DirtySpleen

So I've grown tired of slamming my nose into the ground over every speed bump, so I figure its time for new non 175K mile suspension parts. I have a 1991 Camaro RS 305 for the record. I am very big on autocross and drift racing at the local speedway, so I need stiffness, and ride squishiness is not a factor in my choices. Ive heard Eibach Sportlines in a very stiff rate are a good way to go, not sure on the difference between them and the Prolines minus the ride height. Help?
For shocks im not as certain. Ive heard good about Koni Yellows, But also they are on the pricey end. Still an option though. Ive heard good about KYB but im not sure how they would perform in an autocross world instead of the weight shifting drag world. Any help on this guys? Thanks!

LsxMatt

iTrader: (4)

Im due for rear shocks right now. Im running eibach pro springs, with regular kyb gr2 shocks in the front and rear. The fronts are holding up, but the rears are done after about 5,000 miles. Bottoming out on the bump stops, and there covered with oil. I don't think there designed for a lowered suspension, it seems like the KYB AGX would be much better.

I personally decided to go with Koni yellows. Gonna start with the rear then do the front later. It seems a lot of autocross guys run them I haven't heard a bad thing about them myself. My car is my daily with some strip, and everything i read about the konis says there amazing. I don't think there too much more than the kyb agx either, if your looking for an adjustable shock.

DirtySpleen

What sort of spring rates do your pro kits have? How do they feel and handle in terms of nose dive and body roll under harder conditions?

LsxMatt

iTrader: (4)

Here are the springs I'm running:

http://www.summitracing.com/parts/ei...ro?prefilter=1

Some complain about the rear springs being too soft. Like i said, my car is my daily, so I'm not under autocross conditions so i can't really say. As for on the street i like them. The car stays flat through the twisty stuff and the ride isn't terribly hard. Im also running the cheapest kyb struts u can buy, pretty much stock replacement stuff, v6 sway bars, and no wonder bar, so its only gonna improve from here.

Nose dive really isn't bad. I just put ls1 brakes on my car, and the rears aren't doing much so i have more nose dive than normal, but with the stock brakes there wasn't any. Once i get an adjustable proportioning valve it should be an issue.

midnightfirews6

iTrader: (1)

Sportlines are actually not stiff enough for the amount of drop they give. For drifting and autocross, the best off the shelf springs are the Eibach Pro Kit... but it only drops about 1" from how high the car sat when it was brand new 175,000 miles ago, so it may not drop much if your springs sagged over the years.

Pro Kit: 714 lb/in linear front 1 inch lower front
109/177 lb/in progressive rear 1 inch lower rear

Sportline: 700 lb/in linear front 1.6 inch lower front
80/137 lb/in progressive rear 1.3 inch lower rear

Your other options are cutting MOOG springs to spec or weight jacks. Plan on a 5:1 front to rear ratio and shoot for at least an 800# spring rate in the front (which with the ratio would pair with about a 150# or 175# in the rear). Cutting MOOG's is the cheapest option and will give you all of the performance you could want if you calculate the height and rate you want to end up with and cut accordingly. Alternately, weight jacks allow you to simply whatever spring rate and length you need and you fine tune your ride height with the adjustable spring perches. You can also get the car's chassis x-weights dialed in if you have access to corner balancing scales or service. They're definitely the most expensive. If you want to learn more about making your own do a search or Google "Ground Control suspension" for an off the shelf kit.

Shock/ strut wise, get Koni. They're a bit pricey but no one who's waited and saved up for them has ever regretted it and wished they'd bought the cheaper ones.

DirtySpleen

Great info, thanks!

plum92_camaro

I agree with everything midnightfirews6 says. He and I have almost identical set ups. I only have the front done so far. It's all listed in my vB garage.

Koni's are the way to go since you autoX. All the best autoX/RR cars run them. They will handle the higher spring rates you will need. Bilsteins are pretty good too i hear. People usually have them custom valved for the springs they get.

Cutting moogs is a cheap, but effective way to go. Make sure no matter what springs you decide on, get constant/linear rates, not progressive/variable rate springs. Weight jacks are pricey but they are the ideal spring set up for these cars. Don't consider coil-overs.

I'd like to suggest another option for springs that I was considering before I decided on GCWJ. It should cost in the middle of Moog and GCWJ. Use some Eibach pro-kit fronts, but don't use the rears. Eibach rears are progressive rate. For the rear use Global West S40 springs. They are 190# constant/linear rate springs. If you want the car lower cut the springs 1/4 coil at a time. Every time you shorten the spring the spring rate goes up.

DirtySpleen

If I got a pair of Moog rears, what part number am I looking for to get the desired spring rate, and how much would they need to be cut to equal the Eibach fronts?

Alice89

iTrader: (6)

Moog 5665:
http://www.summitracing.com/parts/mog-5665/overview/

They still are not a great spring rate; but once cut the spring rate will go up. They are better than the sportlines rates.

Due to differing car weights; there is no universal way to determine how to cut springs for the desired ride height. You will just have to cut a 1/2 coil at a time until you get the desired ride height. (I would cut a half coil at most each time so you don't over cut)

plum92_camaro

Maybe only cut a half coil the first time then go quarter coil each cut after that until you get it where you want.