C Murda

iTrader: (24)

i have an 02 z with 29kmiles on it and after installing the springs ive noticed if i push down on the car it will bounce up and down as if my shock were absolutely blown? feels like my bimmer with 179k miles and stock everything!!! cardoes seem to handle better just a little bit bouncy. is this normal when lowering with stock shocks? should i invest in some Koni D/As? i am building my suspension but was hoping to wait off on the $1300+ price tag of new Koni Sport Yellows....
what about different springs? i want the ride height of the sportline but will go a little bit taller if thats my only option. have heard good things about DMS springs, where can i order those? how much will they lower my car compared to the sportline kit?

trackbird

iTrader: (4)

The sportline kit is generally considered to be too low for performance applications. It's also too soft for as low as it is. So, it's really an appearance only kit and pretty much will place you right on the bumpstops (or very close to it). I'd consider raising the car a bit and matching upgraded shocks with the next springs.

ChoiceCam00

What do you mean appearance only kit, alot of F-bodies use the Sportlines with an upgraded shock and strut. If you use the stock shocks and struts, of course you're going to bounce, it's common sense. I have the KYB AGXs and my car is tight. The Sportlines will determine the profile height and the shocks and struts will determine the ride comfort. The original shocks and struts are sh**t compared to an after market setup. Get it right buddy!!

ChoiceCam00

Hi there C Murda, I had your problem when I had the Sportlines installed. The stock shocks and struts will not work with Sportlines. Your car is slammed right now with a 2-2.5 inch drop. The stock setup cannot handled the 2.5 inch difference and your shocks and struts are just bottoming out. Go to http://www.tirerack.com and shop for some good shocks and struts. I hope this helps. Later

May Spin

Sorry.... Have to agree with trackbird..... It's not that the Sportlines are too low, they just don't have enough spring rate to keep them off the bumpstops... Sure a good damper will go along way in controlling roll rates and brake dive, but we're dealing with rates no different than the Prokit, but a hell of alot closer to the stops. A lot of shock valving will be needed to prevent contact with the stops, and that will effect overall comfort IMO.

Scott.

C Murda

iTrader: (24)

ya they are really soft. ive been looking into shocks right now but i also would rather a stiffer set of springs with the same amount of lowering as the sportline kit. DMS? where can i get them and how much lowering do they offer? custom springs???

Carlos01SS

iTrader: (4)

He's got it right mang...

Sportlines are not considered a "performance" spring by folks who know what and how a great handling f-body feels like unfortunately...

And, bottomline, if you're happy with your sportlines & AGX's then that's all that matters right?

I would not suggest sportlines & KYB AGX's to someone who wants a great handling car.

C Murda replacing the springs is not as important as replacing the shocks, but since you feel that it's too soft, then the DMS or the Eibach Prokits or the HR aftermarket springs are just fine, as long as you either match the springs with some Bilstein's that are revalved to match the springs that you get or buy some Koni SA's(Single Adjustable) and adjust the shocks yourself, either way your handling will be great...

Shoot you can keep the factory springs and just switch to either Bilstein HD's or Koni SA's and you'll feel a HUGE difference in your cars cornering ability, it'll still be at factory height though...

There are some things you can do when you use the factory springs like the water hose mod for the rear springs, there are others on this site that have done it and lowered their rear end a bit...I'm not familiar with that mod though.

Good luck!!!

trackbird

iTrader: (4)

Sportlines are lower and softer than the Pro kit (also from Eibach). I forget the rates off the top of my head (I'm sure I can dig them up somewhere). Anyway, as you go lower, you need more spring rate to keep the car off of the ground (it uses the bumpstops, even at stock ride height, but it will use them more as it's lowered and even more when lowered with stock springs). If Eibach thought you needed "X" spring rate at the pro kit height, why would they lower the car even more and use a softer spring in a performance application? They wouldn't.

Sorry, the Sportline kit is an appearance kit. If you like the Sportline look, you buy sportlines, if you want to upgrade handling performance, you buy one of several other springs.

As stated, if you have it and you like it, that's great. But that won't change anything I've stated. That doesn't make it bad for you, I'm just explaining the facts.

C Murda

iTrader: (24)

well i wanna be low and i want a firm solid ride. ive got a tq arm LCAs and panhard bar and waiting on my subframes to get here. anyone know of custome springs i can get and where?

trackbird

iTrader: (4)

You can use the ground control kit to get pretty low (if you insist on doing so), and you can pick suitable rates for that (or at least better rates). I still think these cars work a bit better at a higher ride height (about 26.5" at the fender), but if you insist on being lower, I'd use more spring.

Carlos01SS

iTrader: (4)

I concur as my ride height is @26" front 26-3/8" rears, I have the GC setup with the 500# linear fronts and the 150# progressive rears, and I feel that I should have gotten 600# & 175#, but hey I can always get those later...Either that or firm up my Koni DA's...

trackbird

iTrader: (4)

I'm at 26.5" and running 600's/150's with DA's. It works very well for me and I managed to win the OVR SCCA SM2 championship last year. So, the car seems to work well enough (if I could only learn to drive.....).

Carlos01SS

iTrader: (4)

:hmm: Maybe I should get the 600 fronts and see what happens...

trackbird

iTrader: (4)

At your ride height, I would try 600's (and maybe raise it 1/4" or so). I'm sure it won't be worse, and it very well could be better.

I'm running that with an ST 35mm front bar and a 22mm hollow "Strano" rear bar.

Carlos01SS

iTrader: (4)

:hmm: I just miiiight do that.

C Murda

iTrader: (24)

hmm i forgot to consider ground control......now if i got that kit what springs (height wise) would i want if i want a to be able to adjust to 3" lower than stock...not that im gonna do that just want the adjustability? and for a nice firm ride id go with 600 fronts and 175 rears??

ChoiceCam00

Ok trackbird, my car is already stiff and hard riding with the back adjusted to 4 and the fronts adjusted to 3. What would you suggest for a reasonable price?

C Murda

iTrader: (24)

wait...what from ground control am i actually looking for? coil overs? i was thinking of weight jacks but the ones im thinking of i cant see working on our 4th gen front suspension....i was thinking of the weight jacks that 3rd gens use.....?

trackbird

iTrader: (4)

You had to throw "reasonable price" in there. Since that varies from person to person, I'll put it this way....

I'd switch to the Hotchkiss springs, or even a Pro kit (for a "ready made" spring kit that works well) and change to either a revalved Bilstien or a Koni SA. The lack of ride height and soft (soft-ish?) springs will have you bouncing off of the bumpstops constantly (or at least in contact with them). That will give a hard/rough ride. Also, the KYB shocks are not valved particularly well for our cars. Before anyone gets upset, let me explain why. It appears that KYB took the stock valving and added adjustments for 10%, 20%, etc, from stock. However, we all know that the stock Decarbons are not really anywhere near optimum. They have way, way more compression damping than they need and not nearly enough rebound damping for the job. So, giving us more of a bad thing is not good. Again, if you have those shocks and they work for you and you're happy with them, keep them. For those who are looking for "something else" (like the question I'm answering now), I'd rate shocks as far more important than springs. If the shocks don't work with the springs, it's a bit of a pointless excercise. Now, I know that 400 people will hop in here and tell me that they've used stock shocks with this spring and that spring and it's fine and I'm crazy. Everyone has an opinion. And we don't/won't agree on that one. See any of the "I just installed SA's and it's amazing" threads that have been popping up lately. Don't knock it until you've tried it.

Now, once you get the car a bit higher than the sportlines (step one), I'd place a priority on getting a shock that works with the package. That's the really important part.

Last weekend, we installed Koni SA's on Pimpmaro's car (with H&R springs) and he called me the next day to tell me that he's fallen in love with driving his car all over again. "It's amazing" was one of his comments. It's firm, and controlled, but not stiff for the sake of being stiff (not brutal/punishing). He's thrilled. I don't want to sound like a broken record, but Koni SA's work. Revalved Bilstiens work. Proper shock valving works (Koni's just seem to be the easiest way to get it, which is why I recommend them often).

If you are truly trying to fix a ride problem, shocks are going to be a key player in that.

If you have another combination and like it and are happy with the ride, use it. But to address the question posed above, the answer is "shocks, shocks, shocks, shocks".....and "a bit more ride height and spring rate".

If you insist on being "sportline low", I'd run at least a 600 in lb front spring and very likely a 175 rear (maybe even a 650 on the front). The spring rate will help reduce the tendency to stay almost constantly on the bump stops (reduce the battering effect of hitting the stops constantly), coupled with proper shock valving/damping, it will be much, much better. But, I'd rather see you raise the car a bit, it's far easier to make it better by raising it 1/4 to 5/16".

ChoiceCam00

I knew the Konis are the way to go. The pro circuit use them, that tells you something. About the revalving, I've heard of that but now understand after you've explained it. And, that explains the bouncing that I seemed to think our cars have when upgrading the springs, shocks and struts. My bad, I thought that was the way it is. I do want to raise the car an inch but like the profile so much that I will have to change my way of thinking when I drive. I always like to be at the height of Corvettes but I guess lower isn't better! Performance over lower ride height is the way to go I guess. With my DRs out back, raising the car 1-1.5 inches would make sense. Thanks for the expert advice, If I knew this about the Sportlines, I would have bought the Prokit instead. Later, Kevin.