http://www.ground-control-store.com/...hp/II=20/CA=86


Guys I'm going to be getting these shortly and I need a bit of help as to what spring rate I should get. They have options of street, aggressive, or race... or I can have them email/call me to discuss it? I want to run them kind of stiff.. I don't care much about ride quality as I'm more concerned with not bouncing around with these shitty nwi roads and potholes lol... ill also only be lowering about an inch/inch and a half... what would be my best spring rate? Should I have them call and specify a certain rate? Thanks

 

anybody... anybody at all lol

 

Spring rate depends a lot on the type of shock, type of driving, weight of the car, how stiff do you want the ride, etc. There isn't a set answer for this. Are you planning on competing in autox or road racing with the car? Is it just to give you a lower stance for a street car?

 

Pretty normal driving no autocross.. I just want a slightly lower stance.. and I don't want to be bouncing around at all especially since ill be lower and I don't want the car to scrape if I hit a bump

 

I'd recommend just using a set of lowering springs from a company like Eibach then. You don't need the adjustability or higher spring rates the weight jacks will give you.

 

I like the adjustability cuz idk exactly how low imgoing once I get new wheels and I want to be able to go higher in winter as this is my daily

 

Every time you change the ride height you will have to get it realigned. It changes camber and toe to change ride height. I agree with beater79ta. For a street car I would go with eibach pro kit or cut moogs. But if your set on GCWJ I would say 700/150 would be good for you. Eibach prokit are the same rate.

I designed my suspension for the track and I have 850 fronts. They are VERY stiff. You wouldn't like them on a rough roads and potholes would be a nightmare. I haven't installed the rears yet but they are 250's but I will exchange them for 200's before I do the rear. FYI, I run Koni yellows.

 

I bought some just before the new year. If you do decide to go through with them don't email. They didn't reply to any of mine for like 1-2 months. Call the number on their site then price match with Sparktecmotorsports.com ($413usd). I called and told them and they had no problem giving me 10% off. Then only charged $18 to ship instead of like $55 or whatever the website lists. Very nice pieces I must add. I was going to build them and the savings doesn't offset the fact they are nicely powder coated and have grease inserts for the threads rods.

I went with 800 front 175 rear since the car is just a weekend/toy car that I plan on trying a few lap days this year.

If guys on here are correct, stock iroc-z fronts are around #700 and rears #150. I also recommend if you go this route you look into strapping the rear. If jack/lift the car not by the rear end the springs can fall out due to them being so much shorter than factory. Ive posted about strapping/limiting rear end travel in case something on the street happens and no-one seems to be worried about it. So that's up to you. I like the piece of mind that I cant over extend and lose a spring on the street. There are some wicked train tracks/hills around here on the county roads. You can get Suspension Limiters from Summit for like $50. Whenever I get back into working on the car I will make a how too for that.

Jay

 

Alright thanks for the help guys I appreciate it a lot and that's a good point about limiting the suspension travel so the springs don't pop out thanks for bringing it up I'm going to look into it

 

That reminds me, I would also recommend if you get GCWJ, get the longer springs. i got the shorter ones and full low is too low. It will sit on the fender liners. The higher you adjust them at a certain point you only increase preload on the spring and decrease the springs travel range. I'm not unhappy with the ones I have but I think I should have got the longer ones. When jacked up the fronts were loose at full low and would unalign with the cups in the top of the kmember. i adjusted them longer and they fit just perfect. then i set the car down, rolled it a lil to settle things and started adjusting to height. i used a digital caliper to measure the adjusters to get them even. I am very pleased with how things turned out.

I can't imagine the rears needing strapped once they are adjusted/extended to ride height but i haven't installed my rears yet so i don't know.

 

Agreed... 9.5" are a better choice than the 8" springs.

The rears do come unseated when jacking the car up. Not a big deal, mine have never fallen out. I'm running 8" front and 9" in the rear with the adjusters at like 1/3-1/2 way up in the front and fully down in the rear with factory rubber spring isolators in the rear on top of the springs.

How it sits:

 

Looks good! And you got LOUVERS! I got the same wheels in chrome on my donor car but haven't decided if I'll use them. Mostly cause one is broke and I don't want to buy a wheel and spacers to complete a set I don't love. Your car makes them look good. Weren't they black when you installed the GCWJ?

 

I just wanted to say that your stance looks great! I love that two tone paint job too. Great looking early Trans Am!

 

Thank you! I hear you on that, no point in running something you're not crazy about. You could probably sell the ones you have as spares or something and pick what you really want up since they seem to sell pretty quick.

And yes they were, they were my first plastidip experiment a few years back. I was going to redo them in anthracite grey (got tired of friends and family telling me how black wheels look like old steel wheels or like they're covered brake dust) but I just never got around to it.

Also, I realize I didn't clarify to the OP (or anyone else) in the above post: I recommend the 9.5" springs in the front. 9" in the rear for sure, you can get pretty close to stock height with the isolators installed. A taller spring wouldn't let you go as low though. For reference, my adjusters in the rear are totally bottomed out at the height I'm at, though if I pull the rubber isolators it'd probably be another 1/4"-1/2" lower. Obviously spring rates and car curb weights will have some effect on this, but for most average street rates (700/150, 850/175) in an iron v8 third gen the difference shouldn't be that huge.