E46 M3 auto-x setup

[snaponbob]

I have competing over the past 6-7 years in first an E36 328 and then an E36 M3 in SCCA ST classes. Similar setups worked very well and the car was a competitive as those could be in their classes. Now, I am moving the STU with an 04 M3. In driving each in first stock trim and then prepped trim, the E36s were basically identical in the traits (accounting for basic suspension and power differences. When "built". other than the influences of power differences, they were essentially identical. The E46 is a much different animal. Power being the huge difference, weight has some influence as well.

Withe the 36s, I learned on the fly and continually altered the suspension setups, almost always making them better. This time, I want to hit the courses with a set up that is far closer to a "finished" product than the 36s so as not to waste time and money throwing stuff at the 46.

If there are some folks here that have dialed in the 46 M3s, I would like to know what your final spring and bar selections are. Track or Solo data is equally welcome. My basic plan is GC D/A's with yet to be determined bars. The car will go up on jack stands next week for the start of the build.
Front subframe will be reinforced
Rear subframe will come out for body reinforcement plates
Rear subframe will receive all new ball joints and poly upper/inner bushing and adjustable camber arms (HUGE difference in the E36 M3 !!!)
ALL poly bushings everywhere

So, looking for spring and bar rate suggestions. Not worried about street feel. So -- fire away.

[lowflyer]

I'm running 650f/750r springs,30mm H&R front bar with stock rear bar and MCS 2WNR suspension. Car is otherwise stock so nowhere near fully prepped but works exceedingly well for both autocross and track. The top nationally competitive E46 M3 STU cars are running 650f/800r springs with a similar front bar on MCS suspension and are fully prepped.

[snaponbob]

Huh. Raising rear spring rates and similar front bar (they are NOT all the same !!) sure would loosen up the car. MAYBE good for Solo but terrible for track. That said, some others have mentioned the 650/800, including Ground Control.

On my E36 M3, the best setup was 650f/700r, 30mm f/22mm r bars. I ran a LOT of camber (4.5f/3r) and it worked. Never could keep the inside front down, but I did get it tuned to not fly too high. With the additional weight, width, and power of the E46 M3, I may start with something like yours. Rear springs and front bars are not too expensive.

[badmonkey]

Huh. Raising rear spring rates and similar front bar (they are NOT all the same !!) sure would loosen up the car. MAYBE good for Solo but terrible for track. That said, some others have mentioned the 650/800, including Ground Control.

On my E36 M3, the best setup was 650f/700r, 30mm f/22mm r bars. I ran a LOT of camber (4.5f/3r) and it worked. Never could keep the inside front down, but I did get it tuned to not fly too high. With the additional weight, width, and power of the E46 M3, I may start with something like yours. Rear springs and front bars are not too expensive.

700/850, big GC front bar, stock or small GC rear bar on my e36, for track. Much prefer the 150lb split over the 50 or 100 lb.

[snaponbob]

Thanks. My 36 is sorted --- and for sale. I am focused on the 46 M3. They are close, but knowing how 36s (any of them) handle, vs the 46 M3, the setup will be different.

[lowflyer]

700/850, big GC front bar, stock or small GC rear bar on my e36, for track. Much prefer the 150lb split over the 50 or 100 lb.

I wouldn't hesitate to try a 100-150 f/r split - or stiffer rear springs. After years of running AST 4100s with 550/650 springs and same front bar and constantly struggling to put down power on corner exit it was immediately resolved when I upgraded to the MCS 2WNR dampers and the availability to adjust compression in the rear especially. Being hesitant to go too stiff in the rear, testing revealed that as I added more rear compression the car only got better in any phase but especially on exit. I had equal concerns when going to 650/750 springs but the car actually got better although I did end up reducing rear compression by two clicks. I plan on trying a 150 split next year and will probably try 650/800 springs first because the rears are so much easier to change. Front bar set on medium since going to MCS FWIW.