Spring rates Stock, H&R, PSS9

[hotrod]

What are the stock 996tt spring rates F & R? What is the highest reasonable rates for street driving? Do the best selling kits come with reasonable rates? I put a set of coilovers on my 996tt with Eibach 800lb rears and 700lb fronts. This is not the answer. Bilstein folks told me I can go 25% lower spring rate and still have the shocks work OK. My feeling now is that 600 and 500 may not be the answer and I don't want to spend the money to try them if it doesn't make sense. Can someone advise?

[PyroKerry]

I can tell you what I have done on my 996TT, but it's not with PSS9 dampers. I have 700# springs in the rear and 500# in the front. The dampers are JRZ Clubsport RS set to 4 for compression and 7 for rebound. Ride height is about 1.25" lower than stock, as the JRZ can handle that. When I bought it, the previous owner had stock shocks and H&R Sport Springs (#29385) lowering springs, so the ride height hasn't changed, but the suspension is radically different.

Your question is, what is acceptable for the street. Most people would say that the H&R lowering setup the first owner had on my car would not be too stiff for the street. I think most would say that the springs I have on now would give a much stiffer ride for the street. But it's difficult for me to say which is the more comfortable ride, because they are so different. I can say I would not like any stiffer springs. Midwest Eurosport in the Chicago area installed my suspension and they talked with JRZ about the spring rates for my (mostly) street setup. They felt 700#/500# was as stiff as I'd want, and they wanted to keep a 200# difference between front and rear.

Problem is, I don't know how those spring rates would feel on your car with PSS9's. It is my daily driver as well as autocross and DE car and I love how this setup handles. It's certainly stiff but I wouldn't change anything.

[hotrod]

I can tell you what I have done on my 996TT, but it's not with PSS9 dampers. I have 700# springs in the rear and 500# in the front. The dampers are JRZ Clubsport RS set to 4 for compression and 7 for rebound. Ride height is about 1.25" lower than stock, as the JRZ can handle that. When I bought it, the previous owner had stock shocks and H&R Sport Springs (#29385) lowering springs, so the ride height hasn't changed, but the suspension is radically different.

Your question is, what is acceptable for the street. Most people would say that the H&R lowering setup the first owner had on my car would not be too stiff for the street. I think most would say that the springs I have on now would give a much stiffer ride for the street. But it's difficult for me to say which is the more comfortable ride, because they are so different. I can say I would not like any stiffer springs. Midwest Eurosport in the Chicago area installed my suspension and they talked with JRZ about the spring rates for my (mostly) street setup. They felt 700#/500# was as stiff as I'd want, and they wanted to keep a 200# difference between front and rear.

Problem is, I don't know how those spring rates would feel on your car with PSS9's. It is my daily driver as well as autocross and DE car and I love how this setup handles. It's certainly stiff but I wouldn't change anything.

Thanks,

I thought the F to R difference should be 100lbs in general. Do you experience oversteer in your setup? Maybe this is how you like your car setup-to oversteer I mean. Do you know what the stock spring rate is? Do you know what the H & R spring rates were? Did you think they felt a lot different than your current setup?

Thanks for taking the time to help me out.

[PyroKerry]

No problem, Hotrod. I'll give out free advice anytime! But you should know this is from someone who has very little knowledge on the subject. From what I've learned, we're in good company on that score.

I've read of people using 100# to 200# differential, and I believe 150# to 200# is more common. I haven't been able to find out what the stock spring rate is, nor the H&R. That H&R 29385 is a progressive spring so it would be tough to compare numbers. My current setup is certainly a lot stiffer than stock, but I don't think it feels much worse than the combination of the stock shocks and the H&Rs. Very small bumps were softer, but it didn't take much of a seam or road divot to make that setup harsh. My new setup feels very different compared to my old '00 C4 with the RoW M030 suspension, which is the only other suspension I've had experience with. A bit stiffer for sure, but what I really notice is that the current setup feels a lot more over sprung, which I like.

I don't think this setup increases oversteer; that wasn't the intention. I do a lot of autocross and if I drive stupidly I can still plow (understeer) with the best of them.

It all comes down to what you think is too stiff or too soft for the street. Nobody would call my setup a marshmallow ride for the street, but it's personal opinion as to whether it's too harsh. I can say that spending money on top quality shocks like JRZ or Moton is money well spent.