2nd September 2002, 21:44
Member, P500 Sport, DSC On (>700)
Join Date: Dec 2001
Location: Sunnyvale, CA
E46 M3 IR/IR SMG II
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Well I have done the full suspension kit. I mostly autoX the car but it will see some track track time latter.
There are two parts to the equation. If you are somewhat new to track events then the #1 focus should be on improving the driver. To do that I would leave the car close to stock. Replacing the TA bushings would be a good thing to do even in this case. I have a friend here locally that made the mistake of preping the car to the limit first and then trying to learn to drive it. It doesn't work real well.
A stock M3 has a some issues that limits its ability on the track.
1. The springs are way too soft. With good 'R' tires you can get so much roll you can just about hit the bump stops.
2. The rear TA bushings are too soft. It can make the rear of the car less predictable that it should be.
3. Its too heavy for the stock 225s in the front.
4. Brakes. Our local roadcourse is not at all hard on the brakes so the stock units are enough for me here. Depending on which track you go to they may be the first thing you need.
I got my M3 in January. I have been autoXing the car to learn to drive it and find its limits in a safe enviroment. Here is what I found and what I did each step of the way.
1. I bought Dinan sway bars front and back. I wanted to reduce flex as much as possible to avoid developing squeaks latter.
2. I drove the car nearly completly stock save #1 at the first event. It was a big adjustment from my old 328is.
3. I picked up a second set of rims. SSR Comps 8.5x18 front and 9.5x18 rear with Kuhmo V700's for the events.
4. With the new tires it took a bit to adjust. My 2nd event was a disaster. I nearly spun the car on my first run. The breakaway of 'R' tires is very diffrent than street tires. I worked my way up to 4th in my class. I had managed 3rd on street tires at the first event. I continued to run events on the 'R' tires and basiclly cemented myself into 2nd place in my class after the next several events.
5. One of the big problems I was having was powering out of turn in 2nd gear was producing nice looking drifts that were not very fast. Aslo during quick transitions the rear of the car got real lose real fast despite all the understeer everywhere else. I purchased TC Kline trailing arm bushings and lower control arms (rear). This solved the stability problems with the rear suspension. It did make the car harder to rotate at times but allowed me to focus on my driving.
6. With the changes I slowly improved with the car. I also managed to get a couple national level driver to drive the car at events. After 5 or so events I formulated my next step.
7. I ordered the rest of my syspension. I went with the GC "street" struts with their racing sway bars. I wanted linear springs, the kits you mention do not have that option from the places I contacted. I also replaced my front rims with wider 9.5" untits.
8. I took the car to a test & tune and setup the front and rear camber on the skidpad. I also set the preload on the sway bars and used the bars to ballance the under/over steer to my taste. I then tuned the shocks on the test course. By the end of the day I was only about 0.5 seconds behind the fully race preped ~2300lbs rx-7 (one seat, no interior) on the ~21 second test course.
9. I managed some good times with the new parts though my day was cut short by a pair of bolts that came lose on the rear sway bar.
Here is the current setup of the car.
TC-Kline TA bushings
TC-Kline lower rear control arms.
GC front coil-overs with eibach #450 springs and Koni DA shocks.
GC front camber plates.
GC rear ride height adjusters
Koni SA rear shocks
Eibach springs rear #500
GC front and rear sway bars
Dinan front and rear strut braces
Let me know if you have any questions. I would not buy progressive springs IF you want to set the car up for the track.
Last edited by Enigma; 2nd September 2002 at 21:46.