GC spring length/rate?

[wazzu70]

I tried the search but was not coming up with anything that really answered my questions. First off Im pretty sure the IE3 springs that I ordered are not going to come in so I am now changing gears to go with the GC setup. Because I was planning on going with the IE springs I just got the regular Koni sport front strut, not one that was made to accept a shortened strut housing. I am curious as to what length of spring (front and rear) would be best for this setup as most of the threads are based off spring rate and not length.

This car will be my daily and will hopefully see maybe a track day or two a year just to give some insight. I live in Seattle where the roads suck so I definately do not want ultra stiff springs or a really low stance. My goal is about a 1" drop in the rear and about a 2" drop in the front which I think is achievable with the Koni setup I currently have. I am thinking of going with rates of 350 lb/in front and 475 lb/in rear incase anyone wants to comment on that selection as well.

Any advice on spring length or rate appreciated. Also is going through one of the vendors of GC products a lot easier than going through GC themselvs as their customer service blows. Thanks in advance.

[IS]

Call GC and specifically ask for dale. I know their customer service sucks, but that is because every other call they get is ricers asking if they can lower their cars 3 inches and still get away with stock dampers.

I'm running 440/700 (6" and 5" respectively) and its not really that great on bumpy roads, but it gives you an idea on the ratios of front to rear. 300/500 will be better than the 350/475, since the latter will give you too much understeer.

In my suggested rates, 7" 300# springs and 6" 500# springs will work.

As for justification for my front/rear springrate ratios, Turner's j stock springs are .66, hr race/ie 3 are .55, hr sports are .53. 300/500 is .6 and my setup is .63. 350/475 is .74!

Further reading: http://e30m3performance.com/tech_art.../eff_rate2.htm

[cheades]

I would agree with IS, I have 440/625 and they can be a bit sketchy with some of the crappy pavement at Pacific Raceways (t2 bumps, t5a hump). Better off if you have done much for track time to start off softer and then change later to a stiffer setup. The only time the springs really bother me on the street are on quick bumps, they are really harsh but the rest is ok.

[wazzu70]

Thanks for the input guys. The ratio information is really helpful to me in selecting some spring rates. Also the length information is great as well, as thats what I was looking for.

Ive read that the 300 lb/in front springs are a little too soft so I might try and go with 350/625 or something of that nature. I am especially afraid of getting too weak of front springs and bottoming out since I am not planning on cutting the strut tubes at this time as my dampers are to be used with stock length tubes. Yes, I have the foam bump stops so hopefully that will prevent damage.

Cheades or IS, I am assuming you are running with the cut strut housings?

Again, thanks for the feedback.

[IS]

Nope, stock length strut housings. I'm using custom bilsteins though, with a shorter compressed length.

[dirty30]

In my suggested rates, 7" 300# springs and 6" 500# springs will work.

perfect.

[Low Level E30]

Call GC and specifically ask for dale. I know their customer service sucks, but that is because every other call they get is ricers asking if they can lower their cars 3 inches and still get away with stock dampers.

I'm running 440/700 (6" and 5" respectively) and its not really that great on bumpy roads, but it gives you an idea on the ratios of front to rear. 300/500 will be better than the 350/475, since the latter will give you too much understeer.

In my suggested rates, 7" 300# springs and 6" 500# springs will work.

Will these spring lengths allow you to get the car down reasonably low (not slammed, but low) ? Or do I need to go w/ shorter springs?