 1.0 and 1.5 degrees -ve camber. Personally I don't believe you need a lot of camber on the back of these cars. I have seen cars with massive rear camber but have never heard of anyone having problems with the car wearing the outside of the rear tyres to much.

I believe there are many many ppl out there that will back up these settings.

Ride height balance is a bit variable in terms of opinions but I prefer to keep the car fairly flat and IMHO this is what Porsche intended with these cars. Some ppl run the front a little lower and some the rear a little lower but this is easier to mess about with when you have the liberty of being able to fiddle with spring rates and damper settings to compensate.

 

[Fen]

Neil is right that '89 settings are the most aggressive of the Porsche recommended ones - '89 being the year all 944Ts had M030 so it's applicable to the '88 S cars. It may even be the same for the '88 S models anyway.

I found this by looking through the little books officially trained technicians have at my indie's. It is probably also in the PDF workshop manual, though the book I looked at was a different publication. I have it recorded somewhere, but it is with the car's documentation which is with the car rather than me.

 

[333pg333]

I'm not sure of the stock settings but the cars were setup for gentle understeer. I don't think that there was a lot of caster or neg in the stock setup, but neither can hurt. I just had my car on the hoist for a full on session and the guy set it up for track with -4.5 front and 2mm toe out, -3 rear and a smidge of toe in. Now I'm driving around on this until the next trackday and I thought it was going to be like an insane ferral cat, but it's surprisingly fine. Having said that it is on small wheels & tyres 235/40x17 and 255/35x17. If you have an R spec type of tyre I am sure that this would be very ducky-divey by comparison. It also depends on how much understeer you want to tune out of your car. In general on the road, the factory setup suited the average owner, but personally I find the push understeer or lack of turn in a bit annoying. Each to their own.

 

[Frenchy]

Cheers Chaps, I knew you woulld come up with the goods, i am intending using the car road only........I know if i hit the track the bug will bite !
So i will be going with Neil and Fem's recomendations'
Cheers People []

 

[Neil Haughey]

ORIGINAL: Frenchy

Cheers Chaps, I knew you woulld come up with the goods, i am intending using the car road only........I know if i hit the track the bug will bite !
So i will be going with Neil and Fem's recomendations'
Cheers People   []

For road only I would use the sporty end of the stock settings. The -ve camber on the front can have a -ve effect on how nice the car is during extremes of grip. Basically the problem is -ve camber on the front allows you to wind on more steering lock in tight corners and push harder without the front end understeering, this is a problem if you lift of the throttle the front end then bites in hard and causes the back end to snap out pretty quickly. The stock settings with very little -ve camber make for safer handling as they promote gentle understeer. IMHE the tipping point is around 1 degree -ve camber, less then this seems to promote gentle understeer.

The front toe for me is set to 0 as I tried various toe in and toe out settings and decided in the end that 0 toe gives very neutral handling and tends to result in pretty stable handling on bumpy roads i.e. the car doesn't dart around.