It seems to be alot of confusion about which spring rates to use on a coilover in front/rear. One guy on the forum with ride problems had received rear 350lbs and front 500 lbs from a vendor.

I have on DRM's recommendation rear 600lbs, front 450lbs. I know it's a very good combination from all races I've been running.

What spring rates do you have ?

It would be greatly appreciated if any of the Supporting Vendors could chime in and tell what they are selling, Breathless, Westcoast corvette .....

:confused: :confused:




[Modified by seanr, 7:30 PM 1/10/2002]

 

Are you sure about your rates Front to Rear?

Because of the distributon of weight in the car, and the engine being in front, and the fact that braking effort is transmitted forward , etc... Most front engined cars get the higher rate springs in the front.

Sorry, I just have never put lighter springs in front and heavier in back on anything. I could see in it a Porsche, but not a Vette.

Just curious.

 

I called DRM again 5 minutes ago to verify my coilover spring rates once more. The rear is 600 lbs and front 450 lbs as I said before.

I got a long education session by DRM/Peter Sikkila about how the suspension is working in the C5, I will just quote a couple of interesting facts.

First, the C5 is a 50/50 weight ratio car so that is one parameter that gives why you have the higher spring rate in the rear.

Second, the angle of the coilover shock in the rear will cause a 'spring rate loss' of about 75lbs on a 600lbs spring so a 600lbs rear spring behaves like a 525lbs spring.

Third, the spring rates is matched to the swaybars you are using. I'm using the GM T1 race sway bars front/rear so the spring rates I have is matched to the T1's. The sway bar is a part of the wheel dynamics moving up/down on the road surface. A car with softer bars such as Hotchkis or the Z51 needs a higher spring rate. But the ratio between the front and rear remains, high in the rear, low in the front.

Forth, the shock valving must be set to match the selected spring rate and swaybar to get a optimal setup.

Fifth, the stock leaf spring rate in the rear is higher than in the front so that is why the coilover spring rate shall be higher in the rear than in the front .

Last, the coilovers sold by Breathless and Westcoast corvettes and some other vendors is a midrange coilover made in the beginning for Pontiac/Camaro class of cars. Please, I'm not pointing finger at anyone using them but you should be aware of the old saying, you get what you pay for. Maybe your high performance car is worth more when upgrading the suspension.


My question remains. What spring rates are you using ??

:seeya




[Modified by seanr, 11:34 PM 1/10/2002]

 

ttt

 

Thanks very much for the information.

I was aware of the 50/50 blanace of the car, but I had just never heard of setting up a coil-over setup this way. Thnaks for the information.

Like they say, you learn something new every day.

 

Glad to see someone knows what they are selling and what to do with it. If you want knowledge deal with an experienced shop if you want oil just go to Costco but don't ask the stockboy which one to buy. Keep up the good work Peter :D


[Modified by John Shiels, 6:02 PM 1/10/2002]

 

Peter is first class and an asset to DRM. My coil over search is over and the vendor will be DRM.

Thanks, Sean and Peter!

 

ttt

Last try to get some input about what spring rates you use with your coilovers. Those of you using coilovers, have you verified that you have correct spring rates/swaybar combo ?

:seeya

 

I'm posting a link to this in BPP's vendor section. I would like to know about the BPP's. Eric

 

It seems like no one knows which spring rates they are using ;)

Because more and more forum members are getting interested in coilovers I just want to add my $0.02 of advice. To save you a lot of headache go with a experienced tuner like DRM, Mallett or LPE to get a correct setup for your car and its intended use. Remember, the spring rate, swaybar type and shock valving must be matched to get the most out of your car and I'm sure your $50K sports car is worth more than a $1300 coilover setup.

:seeya

 

Thanks, Sean. I really appreciate your post and it made clear the real issues that need to be addressed in the coil over conversion.

I think it's interesting to see no response from the vendors offering the low price coil overs.

 

Yes. I even posted a link to this thread on BPP's Forum section. Wonder why no response. Maybe no information. :confused: :conehead Eric