Racing Suspension

[Driver726]

I'm building an E36 Track car and I was thinking of doing a custom set up from KW but I am unsure what spring rate I should tell them. I dunno if I should go balls out and say 1000lbs/in or what? I'm not sure how much the chassis can handle. Let me know what you guys think. Thanks!

[spidertri]

I honestly have no idea, but please, start a build up thread, lol. I'm sure some of the other guys on here can give you an answer.

[gimp]

You need to do a lot more research before you just start throwing spring rates out there. They have to match what your shocks are valved to handle, and the other mods for your car.

Check the track section of the Bimmer Forums for advice.

[1996 328ti]

Too stiff is not necessarily a good thing.

[mohaughn]

As somebody else mentioned, I'm fairly certain KW shocks will not handle 1000# springs... You will also have issues with the swing arms and shock towers possibly warping a bit from that much spring. You definitely need to re-inforce the chassis to go that high. Springs in the 600-700# range are more than enough and you can find several of the better shocks brands that can handle that range... You probably need to talk to TcKline, Vorshlag, Groundconrol, or Bimmerworld to make sure you have the proper valving in whatever you buy. Not sure that KW will even go up to 700# with their normal coilover setups.

You should probably expect to spend something in the 2000-3000 range just for coilovers and shocks if you want a decent amount of adjustability, and you want to handle high spring rates. Regular old koni's can only go up to about 500 or 600#. TcKline revalves their koni shocks to handle 700-800#.. And ground control can build whatever you want.

[Driver726]

Yeah after doing some research and checking out other set ups I see 800 is usually about the limit of what everybody is running with mostly stock chassis components. I'll definitely still be beefing up the chassis even before I start running that much of stiffer suspension. Ground Control is what I decided on instead because I only hear good things about them and they are half the price of Motons. Thanks for your help guys.

[mohaughn]

If your not actually racing and trying to get every last second out of the car, motons are probably overkill. Never heard any complaints with GC stuff.

[gimp]

what type of racing?

[Driver726]

General road course... don't have a specific class in mind just yet.

[gimp]

Figure out what class you want to run, then make modifications. You don't want to end up in a class you can't compete in.

How much experience do you have? You may want to invest some of that suspension money in Driver Education.

[Driver726]

I have an idea of what I want to do, but I'd rather just make this a fun project rather then worrying about rules and restrictions. This is just a weekend project, its my first project car and I'd rather have it be relaxed. I'd rather redo the car later then not do it the way I want to now. And driver education is in the budget as well as suspension. Besides the front shocks are blown, so I'd have to replace the suspension first anyways. Thanks.

[gimp]

If you are just looking for a fun project that will handle well on a road course, and be versatile, and not kill you on the street (I assume you aren't trailering the car), call up Ground Control. Get their setup with Koni SA's and have fun. Once you know where you want to be, you can spend the big bucks and upgrade to a more specific setup (not that the Ground Controls are a bad setup at all - plenty open track on them).

[Driver726]

Alright thanks. I will be trailering it though... I'd rather not drive it then spend the registration and insurance on it haha. Thanks gimp, you have been very helpful.

[gimp]

Invest in a set of Vorshlag camber plates while you're at it.

[mohaughn]

As long as you don't go with a three or more-way adjustable suspension, and you don't use a shock with a remote reservoir you will probably not outclass yourself from the lower SCCA, NASA, and BMW- CR classes. If you just want to have a nice dependable car to learn with, I'd get yourself a nice GC setup with moderate spring rates and go from there. I was in the same situation as you. I ended up buying the TcKline DA coilovers, and honestly, they were probably overkill for the first year or so. But after doing a year of DEs with the suspension I have definitely learned to use it to its potential, and it was nice to just have it done in one shot and not to have to redo anything. I have made very little adjustments to my suspension in the last 18 months. It has actually taken me this long to get comfortable enough with the car and the setup to feel like making small adjustments. I really feel like in the first year I didn't know enough to even tell what differences the changes in suspension settings were making.