newbie coilover questions...

[zredbaron]

I finally can afford to put in the suspension i have always wanted! I had originally planned on getting eibach progressive spings with the tokico illumina struts, but from browsing i see these coilovers from modern motorsports, which look awesome.

 

I am under the impression that progressive springs dont get put in the coilover kits, is that right? why or why not? my Z is primarily a street performance car, but i want to be able to take it to the track/autocross and still be competitive. my previous research indicated to me that i should go with progressive springs. any thoughts on this? if putting these on coilovers is a no-no, then what spring rate would be appropriate for my application?

 

thanks for the help.

mark

[ToplessZ]

Wish I could Help I was just wondering the same thing myself after just reading an article about progressive rate springs in car craft??? Someone will pipe up here....or else

[Guest 81na ZX]

Coilover kits use linear rate springs.

 

I've heard a couple reasonings:

#1 - Hypercoil and Eibach (the 2 major race spring makers) springs meet spec'd rates within like 1%. Progressive rate springs (even eibachs) vary.

#2 - Progressive rate springs aren't bought with speficic rates

#3 - Progressive rates sag. Race springs shouldn't sag much (but i've heard of Eibach's that have)

#4 - linear rates are easier to "tune". When you corner and the spring rate jumps, its harder to have the right settings for the whole corner. (Like thats really possible on many tracks)

#5 - Because you can specify rates of linear springs, they are easier to tune, and cross platform - My talon has 400lb/in and 350 eibachs on it, and the Z will have ~200s on it, but they are otherwise identical springs.

#6 - Race springs don't "go bad" as fast thus if you don't like your present rates, they are resellable. And you can find used springs.

[Guest DISCUS]

I have experience with tokico illumina, modern motorsports set-up. I use it on the street and auto cross all the time. The beauty is the adjustability of the illumina,s for ride and the adjustability of the coilover setup for ride height. I am using 175 lb front and 225 lb rear. My car is lighter than stock with an LT1 for power. Balance is 49% front and 51% rear. You may wish different spring rates depending on your cars overall weight and Front to Rear ratio. This setup works perfect for me. It is very nice to be able to raise the ride height and soften the shocks for long distance highway travel and every day comfort then stiffen the shocks and lower the car for serious playtime.

[JMortensen]

I do like Discus said. I've corner weighted my Z and I know how far from the perch the adjusters need to be to balance the car at race height. At race height it becomes hard to drive around town, so I go to the track swap tires, adjust ride height, and adjust camber, then turn up the Illuminas, then run. It's about 1/2 hour worth of work, so I just get there a little early (or try to).

 

As far as progressive spring goes, I think the best argument against them is that you are GUARANTEED body roll, until the suspension goes through the soft spring. Once you hit the harder spring rate, then your "real" rate begins. If you are racing and you are in a long bumpy turn the suspension will be into BOTH spring rates as the body of the car bounces up and down, and it can make your handling really quirky. Not too long ago we were talking about this and someone had mentioned a kit with progressives in the front and linear rate springs in the rear. This seems like the ultimate bad spring idea for a race car.

 

Jon