s85b50

Stock springs look like they have linear spring rates (no diameter changes)..considering at Hypercoil/Swift/Eibach.
I know that Koni Yellows have adjustable rebound so the spring choice isn't too vast, but I am looking to decrease roll in 80mph sweepers.
Basically looking for M030 suspension setup but with cheaper alternatives. Any recommendations?

MAGK944

You’ll need coilover struts to fit Hyperco, Swift or Eibach springs, they don’t make springs for the stock struts, afaik nobody does. While increasing the spring rate will help somewhat on roll, you will be better off upgrading your sway bars. Last time I looked 944/951 M030 sways were not to expensive and would be a straight swap for your current sways.

s85b50

So you are suggesting M030 springs(??? lbs/in) or stock springs (160 lbs/in for '83) and adjust rebound with Koni in the front?
Yes Sway bars will be upgraded. Thinking of 23/14mm or 26/16mm

MAGK944

I was suggesting 944/951 M030 f&r sways as they are cheap, plentiful and an upgrade for stock 1983 944 sways. M030 springs or any aftermarket springs like Hyperco won’t fit your struts. Like I said, you need coilover struts and then you will have an almost infinite choice of spring rates.

s85b50

Oh I wasn't clear. My front struts are toast and I need to replace them anyway, so I was looking into upgrading other parts of the suspension. I will upgrade the sway bars as well.
So even the M030 springs will not fit the stock strut housings? That's new info.

T&T Racing

Is this a track car? What is the diameter of the rear torsion bars? I have testing suspension data for my '83 944 on suspension setups, what does not work, what is better, and what is the best. Lots of self-inflicted bad setups until I got it right. So my experience is data and test driven.

M030 front and 3 position adjustable rear sway bars are the best approach. The diameter of the sway bars need to be with the effective spring rates of the front springs and the rear torsion bars. Spring Rate is not effective spring rate.

The rule of thumb is the front effective spring rate does not exceed the rear torsion bar effective spring rate.

So it is important to know the rear torsion bar diameter to start the process.

The Koni shocks are on the stiffer side for non adjustable compression and rebound is adjustable but stiff for all the effective spring rate combos.

MAGK944

The Porsche 944 M030 suspension comprises of coilover struts with height adjustable spring perches and takes a different spring to the stock 944 struts.

If your struts are toast and you want to up the spring rate you have two choices:

get a set of coilover struts from Ground Control, KW, etc; or

convert your current factory struts to coilovers using a sleeve and fit Koni or Bilstein inserts.

Both these options will allow you to choose any spring you desire.

s85b50

Rear torsion bar is stock so likely 23.5mm. I know 14mm rear works because that was the factory option, along with 23mm front.
I am trying to figure out if a larger diameter front sway bar would work with Koni Yellow & stock non M030 springs.
If compression is on the stiffer side that's exactly what I am looking for but I would want a little more gradual rebound. The car is mainly for street but looking to autoX/light track in the near future. The car will be installed with LR ultra mounts as well.
I should also add that I have Bilstein HD rear shocks. Looks like they are valved 235R/119C.

Handling wise I prefer slight oversteer as I think these underpowered NAs could greatly benefit from faster turn in.

MAGK944

Its a bit confusing trying to figure out what you want to achieve. If you are running a 23mm front sway then that is already an upgrade from the stock bar on a 1983 car. Your (Koni yellow) inserts are used to control the springs not the sway bars and you generally match the sways to the springs not the inserts or dampers. On our cars when you start to get above a 200 pound front spring rate the 968 M030 front sways work well but I see no advantage in increasing the sway bars rate from you current upgrade if you are still going to run stock 160 pound front springs.

Also why are you fitting Lindsey Ultra Mounts, they are far inferior to stock hydraulic mounts, they will cause vibration and your fuel rail and oil pick up tube will be stressed.

s85b50

My stock sway bar is l20mm, it does not have a rear sway bar. That's why I mentioned 23/14mm or 26/16mm as possible options.

MAGK944

Ah ok, both of those options will improve roll as they are an upgrade on what you currently have and will work well with your stock springs. They are also quite cheap and easy to find used. However, if you feel you need stiffer springs you will have to fit coilovers at the front with about 200-220 springs and then maybe go up to the 30/19mm sway bars from the 968 M030 cars. This is much more expensive but you will definitely feel the car handling better. Anything more than about 220 front spring rate and you will also need to upgrade the rear torsion bars or remove them and fit coilovers back there too.

If it was my car I would fit the coilover sleeves onto the stock struts, Koni inserts, 220 front springs and 30/19mm sways. Then lower the rear to the lowest on the eccentric and level up the front or even a slight forward rake using the front coilover adjustment. It's a proven old school setting for these cars and likely your cheapest and easiest option.

T&T Racing

Contact Jason at Paragon Products Porsche. He can help.

voodu3

X2 on reaching out to Jason at paragon. I’m doing the same thing on my ‘86 NA. He’s been a huge help. I’ve just got to save up for the sways now.

T&T Racing

Lindsey Racing has M030 sway bar mounting bracket for early 944 front lower control arms. If OP wants slight oversteer, then I believe 26.8mm or 25.5mm front sway bar will work with 19mm rear sway bar. The front sway bars are available used from dcAuto Porsche dismantlers

MAGK944

Yep +1 what I suggested earlier, the 25.5mm M030 option fronts are a cheap and effective upgrade for the early cars.