Why is my front suspension so stiff?
 

First, I would like to thank all the contributors to this site for their wealth of knowledge that helped me through many of tasks. After a long and expensive restoration of my 80SC I have a few questions about the feel of the front end. It has this feeling of not being planted, floaty and takes bumps hard. It’s like the nose wants to rise up.
Very hard to describe.
Current setup:
New OEM A-arms (All rubber)
New Turbo Tie rods
Replaced sway bar bushings
New Bilsteins - can’t remember if they are HD or Sports (one of the many, many receipts I had to hide from the wife and now can’t find)
New stock 19mm front Torsion bars
New wheel bearings
Corner balanced at Dougherty’s in West Chester, PA (total weight 2583lbs 33%front 66%rear)
Lowered to 25.25 front 24.75 rear
New Michelin Pilot exalto on restored Fuchs (Al Reed sweeet!) Front 205/55/16 @ 24lbs rear 225/50/16 @ 30lbs
Note: I asked the tech that did my corner balance if bump steer would be an issue. So while the car was up on the load cells he sat on the front end, looked at the computer and said no it was not a problem. Bump steer kit was not added.
Lack of weight? I am running without a spare tire and all AC components have been removed from the car.
If I put pressure on the front bumper and try to bounce the front end the suspension does not move very much. Should it be so stiff? I’ve driven the car 800 miles with this setup.
Thanks in advance brothers.
http://forums.pelicanparts.com/uploa...1205034983.jpg

Alignment settings?

Are your shocks adjustable?

Running a car that low with stock torsion bars can lead to hitting the bump-stops.

Since you have Bilsteins, you can get the spindles raised, which will restore some lost suspension travel. Another trick is to cut one segment off the bump rubber, which on a Bilstein strut, is inside the strut housing. The insert must be removed to get to them.

Hi and welcome to PP. Since 911's have torsion bars for springs, bouncing the car on the bumper is always going to feel stiff. The torsion bars actually twist under load and bouncing the bumper is not going to twist them much if at all.

If you have your corner balance weight numbers, post them as well. How old/new are the tires and what type and rating are they? Could be the rubber if your cars balance checks out.

Herms911,

While we're chatting about your car - are you running a front spoiler to go along with your rear turbo spoiler?

It doesn't look like you are. If not, that could be part of your 'floaty' problem.

I agree with Tyson - your front ride height is quite a bit below stock, and you'll get into the bump stops very frequently that way.

Also, I believe the 80's SC still had the higher ride height for the US cars. There may be some big, fat steel washer in the strut to space the bump stops down for the higher front ride height - those need to come out if they are still in there. I haven't ever seen or removed one, but Bruce Anderson's performance book mentions them.

I think it's what Tony suggested. Torsion bar suspensions are always stiff when you bounce the bumper even with old or worn shocks

Thanks Men for all your input
That 33%/66% was a before reading. After appears to be 36/63
The final weight numbers are: see attach
http://forums.pelicanparts.com/uploa...1205074652.jpg
I don't have the specifics of the alignment other than weight.
I just ordered a lower chin spoiler valance.
Is a different front shock selection worth looking into? Re-valving?
Thanks for spending time on me.

Well, hitting the bump stops is going to give the skittery bumpy feel to the car, and the dampers are not set for that stiff of a spring, LOL.

So, make sure you hae adequate ride height before anything, as Tyson and others have suggested.

But, check out the dampers as well. They could be sports set full stiff, which would be an easy adjustment.

I think the overall numbers are alright, a tad light for the front but good side to side and corner to corner. I agree the missing front spoiler could be an issue at higher speeds. As far as shocks go, the ones you have are new and are quite good. With stock torsion bars re-valving isn't necessary. You revalve to control compression and rebound of the torsion bars; stock tbars and the Bilsteins are designed to work together and give you correct rates.
Could come back to alignment, but I'd put the chin spoiler on and try again before adjusting something else. One thing at a time will let you feel any change.

I would guess its the combination of 19mm bar (which is not that stiff) in combination with possible a Bilstein sport shock absorber (which are very stiff). I'd check to see which one and consider revalving to match your needs. I first had Bistein sports in combination with my 22mm bars and I thought they were very stiff. Since revalving, the ride has been considerably more comfortable.

I agree with Tony, my son's '71 car had the same issues after a long restoration. Specifically, at speed the directional stability was zilch! Alignment brought this to an excellent feel. If you want the low stance the rough ride can only be fixed by raising the spindles. This was done last year.

What are you comparing your car's stiff front end to? Other car's front ends? Your car's rear end? I thought my front end was terribly stiff (22mm bars/Bilstein sports), when compared to my car's rear. My rear shocks (28mm bars/Bilstein sports) have, in fact, begun to wear out.

I would also bet you have Bilstein sports up front. I run them with 19mm torsion bars in my longhood, and the front end is very very stiff.

You might want to sell your sports and switch to HD's.

Thanks for all the input,
How does one get the spindles raised? If this was done along with removing a segment of rubber and the big steel washer would I feel a difference. And dd74 is correct Ive only driven this car for 1500 miles and never drove a 911 before so I don't have much to compare the cars feel to.
Just came back from a ride and took a flat 30 degree turn at 45mph on a smooth road and the steering wheel was jerking and fighting me along with the front end not settled,planted.
Maybe TonyTT is right and go back to alignment.
The car is a blast to drive and I put a ton of cash into it, engin rebuild, training, complete interior,ssi,M&K2/1,short shift,fuel lines and more $$$$ than I should have and enjoyed the challenge. Ill get her right.

I'm surprised you have it that low with 19mm front bars.... do you want it that low? IS it a track car? street car? what % of each...

If not, get it raised, and aligned - + corner balanced.

IF so, then the struts may have to be pulled - not sure if they can be welded in situ.

Where are you located? Someone may know the best race type shop in your area. IF there is no one trustworthy for this particular hotrodding mod, then they would still have to be pulled, even if a shop could do it in situ.

If the thick washer is still in there, then removing it may solve 90% of your problems. You'd be amazed what another 1/2" of suspension travel can have on ride quality and handling.


You can remove it without disturbing the alignment settings. Just jack up the car until the front wheels are off the ground, then remove the large nut on top. Do not disturb the three that are holding the upper strut mount to the chassis.

Then just compress the strut until you can remove the spacer washer, and reinstall the strut shaft into the upper mount.

You might check with the shop that installed the shocks to see if they know if the spacer is there before you drop the shock and have a look. If they are certain it's there, then go right ahead and remove it. If you want details on raising the spindle, use the 'search' in the 911 Tech Forum and you should find a few good threads with pictures.

I forgot to add, nice looking car!