Front and rear spring rates for coil overs.

chrisp · 01-03-2003, 12:26 PM

I am wondering what spring rates some of you coil over converts are using. I have a an '83 SC an anm looking for recommendations for spring rates and for what type of driving you are doing. I know the deal aboput reinforcing the chassis. I guess mainly I am looking for springs front, and springs rear. Thanks for the help.

TimT · 01-03-2003, 12:30 PM

I have #350 front #550 rear in a lightweight early 911 track car

chrisp · 01-03-2003, 01:13 PM

Okay I'll reply to my own post because I have another, related, question. How do spring rates for coilovers relate to spring rates for torsion bars? I am familiar with the torsion bar rate calculators but is there a way to say that torsion bar of "x" rate should have a coilover spring of "y" rate to get the same effect at the wheel? I should have asked this in my first question but it didn't hit me until now. Maybe if some of you can comment on what t-bar you had and what spring rate you went to and how they compared that would be helpful (if I can't figure how to relate the two to each other mathematically).

Jack Olsen · 01-03-2003, 02:02 PM

Is anyone here familiar with using an 'active tender spring' in conjunction with a conventional spring in the front? I'm looking to see how to calculate the appropriate front spring rate if I'm using two springs. Do I just add them up?

TimT · 01-03-2003, 02:18 PM

look here for torsion bar vs coil over comparisons.

Jack are you talking about those tender spring that just hold the springs on the perches when you jack the car up? Or are you talking about having 2 active springs per wheel?

Those little spring tenders can be discounted from spring rate summations.

If you have 2 linear rate springs the weaker spring will compress to a point ( coil bind) then the stronger spring will take the load, so the effective spring rate will be the rate of the stronger spring, not a summation of both spring rates.

You can get dual spring set ups, with one progressive rate spring,and one linear rate spring. With this set up the progressive spring controls the ride during "normal" driving, allowing a nice comfy ride, when the urge hits to do a few laps the progressive spring will give way to the linear spring.

Truechoice can help figure out spring combinations. I think just some properly slected springs would be fine instead of complicating things with combining progressive and linear springs..