Working out spring rates for coilovers

[Spinbitch]

With wanting to get on with my project again I'm looking to sort out the suspension and get the car on wheels asap.
But I'm not sure how to work out the spring rate that will best suit my car as I'll be running a heavier Saab turbo engine up front, battery in boot, roll cage, etc
Anybody got any suggestions on rates to use on a MK3 Astra hatchback for track and fast road use?

Cheers Chris.

[westyvan1]

i can ask deek for u mate he made some for the van i had and it took a couple of sets to get it right

[Spinbitch]

Cheers mate, if you could that would be great.

[Mieran]

I've been in a mk3 van with saab engine and 500lb springs, still felt soft tbh, would got a bit harder

[Spinbitch]

Ok thats good info mate thanks.

[*BenH*]

If you can weigh the front of the car, you can use that to work out rate. What you need to do is decide what the frequency is that you want in cycles per minute, then using the weight calculate the spring rate. Have a look here Critical Performance Factors in Suspension Set Up for a better explaination. You can then make sure the rear is balanced to the front.

[Spinbitch]

Aye would be indeal to weigh mine unfortunally its still a bare shell with just a roll cage welded in.

[*BenH*]

Just wait till it's a bit more together, springs are easy enough to get off the shelf anyhow. I'm going down this route for mine and will be adding sandbags to the front seats to get it spot on.