Hi, I have an A3 1.8 -96 that needs to get some road holding upgrades. The goal is to make it good enought to try som autocross or similar. I do not want to lower the car more than ~10mm since it is not allowed where I live without making a special registration which is quiet expensive and also takes a lot of time.
I have calculated what the OEM spring rates are and front is about 16N/mm, rear i would say ~27-30N/mm.
So a few questions:
1. Has anyone done any more advanced calculations on spring rates and dampers on a 8L A3?
2. Does anyone know approximately what the unsprung weight is front/rear?
3. What is the "MR" ratio for the A3 (How much does the spring move when the wheel moves?)
4. What would you recommend as resonance frequency for combined autocross and normal road driving? 1.5Hz?
I have looked in one of the budget car parts stores here in Norway and there are several springs from other cars that could potentially fit the A3. A mercedes spring is available in correct size for the front but with 17mm thread diameter instead. This spring will have 74N/mm spring rate, almost 5 times more. The price is only ~20GBP each.
5. Would you consider 74N/mm to be too agressive for my purpose?
I have also thought a little bit about shock absorbers. There is a UK based company called GAZ who have pretty resonable priced adjustable dampers.
6. Does anyone have experience with GAZ shock absorbers?
7. Does anyone have a damping curve for the standard GAZ shocks as a function of knob-setting?
8. I was also wondering if there are any easy ways to get more agressive wheel angles?