Cascade Crew

QwkTrip · Posted: Wed Jun 29, 2011 6:06 pm Post subject: Spring rates for coil-over setup

Just wondering what you guys have seen people using with coil-over setups? My BMR crossmember didn't come with spring perches and I don't want to spend money to buy them. So I'm going to resurrect the PA Racing coil-over setup I have.

Right now I have AFCO 2-5/8 x 10 inch springs 175 lb/inch. Seems puny. Real puny. Not sure how the heck PA Racing thought that was a good match.

So... what would you guys run with a small block aluminum head engine? That's pretty much equivalent weight to my iron block LSx setup.

rjmcgee · The Hammer Joined: 08 Jan 2004 Posts: 2320

Might not be bad when you consider how much more leverage the spring will have by moving it out. Are the strut towers even stong enough for this?

QwkTrip · Posted: Wed Jun 29, 2011 6:30 pm Post subject:

Wait a minute.... This just seems like a bad design to put all the weight of the vehicle on a top hat mating to the shock tower.

I think I'll be buying the spring perches.

QwkTrip · Posted: Wed Jun 29, 2011 6:31 pm Post subject:

LOL! You beat me to it.

Dewey316 · Posted: Wed Jun 29, 2011 7:11 pm Post subject:

Yeah, i have never like the coil-over design. With the stock design, most of the higher forces are see when the springs rebound their energy, the springs absorb most of the compression forces. With the coil over setup, the upper mount sees a lot more force on the compression action.

That said, 175#-325# would seem to be about range for mounting that far out. It is all about the actual wheel rate, which given the change in motion ratio would mean a pretty soft spring in the coil-over setup.

DBL_TKE · Posted: Fri Jul 01, 2011 6:53 am Post subject:

You would need to reinforce the strut tower in order to cope with the extras stress they're going to deal with. I personally don't like coilovers on the front of our cars due to the fact that it limits you even further with how wide of a wheel/tire you can run up front.