this is for a 931, probably very similar to the early 944. (also manual rack)
I just had my front end aligned after replacing the control arm bushings with poly, and the firmer VW fox strut mount rubber. As for the rest: 951 26.8mm front sway, 200lbs front spring with koni sports. rear: stock torsion and Old sachs shocks. 968 3way rear bar on softest position. car is lowered about 1" Wheels are 7&8 D90's with Conti DWS 205/50 front and 20Y/o Sumitomo HTR+ 225 rear (they still seem ok)

When I took it to be aligned they took a little longer and said it was a bit of a pain, I gave them some "performance settings" I found on one of the forums, but they said the best they could do was OE specs. Steering actually felt heavier after the alignment. which I didnt like as much.

I finally got to go up some mountain roads for its first real test.
The steering is quite stable, seems to have a little bit of understeer if pushed on the back side of a turn. I didn't push it very hard, but was "spririted". Theres a little more body roll than I was hoping with the larger sway bars.

(previously, I took the car to a shop where they didn't align it but checked the alignment and gave me a print out of the settings. and went home and made some adjustments, I was able to make the steering "quicker"......dont remember what I did, but I liked that, except it was not as stable. )

So what can be improved/changed?

My plans are to put 17" wheels with 225 and 245 Pilot Sport All season 4, 300lbs front coil over and 475 rear coilover/koni (T bar delete and Poly bronze).

 

thicker front sway bar, higher rate front springs, narrower front wheel = understeer (a lot)
change in Caster would most likely be the change that caused easier/harder steering with a resulting change in heaviness of the steering

if you change to 17" wheels from 15" you'll have a noticeable difference in ride and handling (worse in my opinion)

 

What are your goals?
1. 17" vs 15" wheels affects the acceleration negatively, using a lower gear for same engine rpm, screws up the speedometer reading falsely indicating slower speed leading to more speeding tickets, probably lowers mpg. The suspension has a higher effective spring rate.
2. All square is the best setup. Wide rear tires vs narrower front tires caused understeer.
3. With current setup, making the rear sway bar stiffer reduces understeer.
4. Making the
300lbs front coil over and 475 rear coilover/koni (T bar delete and Poly bronze) is a good balance but expensive and maybe not possible without alot of modifications. Does the 931 have steel rear trailing arms? If so, difficult and maybe impossible to do T bar delete, easier and doable with 951 or late 944 aluminum trailing arms. Then need the longer length rear half shafts. Need a special bolt for aluminum lower control available from Paragon Porsche.

 

If, as you state, want a car that handles well on mountain roads in CO (rough and frost heaved I assume), I would stop right where you are with the stiffness of the suspension. Sure, track dedicated cars run some (IMHO) ridiculous spring rates. This only works because the tracks are smooth and the consequences of going off the track does not typically try and kill you like a typical mountain road will. You need suspension compliance to allow the car to be able to handle those bumpy mountain roads.

As far as I can tell, you added stiffness at the front but stayed stock at the rear. Not a good plan and along with the narrower tires up front, you are of course going to get understeer, as you are causing more cornering weight transfer to the front end, onto a lesser tire contact patch.

Lowering the car also does wierd things with the supension geometry, like adding bump steer. Again, not what you need on uneven road surfaces. Also, withhold judgement until you replace all the 40 year old suspension rubber, front and rear. A Porsche with the suspension rebuilt to stock configuraiton with new suspension bushings and shocks will handle very well. There is no "secret sauce" that they left off the table, for a street car.

Finally, if you got the car aligned, you should have a printout of how they left it, which you should post.

 

totally agree, Joe hit it on the money

 

I already have the coilovers, and the bushings.
D90's are 16", Would be keeping the same rolling diameter with the Pilot sports (which im debating weather to go with the 4S or the all season 4), so 225/45/17 and 245/40/17, will be comparable to stock diameters, right now my speedo reads high actually
Dont think I can go any wider on the fronts.
Im hoping the lower profile tires will give less roll over.

roads in CO aren't too bad, im not concerned with ride quality, and no frost, things are pretty dry here, even after it snows. (but I have a set of Pilot Alpins for that)

Ill have to find the print out.

 

heres the report

 

Thanks for the printout. The most obvious thing is that your "before" toe numbers were way off. I'm assuming a postive number is toe in. The as left numbers are reasonable for a street car. Some folks try a little toe out for track cars. It supposedly makes the car turn in better but has adverse affects for straight line running. It is easy enough to experiment with. You can just try turning each threaded adjuster on the steering arm an equal amount of rotation on both sides or actually set up string lines to check where you are at. Put it back the same amount of terms if you don't like it. BTW in theory, the slight toe in becomes straight ahead when you are running down the road and the wheel bearing clearance is taken up.
Before and after caster are/were within spec. Caster affects the heavyness of the steering but as noted yours are within spec.
Before and after camber is a nominal negative value, which is also fine for street driving. Competition tires will provide a lateral camber thrust when set at values of -2 to -4 degrees. This requires modification to the strut towers, such as adjustable aftermarket camber plates. I would not suggest running these agressive camber values on the street.
FWIW I ran a square setup of 225 tires on my 85 944 track car, with a manual rack. I never felt that the steering was heavy. I got the manual rack from The Machine Shop, located near you.
Remember, the main thing is if you make changes at one end of the car, you have to make changes at the other end, to keep the car balanced.
Finally, I once tried 18" tires/wheels from my Cayman on my 944 once. They fit, barely, but as Tom has pointed out, their inertia characteristics were not favorable.

https://newhillgarage.com/2017/05/20...he-suspension/

 

Youre going to benefit a lot more with some negative camber front/rear (but how much depends on whether the car is mainly for street or track or both). This will greatly increase turn-in response and increase the tires contact patch on hard corners, the trade-off is that it will wear the inside of the tires faster if you do lots of highway driving.

Personally I am running around -2 degrees front and -2.5 rear (mainly because its at its maximum) and I am not using camber plates or offset bolts - this is all with factory adjustment albeit the car is lowered approx 1.5-2".

The rear toe and camber is difficult to adjust on these cars because of the rear trailing arm/spring plate design requires both to be adjusted together and requires a special tool (at least on the 944s). This may be why it took them longer.

Also, always ask the shop (or find one) if they will do alignment specs per your requested settings. If they refuse or say they will only do factory, take it somewhere else (unless you want factory). I have found the smaller local shops will be most willing to do this whereas the brand name places and dealerships are most unwilling to do this.

 

As soon as you said you said you did your own adjustments for better turn in it made me think you changed your toe settings. As mentioned toe settings affect turn in and stability at speed. I'm no expert but I've heard toe out also helps trailers stay more stable at speed.

You have a nearly identical set up to what i had in my '86 944 several years ago with a few exceptions: Koni sports adjustable shocks front and rear, 200 lb lowering springs, standard 944 torsion bars (24mm?), triangulated 26.8 mm front sway bar, 18mm rear sway bar. At the time my '86 was still early offset and I had 16x7 and 16x8 fuchs with 225/50/R16 and 245/45/R16 tyres. New rubber bushings in the front , etc, etc. My camber was between -2 and -2.5 degrees as walfreyydo says. It was an excellent set up for fast open road driving and the odd track day. I think some differences affecting you is the staggered setup and the 19mm rear sway even on the softest setting might be inducing more understeer as suggested. Im not sure what size the torsion bars are in a 931 but i assume its similar to the early 944 which i think is softer than a late 944. The 19mm rear sway is paired with a 30 mm front sway by Porsche on the Turbo S which had optional 17x7.5 and 17x9 wheels with 225/50/R17 and 255/45/R17 tyres.

My current set up is similar but late offset modified 944S2/968 suspension- 200 lb lowered springs, worn bilsteins front and rear, new front and rear suspension bushings, triangulated 26.8mm front sway bar but rear sway is now a 16 mm, rear torsion bars are stock 968 @ 25.5mm. I also now have a strut brace and a control arm brace. My wheels and tyres are 17x8 and 17x9 with 225/50/R17 and 245/45/R17 Michellin PS4S tyres. I wanted 255/45/R17 to maintain the same rolling diameter as the stock wheels but couldn't get them. Again a good setup but i need to replace the front and rear shocks. The tyres are fantastic!

I also agree about the special tool for the rear suspension. I suspect because the shop you used didn't have it or weren't aware they needed it and they got frustrated and stayed with OE spec. I try to find a VW specialist who has torsion bar experience to do my alignments as they have the experience and the tool.

 

I actually do have the rear alignment tool, but told him not to worry about the rear, I just wanted the front straight so I can drive it. Plus I got the 3yr adjustment so I can bring it back any time, or to other locations, which I will do once I swap to coil overs.