Reverse engineering my unknown suspension

[Jonny042]

The last owner of my car did not have reciepts for or knowledge of the suspension work that had been done to the car by the owner before him.

It has wider 16" replica wheels, has been substantially lowered and also has green bilsteins, and turbo tie rods. I am wondering if the same person may have gone deeper into the supsension and put in stiffer bushings and bigger torsion bars.

If I try to bounce my car by kneeling on either the front or rear bumper, it hardly moves. I do not have a stock car locally that I can compare it to. It is easily as stiff as my 2003 mini cooper s, which rides like a coal cart, but the 911 makes it feel mushy!

Also, the front end has developed a loud squeak from both corners that I would normally associate with aftermarket bushings.

How loud/harsh are the bushings on a stock 911? I am wondering if my car has monoballs installed..... any guesses?

[Jonny042]

Forgot to add pic:

[na2ub]

You can easily pull one of your front torsion bars and measure it with a metric caliper. Just remove the adjuster screw and wiggle the adjuster cap loose. The T bar should be able to pull out, so you can measure it. If you have the measure of your front bar, you can guess your back bar, by plus 6 or 7 mm.

[johnsjmc]

Stock rubber bushes don,t squeak. The car might have poly front bushings. They are inexpensive and a good product but they need some grease and slots cut to keep them lubed. The green bilsteins is a very common option on SCs. It often came with the 16 in wheels in a pkg . Standard T bars are very stiff when you just try to depress the bumper s you may not have more than front bushings. Have the swaybars been changed? Std in a SC is 20F and 18 R (I think)

[Jonny042]

Thanks for the replies... I did just get the car, so hopefully this weekend I can get under it and have a close look.

Based on the above picture, any chance that the car is sitting on the bumpstops, front or rear?

[johnsjmc]

The side marker light says it is a Euro model. I think stock Euro or ROW(Rest Of World) height is lower than US.Still not on the bumpstops.

[onboost]

Originally Posted by na2ub

You can easily pull one of your front torsion bars and measure it with a metric caliper. Just remove the adjuster screw and wiggle the adjuster cap loose. The T bar should be able to pull out, so you can measure it. If you have the measure of your front bar, you can guess your back bar, by plus 6 or 7 mm.

You may also be able to tell what size bar you have jus by looking at the end of the bar. Most of the quality manufacturers stamp their bars with the size.. some stamp both ends, others only one side.

The squeaky bushing I think would indicate that it's not stock.. and as someone stated, looks like euro ride height.

Good luck & have fun!

[gtc]

Sounds like you have bigger torsion bars and poly bushings.
It's a pretty easy weekend DIY job to go through your front suspension and replace your bushings with rubber. It would make for a convenient time to check your brakes and repack wheel bearings too.

[Steve@Rennsport]

Originally Posted by Jonny042

Based on the above picture, any chance that the car is sitting on the bumpstops, front or rear?

It looks low enough that it doesn't have much suspension travel left.

If it were my car, I'd either install some raised-spindle struts and shorter rear shocks to restore lost supension travel or raise the car for better handling and ride quality.

[tonythetarga]

[QUOTE=Jonny042;5572310]
If I try to bounce my car by kneeling on either the front or rear bumper, it hardly moves. I do not have a stock car locally that I can compare it to. It is easily as stiff as my 2003 mini cooper s, which rides like a coal cart, but the 911 makes it feel mushy!
[QUOTE]

This 'bounce' method does not work with torsion bar Porsche's. The 'spring' is a horizontal steel bar that twists at one end as the suspension travels...hence the name 'torsion' bar.

Dismantling the suspension to check t-bar size is a bit of a stretch unless you want to re-do the bushings or up-size or down-size the t-bars. You will need to realign and corner balance the car if you start messing with this. How bad ( read how much $$$) do you want to know?

[Jonny042]

Originally Posted by Steve@Rennsport

It looks low enough that it doesn't have much suspension travel left.

If it were my car, I'd either install some raised-spindle struts and shorter rear shocks to restore lost supension travel or raise the car for better handling and ride quality.

Hmmm...... very good advice. I've always tried to make it a policy to add back the lost travel when lowering. Not always possible but a good thing to aim for.

Being new to the 911 world I did not know that raised spindle struts or shorter shocks exisited, but will look into both of those things. Are they readily available and/or affordable??

[Jonny042]

Originally Posted by johnsjmc

The side marker light says it is a Euro model. I think stock Euro or ROW(Rest Of World) height is lower than US.Still not on the bumpstops.

Well, the only thing Euro about mine is the side markers (actually wired into the parking lights - wrong!) and the rear signal lenses.

I think the current height is less than euro. But I don't know if the 10 mm spacers are gone or not and that would help travel a bit.

Thanks everyone, for their help!

[dad911]

Could be squeaking if stock rubber bushings are worn, and torsion bars are rubbing.

[Steve@Rennsport]

Originally Posted by Jonny042

Being new to the 911 world I did not know that raised spindle struts or shorter shocks exisited, but will look into both of those things. Are they readily available and/or affordable??

Call me,...