spring rate and sway size input

[fastboy559]

Coming to the point were its time to order suspension....car will be intended for spirited driving autox and track days

setup
koni/ground control, unsure of rates
m20
coupe
no rear interior
no sound deadening
spare tire carrier cut out trunk smoothed
roll bar
condor bushings everywhere
not sure on tire size yet nothing to crazy

what is everyone else running thanks guys

[mulletman]

I have H&R "race" springs and UUC 22/19mm sway bars. I like the size of the sway bars, but I'd steer you away from the UUC kit. Based on the shortcomings I've experienced, I'd recommend the Bimmerworld sways. The only company that offers bars bigger than 22/19 is IE.... so that should tell you something about how beneficial huge sway bars are.

[fastboy559]

ive heard that higher spring rates are better than bigger sways

[Mr. Tasty]

ive heard that higher spring rates are better than bigger sways

correct, and this has to do with the crappy mounts that bmw engineered.

[mtech325]

ive heard that higher spring rates are better than bigger sways

I'm sure there's going to be a bunch of different opinions on this, but here's my take on it:

For a street car, you're going to want to have a bit of compromise, so this is where beefier sway bars come into play as you can retain your ride quality and spring rates that you prefer or already have. That being said, the bigger the sway bar, the less "independent" the suspension becomes.

A higher spring rate is always a good start, and THEN move on to fiddling with sway bars. I like to think of a sway bar as the cherry on top of a good set of spring rates. If you're going to go the GC/Koni route, the popular set up seems to be 440 lb front, 650-700 lb rear. Since you're gutting the car you may want to adjust those rates accordingly, but it's certainly a capable suspension that behaves well on the street. If you want to go a step further, weld on m3 style front sway tabs to the housing and get more use/leverage out of your existing sway bar. Just my

--Joey

[mulletman]

Also consider the fact that the higher your spring rates go, the less effective your sway bars become. The job of the sway is to compress the suspension on the other side of the car... and if that spring rate is way higher than stock, you can also assume that the stock sway will be significantly less effective at compressing it.

[fastboy559]

Beefing stuff up is not an issue I am a fabricator by trade and specialize in performance automotive.... I want the car to work properly and I have always heard spring rates over sway size... I'm very familiar with what a sway bar does and making it so it won't break ... I'm just trying to get some input on what people are running and why, and if they like it...I don't want to get beat to death but a firm ride is fine when I turn the shocks down...I want to be able to track the car and not wish I had more spring.... But I'm not gonna be running some crazy tire either so I would think I wouldn't have to got high

[jlevie]

If the car is to be a track rat, higher spring rates are what you want. My Spec E30 uses H&R race springs (315/570) with 22/19mm sways (from Bimmerworld) and the suspension is quite soft for the application. Spring rates up around that of TMS J-stock (680/1026) would be more like it.

Talk to Ground Control they will be able to help with picking the spring rates.