V2Rocket

Pretty soon I'm going to be supercharging my 944. I have a bunch of mods planned out and my goal is 200RWHP. Currently the car makes about 130-140 RWHP.

I want to upgrade the rear suspension to handle this extra power. As some of you may know the 944 has a torsion bar rear suspension. I hope to eventually get some coilovers to replace that.

This car is running the stock suspension, 125 lb/in up front and IIRC 125lb/in in the rear as well.

This car is a daily driver, so I don't want something stiff enough to knock loose a kidney when I hit a pothole. What I want is to keep the car from squatting whenever I let off the gas/hit the clutch.

TIA

V2Rocket

bumpshizzle

Jim Clark

Go to Performance Products and get the 250lb upgrade for a road car. It's going to be bumpy but if you want stability than you need to add rigidity

Lemming

Hmm, I currently have 450's in the rear and I the car still squats a bit. Going to 600 this weekend, that should help some. Not sure I would want to use my car on the street though.

smlporsche

I'm with Tim.
I have 450's as well and it would be too rough for the road. Going with 575's this winter...

lowside67

One thing that is often ignored is that shocks have a huge effect on how cars ride. A car with shocks correctly valved for 450lb springs can be more comfortable than a car with 250lb springs but garbage shocks. I would look at the whole package - if you upgrade your suspension with an eye towards making it all work together you might find that a sizable upgrade is still very livable on a daily basis.

Lemming

600 worked well for the one weekend that I've run them

tangible

you must look at your entire setup, front AND rear, not just rear and not just springs. springs alone will NOT work for what you're trying to achieve.

rear end squat on launch at a minimum needs:
springs in the rear (to put the power to the contact patch, not the chassis)
front shock rebound valving (they have to limit the rise)
to properly resist the effects of torque thrust on the chassis.

and of course, the shock/spring combinations have to be in synch front/rear.

too stiff in the rear relative to the front and you 'pogo' the front end since the rear pickups become a mechanical fulcrum point. your problem is worse!

also ignored many times is that the helper springs utilized can also have a major impact, assuming your setup uses these. you may in fact not be even getting into the main springs if the helpers aren't right.

there are formulas, but without knowing your current setup, calculated roll center, and dyno'd torque increase, anyone commenting here will be guessing.
contrary to popular blogs, there are no shortcuts. every car is different.

get a good local suspension guy and work with him.
their usual deal is they'll sell you a setup after evaluating your car, and then adjust whatever it takes to get it working as you drive into it for no additional charge.

if he won't do it that way, he's just selling you bits and you're still on your own.
good luck!