I'm considering a set of GC springs and Koni shocks, mainly for a street car that will see some auto-x and track days. I like the idea of adjustability, I'm also swapping to a LS3 which means more than likely I would have to cut the Eibach springs I have now (which I did when I went alloy heads and tubular k-member with the TPI motor).

Just seeing who runs them and get some recommendations.

Thanks

 

We ran 1100 lb front and 225s on the rear for several years with quite a bit of street driving. After about 5 years the GC units were so bent where the bolt meets the upper cup, we had to replace them for safety reasons. Both UMI and DSE use thicker steel in the upper cup to prevent this from happening. If you haven't order from GC already, I'd take a look at those 2 options first. UMI has both front and rear weight jacks and sells Koni shocks. DSE has just the fronts for weight jacks and also sells Koni. Either can give you some good advice on setting up your car.

 

That seems very stiff for the street, i was planning more on something in the 800 lb for the front, and thanks for the info

Mike

 

The owner of Blue Coil died so Ground Control can't get the same springs any longer. They still have old stock remaining but once old stock is used up they likely won't have as many choices.

I just received some new rear springs and it is Eibach of different spring rates and different kind of construction.

 

My ground control weight jacks that I recieved about a month ago use eibach springs. After several phone calls with them, I determined a 950 lb front rate and 200lb rear rate would be appropriate. The guy I spoke with also has a thirdgen and after listening to my plans for the car and what I wanted to do, recommended these rates.

My advice is to give them a call and discuss your car and plans. They are really nice guys and very helpful. Took their time to understand what I was trying to do before helping me with my decision.


I went with their full kit which includes their custom valved front struts. Very nice setup overall from my initial impressions and installation. My car is getting aligned this weekend as I finally got everything put back together. I can add some additional insight once I get to drive on them a bit.

 

How much street driving will you be doing and what condition are the roads in that it will be driving on? I also have 950 front and 225 rear springs along with rod ends on everything. Here in the Southwest the roads are usually in great shape but we still have bumps, manhole covers, pavement transitions and road repair areas and I'm here to tell you that the ride is still jarring. I rarely drive the car and I like the way it handles so I live with it but if I drove it 100 miles per week in the summer or lived in an area where roads needed to be repaired after winter I wouldn't go above 800# front. I also have the UMI weight jacks and they are nice pieces but I think I would have been better off with purchasing a set of springs from Eibachs racing spring catalog. For my driving capabilities they would be just as good and the setup would be less expensive.

 

Ground Control tried to talk me in to the 1000 and even 1200 lb/in springs when I bought my set up. I thought they were nuts!

I asked for 800 lb/in front and 175 rear. Let me tell you, even that is pretty harsh on the street at times. Shocks matter a lot when it comes to ride quality. But there is just no getting around the fact that some suspension travel is a good thing.

They sent me 9" tall springs (free length) and that is too short when you've got the lighter spring rates. The rear jacks were maxed out with the car sitting fairly low. I have since gone to 11" springs in the rear. I left the front alone because it's not bad enough to warrant spending the money.

 

Hypercoils. If they don't have what you need....

 

I've had Suspension Techniques, Hotchkis, and Hypercoil. In every case the rear fishtailed badly when tires spun. The car would go any which way but straight. It was dangerous!

The constant rate springs with the weight jacks keeps my car going straight as an arrow with tires spinning through 3rd gear. I think it's the predictability of the constant weight springs, and the ability to corner weight the tires to get the results.

 

For the front, is that an 8" spring or a 9.5" spring?

 

I'm using 950lb front and 250 rears. I have a lot of weight removed from the front.
With good shocks, koni yellow, its firm but not harsh. Actually comfortable. Very happy.

 

9 and it is too short. But at least it doesn't fall out on its own like the back did.