Originally Posted by 335igawnM3
Back to suspension if I may, sway bars; any input on them? My plan for next season is pads and fluid. I thought about ZCP springs but from what I learned from you karussell, I may pass on them and keep the oem springs for now. My question is I notice sway bars aren't popular with the M3 e9X however, I've been told they are used for "fine tuning" the suspension (assuming aftermarket suspension). What's your take on sway bars and can it be an worth while purchase to use with oem suspension? I learned how good the oem suspension is so my money is going towards more track time and possible driving school. I just have this itch with sway bars that needs to be scratched...
ok so just like any other suspension component its entirely dependent on the condition its applied in.
A suspension's job is to maintain maximum tire contact with the road. An independent suspension allows the left and right wheels to do that job separately. This is crucial on rough tracks. A sway bar artificially increases your spring rate but the take away is it also lessens that independence.
Going to a stiffer sway bar on a rough track such as the ring may have some negative consequences like making your car want to snap oversteer when you hit a berm such as in hatzenbach on the right.
the oem sway bars are adequate i think for the ring. if you want to scratch the itch and just want a pretty red bar, then i suggest you pick the softest setting.
now if you want something that is useable my advice would be ground control's coil over conversion kit. they use the oem shocks if you have edc. you can pick the spring rate. its linear eibach springs which is great. make sure to tell them you are running the nurburgring so they pick out the appropriate spring rate. you don't want them too stiff. the best part is you get ride height adjustment independently on each wheel. you MUST get the car corner balanced after getting these. that will be the most significant change you will feel in the seat of your pants with a properly matched spring and corner balanced. when you feel the car is planted firmly you are more confident in it.
again, if you are worried about any suspension components then you already should have upgraded the brakes. that means 2/3 in a lap on the ring your pedal is already mushy and going to the floor or 15 minutes into a single 20 minute session on the gp track. if your brakes haven't done that yet, you aren't going fast enough yet and the suspension is definitely not hindering you any.
of course this doesn't mean you need to go out and try to abuse the brakes. i'm talking a legitimate lap and you routinely have to wait for the brakes to cool in order to use the car again. at that point you are ready to upgrade just the brakes. after that pick the tires you plan to track with. i could write pages on tires too. once you got your preferred tires and brakes settled and you have tried everything possible to improve your lap time (by technique) but can't get past it then i suggest you have a coach. after that and you still can't get any more out of the car then you touch the suspension. that is how good i think the oem suspension is on the ring. remember that suspension was developed on that track by BMW engineers with over 25 years experience on M3's.