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My '87 n/a was ordered with the sport suspension package (forget the option code offhand) and has a 25.5mm front and 18mm rear sway bar from the factory. I refreshed all the bushings, added the 968 caster blocks, swapped the original sach shocks for koni adjustables f/r, 200lb Weltmeister springs in the front, and the KLA sway bar brace. Paired with some Bridgestone RE-11's, it handles very well for spirited road/track driving, with a slight bit of oversteer when pushed, but really only when adding/lifting the throttle mid-turn. I think Porsche later moved away from the 18mm rear sway and went to 14mm as a result of some oversteer complaints with this setup. You really cant go wrong with 18mm or 14mm in the rear - the important thing is that you have something there if you want balanced handing. If driving mostly on the street, I would stick to rubber bushings and avoid poly/delrin at all costs - my personal opinion from having experienced both.
I am not looking to "improve" handling on the car at this point, my goal is to get it solid and reliable in stock trim. Given he is a new driver I want to avoid any tendancy toward the car wanting to oversteer, but also do not want it to push like a '57 chevy, so I think a stock setup makes the most sense starting out? With that in mind I am debating now do I find a 21.5mm front bar to swap in and run no rear or maybe put a 14mm rear in offset the larger 25.5mm bar already installed up front but still keep the car balanced toward pushing rather than oversteer? I worry the 25.5 with no rear at all will really make it push?
According to Clarks a 16mm rear sway was standard in 1987 NA. That makes sense because a 25.5 front only would seem to be unbalanced. I think you could put in the 18mm turbo (more available) and it would be fine. You can increase push if needed by running lower tire pressure in the front.
According to Clarks a 16mm rear sway was standard in 1987 NA. That makes sense because a 25.5 front only would seem to be unbalanced. I think you could put in the 18mm turbo (more available) and it would be fine. You can increase push if needed by running lower tire pressure in the front.
I think you mean higher tire pressure in the front for increased push.
According to Clarks a 16mm rear sway was standard in 1987 NA. That makes sense because a 25.5 front only would seem to be unbalanced. I think you could put in the 18mm turbo (more available) and it would be fine. You can increase push if needed by running lower tire pressure in the front.
I believe that was with the M030 option.
Stock was 21.5mm front, and 18mm optional rear the way I read Clarks
I think you mean higher tire pressure in the front for increased push.
No, lower tire pressure in front increase the slip angle of the tire which increases the understeer. 944 factory tire pressures were 36R/29F which was set by Porsche lawyers to promote understeer.
Air pressure is the last, finest tune avenue.
You should adjust under/over steer by mechanical means.
T
Agreed. However a 23mm or 21.5mm front sway with 18mm rear will be close to neutral (under power) with stock springs and torsion bars. Then you can use air pressure to tweak between slight O/s and slight U/s.
If you want understeer for your son in throttle lift scenarios then I would stick with a 20 or 21.5mm front and no rear sway. When he gets use to the car then you can always bolt on the rear sway.
Agreed. However a 23mm or 21.5mm front sway with 18mm rear will be close to neutral (under power) with stock springs and torsion bars. Then you can use air pressure to tweak between slight O/s and slight U/s.
If you want understeer for your son in throttle lift scenarios then I would stick with a 20 or 21.5mm front and no rear sway. When he gets use to the car then you can always bolt on the rear sway.
Lol, could be, but if you have a seat of the pants ability to notice 2 lbs of air handling balance difference on street tires on city/count road surfaces, you should be on the race track....
Agreed. However a 23mm or 21.5mm front sway with 18mm rear will be close to neutral (under power) with stock springs and torsion bars. Then you can use air pressure to tweak between slight O/s and slight U/s.
If you want understeer for your son in throttle lift scenarios then I would stick with a 20 or 21.5mm front and no rear sway. When he gets use to the car then you can always bolt on the rear sway.
I agree, but the car we bought has a 25.5 up front and nothing in the rear, so I am trying to figure out what to put in the tail. I think 25.5 up front and nothing in the back is likely a bit too much understeer?
Lol, could be, but if you have a seat of the pants ability to notice 2 lbs of air handling balance difference on street tires on city/count road surfaces, you should be on the race track....
T
I can surely tell the difference with 7psi (factory specs) between front and rear. 29/36 versus 33/33. I'll bet you could too.
I agree, but the car we bought has a 25.5 up front and nothing in the rear, so I am trying to figure out what to put in the tail. I think 25.5 up front and nothing in the back is likely a bit too much understeer?
Yes assuming the rear torsion bars are stock. Do you know for sure if this is the case?
Take it to a parking lot one early sunday morning and drive it in a tight circle and see which end breaks loose first....
No, lower tire pressure in front increase the slip angle of the tire which increases the understeer. 944 factory tire pressures were 36R/29F which was set by Porsche lawyers to promote understeer.
Ah i see what you mean, lower tire pressures in the front than in the rear, that may be true.
I took your comment to mean, reducing front tire pressure increases understeer...which is incorrect.
They do cause failures with big bars. I’ve torn 4 with a 30mm front bar and the braces. As soon as I took the braces off they started to live. I lost a set of Delrin inserts to one of those failures too.
Originally Posted by mj951
The 45 deg brace for the inner sway bar mount will not cause failure. Many here have them, I've been running the setup described on both street and track for ten years without issue.
Use a torque wrench for tightening, you don't want to over tighten the chassis mounts and strip a thread. Also have the vehicle resting on its tires when tightening the suspension.
Ball joints are also worth checking when you start taking the front suspension apart.
Good luck, the fun begins!
06-14-2018, 09:34 PM
