can someone please inform me what spring rates are generally used on 944 turbos set up for PCA CLUB RACING and/or SUPERCUP Series?

Does everyone run coil springs in rear or do some also run torsion bars in rear?

 

If you're interested in staying in the stock PCA class, you have to retain your torsion bars. Almost everyone also runs coil-over shocks in the rear to stiffen it up. Not sure what the 944Supercup allows.

I'm investigating this myself and have found 2 things:
1) everyone runs different spring rates to suit their driving styles. I've seen everything from 450-1,000 lb front springs being used by fellows (or ladies) running near the front.
2) driver skill and suspension tuning have as much (if not more) influence on lap times than spring rate.

Just my minimally-informed opinion.

Since some people aren't inclined to share information such as spring rates (after all, you are the competition), I'd suggest working with a well-known shop or retailer that sets up a lot of cars. Find one that has set up several in different variations to suit different driving styles and/or tracks so they can tailor a setup to your needs.

Some of the retailers that come to mind are:
Redline Rennsport (John Hajny) (also active Forum participant)
Racer's Edge
Paragon Products
Fast 44s
944 Enhancement (Chris White)
Lindsey Racing

 

Here you go: just upped the rear springs in my SuperCup car from 700# to 750#. Front spring rates are a highly guarded secret. Setup can be an expensive process, so some are not too free with the info.

944SuperCup grandfathers PCA Stock class rules for setup, although you also need to comply with NASA CCR for safety [different cage specs, no coolant, remove steering wheel lock, et al]. Suspension specs are pure PCA, which means free so long as stock setup points are retained. Camber plates must be pinned in stock position, and rear torsion bars must be fitted [although they can be indexed out of play].

 

What a worthless rule .... especially if the scruts know this.

Jase

 

Hey Cooz;

Jerome got you started right. If you're just starting out, stay a little softer. Stiff springs demand some pretty stiff talent at the limit, particularly in the rear. You want something forgiving to hone your skills with.

Speaking of the rear, the t-bars must be "retained" for PCA stock. You need to decide right off whether you want to go the bigger t-bar route, or skip it and do coilovers. You're going to have to drop the t-bars once no matter what, but "eliminating" them means only having to do that ONCE. It requires some expensive setup work either way, but "eliminating" the t-bars makes it much easier from then on to do spring changes and suspension setup.

Most either grind the splines off one end or have them machine turned to an insignificant diameter in one spot. Both methods "retain them" to satisfy the rules, but render them invisible to the setup, and greatly simplify setting ride height and coil spring preload.

I would suggest you go no higher than 450 front to start. That works very well, but is not too demanding. Getting upwards of 600+ requires more ability, especially in the rear. If you reindex and retain your t-bars, a 200lb coil will give you somewhere under the 300lb range rear, which will work well.

That's a start. Getting the idea this is not child's play?

 

Like John said, it's not child's play, and everyone has a different method/philosophy.

I run a wheel rate of about 500# at all 4 wheels. For the rear, I have smaller than stock torsion bars, and coil over helpers -- this gives me more flexability in ride height adjustments.

An excellent handling car I drove had 450# springs in the front and 31 or 32mm hollow torsion bars in the rear. (which yields almost equal wheel rates front and back)

I've talked with people that run 700# springs in the front, and a wheel rate of 300# in the rear -- with the logic that the front end of the car is under more load entering a corner.

Likewise, I know people that have the opposite setup. 400# in the front and twice that in the rear -- to prevent the rear from "squatting down" under acceleration.

I'm not going to tell you which you should do, trial and error with your driving style will be the best test. However, coil overs make it easy to change rates -- not supper easy, but pretty ease. I will recommend that your shocks should be valved correctly to match your spring rates -- either adjustible or adjusted by the manufacturer.

Good luck!
-Van