: spring rates on REAR coil-over conversion????



runsfromdacops
02-28-13, 07:15 PM
hey guys i know its been covered to some extant but i cant find any of the therads about it. im trying to track down the spring rates for the REARs that have done the coil overs. i think some guys were doing it with the front springs from a GC kit. but any info would help. im trying to make a set of strange coil-overs work on my V

-alex
thanks for the help guys

OneFast V
02-28-13, 07:28 PM
If you talking about a true coil over in the rear generally 350#-400# would be the preferred rate. if you are taking about just putting in a new spring where the old one was with the addition of an adjustable collar than the spring rate are generally the spring rate of the front +50# i.e. 550f/550r

FuzzyLogic
02-28-13, 07:34 PM
The maximum I recommend for linear springs is 650 in-lbs front and 700 in-lbs rear for a Ground Control-type setup. It's a little uncomfortable for girls, though, so you may want to consider starting at 600 in-lbs front and 650 in-lbs rear. If you have true rear coilovers, you're going to want to drop the rear spring rate by about 100 in-lbs.

runsfromdacops
02-28-13, 07:36 PM
thanks fuzzy.
im talking true coil over IE moving the spring on to the shock

OneFast V
02-28-13, 07:45 PM
thanks fuzzy.
im talking true coil over IE moving the spring on to the shock

If you run 650 front then you should run 350 rear. If you run 700 front then you should run 400 rear.

FuzzyLogic
02-28-13, 08:03 PM
If you run 650 front then you should run 350 rear. If you run 700 front then you should run 400 rear.

I can't find the thread at the moment (at class), but I thought that a lot of CTS-V people were unconvinced that the rear spring rates should be that low. Last I checked, people were ordering 500 and 550 in-lb springs, but I never heard impressions.

runsfromdacops
02-28-13, 08:18 PM
yeah i would think it would be higher. i just want to see what the norm is on the coilover rate so i have a good starting point. im sure ill goo atlest 100lbs over what most do as im going to be drag racing it alot

odla
02-28-13, 09:01 PM
I thought that for drag racing you want the car to squat. So you would want a softer spring?

OneFast V
02-28-13, 09:44 PM
I measured the while rear suspension and did the calculations to tune the car for the proper frequency. I will post that sheet when I get to my computer. If anything drag racing requires softer springs.

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see attached. if you'd like a further explanation i can elaborate.
https://lh4.googleusercontent.com/-WznhLPX-r5E/UTAHny3z_sI/AAAAAAAAAeg/XLcOoy8jkTY/s902/spring+calculations.jpg

JDB
02-28-13, 11:31 PM
If you run 650 front then you should run 350 rear. If you run 700 front then you should run 400 rear.

Sure, if you want an ass dragger for a drag strip car to hook up.

Not good for a road course track car.

550/650 here

OneFast V
02-28-13, 11:59 PM
Sure, if you want an ass dragger for a drag strip car to hook up.

Not good for a road course track car.

550/650 here

You misread. This is exclusively if you are converting the rears to coilovers. If std setup then yes you are correct.

BradCTSV
03-01-13, 02:18 AM
I have the LG true coilovers in the rear and I believe they are in 500 lb range. Fronts in 700 lb. range

etcts-v
03-01-13, 02:32 AM
I've got 600 in the front, 650 in the rear in the stock perch.

OneFast V
03-01-13, 02:33 AM
I have the LG true coilovers in the rear and I believe they are in 500 lb range. Fronts in 700 lb. range
LG motorsports are 700/400

darkman
03-01-13, 07:54 AM
LG motorsports are 700/400

And Angelo Zarra (engineer) recommends the same 700/400 for Anze Suspension's Penske-based true coilovers.

crankedupforit
03-01-13, 12:39 PM
true coilovers.

True coilovers in the rear have a different wheel rate as the inboard config on a stock location spring. Darkman used the magic word "true". KWs and GCs are not true coilovers in the rear so the control arm has much more leverage on the spring thus requiring more rate as Fuzzy has recommended. For true coilovers Angelo's' recommendation make sense.

etcts-v
03-01-13, 03:25 PM
700 seems a little stiff for a daily driver am I incorrect on this assumption? I'm wondering if I should bump to 700/750?

darkman
03-01-13, 03:38 PM
700 seems a little stiff for a daily driver am I incorrect on this assumption? I'm wondering if I should bump to 700/750?

The 700 level is not too stiff for daily driving, IF the shock is set up to control it. In the two cases cited in this thread (Anze's Penske setup and LG Motorsport's setup) the supplier presumably matched the shock to the spring. That does not mean 700 is the right answer for any shock.

etcts-v
03-01-13, 05:03 PM
The 700 level is not too stiff for daily driving, IF the shock is set up to control it. In the two cases cited in this thread (Anze's Penske setup and LG Motorsport's setup) the supplier presumably matched the shock to the spring. That does not mean 700 is the right answer for any shock.

Gotcha, so many variables with setting up the best suspension for your required use! Been reading grips of books on frequency, camber, caster, toe, rebound rates, etc but still a bit foggy..

Junior1
03-01-13, 07:36 PM
900/500 on my Penske setup by Angelo at Anze...

runsfromdacops
03-01-13, 09:37 PM
Dam. 900/500. Sounds stiff. Im thinking about 450 as a rear rate for my car. Keep in mind that the car make 875/860 and is used mostly for roll racing and drag racing. I also can NOT lower the car at all becuse of my charge pipe

JDB
03-11-13, 10:30 PM
You misread. This is exclusively if you are converting the rears to coilovers. If std setup then yes you are correct.

Oops. Sorry. I did miss that.

I wish we had more coilovers options at reasonable $.

runsfromdacops
03-13-13, 01:15 PM
looks like my rears just shipped form strange, i went with 450# rears

nikdsctsv
03-13-13, 11:50 PM
And fronts?

runsfromdacops
03-14-13, 01:29 AM
stock fronts for now. i will be adapting the some satrage fronts in the near future.

OneFast V
03-14-13, 11:52 AM
stock fronts for now. i will be adapting the some satrage fronts in the near future.

Stock fronts with 450# true coilover rears will make for a very sloppy ride. You've essentially doubled the rear wheel rate while leaving the front wheel rate unchanged. The differing Frequencies could cause a lot of issues as far as handling goes.