johntorg

I just removed my 30 MM torsion bars and replaced them with bilstein coilovers with 550lb 8 inch springs. I did this to gain adjustability (also to lower the rear ride height) without reindexing the torsion bars.

To my suprise the car still sits at the same or a slightly higher rear ride height, even with the eccentrics almost maxed out and the coilovers in the lowest position.

One thing I did notice is that the springs are under tension, even in the lowest setting on the lower spring perch.

Is this normal? I could go to 7 inch springs, which would definitely lower the car, but I am worried about the springs bottoming out.

I would appreciate any input, particularly from 944 racers using coilovers in the rear. Input on front and rear ride height (and how it was measured) for a 944 race car would also be interesting.

johntorg

The shocks are the same as these, currently for sale on ebay. http://cgi.ebay.com/ebaymotors/*-2-P...QQcmdZViewItem

The springs also look like they are under tension with the perch almost completely lowered.

Larry Herman

We run 7" springs with 650 lb springs in our 951. It sits exactly right for what we wanted. I can take pics later if you need them.

North Coast Cab

I run 6" x 2.25" springs on my rear.

johntorg

Thanks, I really appreciate the answers. I will go to smaller springs. BTW the problem is that my new car has aluminum rear control arms and the old one had steel, which locates the bottom of the shock considerably lower. The lowermount also looks a lot stronger on the steel arms.

smlporsche

I'm running 8" (600#) springs with my Leda's and have no problem setting my car at the height I want. It sounds like it may be your control arms...

johntorg

Spent some time at Roebling yesterday measuring ride height on 4 or 5 944s. I will go with smaller springs and look for 23.5 inches rear ride height with 225/45/15 Hoosiers. Any opinions on 6" vs 7" springs. I will go with 700lb springs and was wondering if I could bottom out the 6" springs.

spoolin51

I am having a similiar yet different problem. We just deleted the torsion bars and have 800# springs in the rear. WHen we lowered the car to the ground, the rear end was basically sitting on the tires. Something is definitely not right.
Any input greatly appreciated.

johntorg

What is the length of your springs? Steel or aluminum control arms?. I suspect if you have short, 6 or 7 inch springs and steel control arms you would have this problem. Also where are the height eccentrics set?

Van

The height eccentrics have absolutely no effect once the torsion bars are removed. All they do is rotate the spring plate cap (which has the splines that engage one end of the torsion bar).

Your only ride height adjustment is the threaded collars on the shocks.

You need shorter springs.

johntorg

Thanks, I hadn't thought of that. Anyone have 6 or 7 inch 2.5X600 to 700 lb springs?

johntorg

I just wanted to check my calculation for various front to rear spring ratios before I buy my new rear springs. I divided the front spring rate by .65 to get the following results:

Front Rear
450 692
500 769
550 846

Given what's available that would corrspond to 700, 750 and 850lb springs

Van

Your division is accurate, but the pairing is more dependent on car weight, driver preference, etc. Are you looking to have the same wheel rate as your 30mm torsion bars yielded? Were they solid or hollow?

johntorg

Car weight is 2800 minimum, since its a 2.7L. I found the car was too soft in the rear with the 30MM T-bars. I am really just looking for a starting point with equal effective rates front and rear. I will check today to see what my front spring rate is (bad memory), but its somewhere between 450 and 550. What is the effective rate of solid 30mm bars? I am not experienced enough to have a driver preference. Just trying for a good basic setup.

Van

A 30mm solid torsion bar will give you a wheel rate of about 329 lbs/in. An 825 lb spring will give you about 327 lbs/in. You'll find that people run a whole range of springs - it's hard to say that one setup is "better" than another. One of the best things to do is to get a few springs (they're not too much, and easy to change) and see what you like best.

FYI, a 550 lb spring in the rear will give you a wheel rate of about 218 lbs/in.

On my car, the front weighs about 250 lbs more than the rear - so I have to take that into account with spring calculations. If the car had a true 50-50% weight distribution, I'd have more weight on the rear and less on the front. So I'd then use less front spring and more rear spring.