[Subscribe to Daily Digest] |
Short answer is more toe out, more neg camber, and more pos caster. Stronger rear anti-sway bar would be nice too. You are making alignment changes that will counter the stock setup of understeer and make the car more balanced.
Think about this too: If you are going to do only 1 alignment, then you will have to keep it conservative to save your tires after the track day. If you can do one setup for the track and then set back to stock/sporty for the street, then you can get more aggressive with the track setup. You can see that a knowledgeable technician with an alignment rack that knows you and your Saab can go a long way for performance and enjoyment! Get recommendations from performance parts stores, racing buddies, whatever you can.
You didn't mention if you have rubber or poly front suspension bushings. Rubber moves while driving, so for instance it generates dynamic toe-in on acceleration and toe-out in braking. Poly, delrin, brass, and steel rod ends do not flex/move nearly as much, so they deliver consistent settings from the alignment rack to the track.
For your track day on a stock car, set toe at zero. This will help the car turn-in better, which will help overcome understeer early in the corner. If you have poly bushings, push this setting to 1/8” toe-out.
In the middle of the corner you want steady speed (steady throttle) and maximum g's without understeer. Bring on the negative camber! A good track setting for front street tires is -1.5 degrees, -2.0 if you think you're fast. Race tires can go -3.0 degrees!
Stock settings for caster are usually very mild, and you'd like to get around -2.5 to -3.0 degrees for strong on-center feel and steering wheel-return after a corner. However on the ng900 and 9-3 with mac-strut front suspension, the adjustment simply isn't there. Even if you ovalize the top mounting holes, the strut won't move very far before the spring makes contact with the chassis. I believe your Aero is the same way, so you are stuck with whatever the factory setting is.
How about tire pressures? Consider it like this: lower tire pressure gives a larger contact patch, and a larger contact patch delivers more grip. You are using street tires, so you have a limit on the low side of having the sidewall "rollover" and at that point you have basically zero contact patch. I recommend 42-44psi rear and 38-40 psi front (cold pressures) as a starting point. From there you can adjust on track. For instance if the car still understeers, pump up the rears a few psi(give them a smaller contact patch).
Good luck and have fun! Damien
posted by 65.78.13...
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
