924Board.org

Neil924 · Joined: 18 Mar 2003 Posts: 4225 Location: Canada

I'm replacing mine to get a little more height {mine we cut as part of the lowering procedure} and I'm not sure of the specs.

Is there a way to tell my measuring the diameter of the spring and the distance between the rungs?

Also what was the stock spring rate numbers?

Thanks.

RC · Joined: 25 Mar 2007 Posts: 2637 Location: Australia

http://dspace.dial.pipex.com/town/pipexdsl/s/asco96/944t/SuspensionPreparation.htm

http://www.clarks-garage.com/shop-manual/susp-15.htm

http://www.924.org/techsection/technical.htm

Think I read somewhere that the 77NA front coils are identified by 2 red paint marks. Could not find any on mine so expect to be corrected on this.

Roger

Neil924 · Joined: 18 Mar 2003 Posts: 4225 Location: Canada

Neil924 · Joined: 18 Mar 2003 Posts: 4225 Location: Canada

So 140 - 170 is what I will guess is on my car right now.

Thanks Roger.

!tom · Posted: Tue Sep 11, 2007 5:58 am Post subject:

Cutting a spring will change its rate.
_________________
78 924 NA
5-lug

Neil924 · Joined: 18 Mar 2003 Posts: 4225 Location: Canada

!tom · Posted: Tue Sep 11, 2007 7:15 am Post subject:

Cutting the spring will increase the rate because the overall length is shorter. The about the rate is changed depends on the amount cut off, not the fact that you have cut it. Cutting 1/8" off the end of your front springs won't have any practical effect on the rate, but an amount to change the ride height will.

Imagine the spring unwound, and imagine the foce needed to deflect it. I find it easy to visualise springs this way, and it is clear that a shorter spring takes more force to move it the same distance than a longer spring. This is in fact what happens when you coil the spring back up again and stick it on your car.
_________________
78 924 NA
5-lug

Neil924 · Joined: 18 Mar 2003 Posts: 4225 Location: Canada

!tom · Posted: Tue Sep 11, 2007 8:09 am Post subject:

You'll have to figure it out yourself, since I don't know enough information off-hand.

If you change the length of a spring by 10%, the rate of the spring will change by 10%. So, determine the amount of spring cut off relative to the original length of the spring, and this is what your rate changed by.

The same goes for torsion springs as well. . .
_________________
78 924 NA
5-lug