944 Suspension Refresh Phase 1

[ruffyz]

I recently purchased Paul's cut and gut front suspension and koni rear coil over kit.

The parts:
40091
40088

Being used parts I decided to go ahead and do a simple install without removing the torsion bar just to make sure everything will bolt up.

Everything bolts up!
40090
40089

The fronts are 350 lbs which I matched to the stock 23.5 mm torsion bar by using 250 lbs springs with the rear coil over kit (thanks Greg!). This gives 267 lb effective in the back according to http://garage.ideola.com/top-DL-SpringRates.html.

I tried matching the pre-exsiting ride height as measured from the ground to the fender through the center of the wheel. This turned out to be a problem. The front of the car is now lower by about an inch and the rear is now higher by about an inch. I've maxed out the perches for both the front and the back so really the adjustable ride height kit isn't doing me too much good right now. What did I do wrong? Are the springs just too short? Both sets of springs appear to be about 8 inches.

I'll post more results once I do proper ride height measurement according to the manual and tweak the rear eccentric bolt, but in the meantime do any 944 suspension gurus want to chime in?

[ausgeflippt951]

Good to see you're diving in. You will need to modify the ride height afterwards. If you think about it, you're increasing the spring rate but not changing the curb weight -- meaning the amount the suspension deflects will be less for a given amount of load.

Your front struts' spring perches are likely adjusted overmuch to compensate for this but unfortunately this range of adjustment isn't possible for the rears, requiring you to also use the eccentric to help compensate.


One thing to note: be sure to bounce/roll the suspension in between any changes to enable it to settle better. What at first appears to be 1" difference could turn out to be only 5/8".

[Potomac-Greg]

As Colin says, rear eccentric needs to be fully lowered so you will be bringing the rear coilovers into play. Using torsion bar plus coilover is complex, but you should be able to get it to work. You're basically using two independent spring systems to handle the rear.

The reason you have those springs is because I eventually decided to go "legit" and pull out the torsion bars out, and swap much stiffer springs.

[Dougs951]

If you can get access to a lift it makes adjusting the rear essentric a lot easier.

Also air tools help.

For reference the I will be running 700lb springs on the rear of my 951 with no torsion bars.

[Dimi 944]

Nice upgrade! I would get rid of the torsion bars and run 500# and up springs at the rear if it is a dedicated track car. Ride height adjustability becomes extremely easier that way. I can dig out my write up how to remove the torsion bars without dropping the rear end and without drilling your lower quarter panels if you are interested going that route.

[ruffyz]

I'd love to not have to drop the rear end to remove the torsion cars, but my understanding is that I'd have to drop it replace the guaranteed to be worn out torsion bar bushings.

[Dimi 944]

You do not have to replace these bushings if you are not using torsion bars. I would recommend replacing the spring plate bushings when removing the torsion bars though.

[hobiecat]

I think that's what he meant.

If you're just going to remove the t-bars entirely, definitely no need to completely drop the whole assembly,
but getting the torsion bars out requires some effort - and the quarter panel gets in the way. So...either you loosen
things up so you can tilt the carrier enough to slide them out, or like Dimi did, you cut a hole in the quarter panel.

You still have to disassemble a lot to get the spring plates off...then remove the rubber
bushings, then replace with something other than rubber.

You could go this route - but it's $$$
http://www.elephantracing.com/suspension/bushings/944bushings.htm

Have fun!!

[Dimi 944]

I want to clarify that when I did mine I did not drop the rear end and did not drill the quarter panels. I did tilt each end and this was enough to pull out the spring plates and torsion bars.