Hey everyone, I am looking to purchase Ground Controls and Konis for the S ($900shipped) and was curious as to everyones opinion reguarding spring rates and front and rear bias.

with this in mind:

OEM Spring rates by year (front/rear)
MY00-01 = 218/291
MY02-03 = 240/230
MY04-07 = 256/207 (I'm getting conflicting info here)
MY08-UP = 274/225
MY08 CR = 375/264

The standard rates from GC are (340f/380r) or vise versa.

The Koni yellows can handle up to 500lbs/in before needing revalving or modifying.

The use for the car will be primarily daily driver (for now) and look forward to getting into some autox and eventually to Sebring or Daytona I have track experience with Skip barber and Panoz racing school, as well as a RSXS school after HS graduation.

Opinions and comments are welcome, as well as your own personal rates and reviews. *i dont mind a stiff ride*

Some rates ive gathered from the site are:

425f/400r
380f/340r
340f/380r

 

I would post this in the Racing & Competition forum. Many track junkies there who can give excellent advice on spring for the purpose you have in mind.

 

I've run 380's at all four corners on OTS Yellows. I've run 500F/550R on those same shocks. I have never run either configuration without my Gendron FSB. I just had the shocks revalved and made double adjustable. I've elected to go 650F/550R for now. I guessing I'll end up going 750/650 down the road, but I will let datalogging/video determine that.

The 380's are very streetable. The 500/550 setup is noticeably stiffer/bumpier on the street. My track experience with them is that 380's are not nearly stiff enough for R-compounds. If you're not running a wing for the track, I'd use stiffer springs up front. I do not know how much of a difference needs to be front-to-rear in order to feel a difference. It is probably a percentage versus a hardline difference in spring rates.

This is just one man's experience/opinon.

 

thanks FF for the response. Im all stock, no rear wing. and will not be running R-comp on this suspension set up most likely.

the 08 CR front bias is 375/264 = 1.42 (wing)
the 08 is 1.2178
the 04-07 is 1.236

In order to keep the percent the same (read: close) while increasing rates from the 380s, it would need to be 480/400 or 500/420 or so. ??

All of the big name coilovers BC racing spec, tein src, J's, t1r, etc seem to have equal front and rear rates, 10k/10k, 12k/12k, 16k/16k? Is this because it is assumed they will have a rear wing for downforce on the track or that they dampening can be adjusted to such an extent that it is beneficial for such stiff springs?

 

What you can also do is call GC and tell them how you want your car to react,ie street driving, autox or track, and they may be able to point you in the right spring rate direction. I also read here using search and found my spring rate but I called GC and inquired there and they gave me some reassuring info for what I wanted for my driving and what I wanted from my car. Then I ordered from them......425f 400r for a 2002.

 

thanks billy, i did pages and hours of reading the past few nights. lol

your actually who i was referring to when i said i saw the 425/400 rates.

how do you like them? too stiff, too soft, better than OEM?

what is your use for the car? street/track/autox?

THANKS

 

I originally keyed "with" instead of "without." I have corrected it.

 

Really good luck with them as well.

 

I've had these in for the past 3 years and yes, the Ground Control sleeves with the Eibach custom springs in conjunction with the Koni shocks is, to me, the best set up for the money and performance. damn i sound like a commercial. didn't mean too though. I thought about PSS9s but spring rates are lower.

 

billy, what is your use for the car? street/track/autox?