Suspenision Set Up

[domtoni]

Guys,

I had some shop here in the area lower my car 5 years ago. I am not sure they did the best job. These are the results. I asked for a
"fast road setting".

Height - measured from ground to top of wheel arch
Front 24.5" left 24.25" right
Rear 23.5 left 23.0 right

Camber
front 1.5 left 1.5 right - both in degrees rear 2.0 left 2.0 right - both in degrees

Castor
8 degrees and 2 degrees on turns

From what I have read, the car is actually too low for a street car, and the rear should be higher than the front.

How is camber and castor?
Does anyone have the specs from the tech info bulletin from Porsche for a late LWB? and if so, what are the dimensions.

Thanks
Dom

[Lightweight_911]

Dom - as an approximate guide, on level ground & ideally with 3/4 tank of petrol, std ride height from the ground to the centre (highest point) of the wheelarch should be 25.5" (front) & 25" (rear).

It looks as though your car has been lowered approx 1" at the front but 1.5"-2.0" at the rear.

Camber & caster settings are different to factory settings too - std settings are:

camber (front) = 0 degrees +/- 20'

camber (rear) = -30' - 1 deg 10'

caster = 6 deg 45' +/- 45'

It has probably been set up at the rear so that the ride height is equal from side to side with the driver sitting in the car.

What size tyres is the car fitted with ?

I would suggest maybe just raising the rear by a small amount - say 1/2" - this will also automatically reduce the rear negative camber slightly.

[domtoni]

Andy,

Thanks for the kind reply.

Tyres are 195/65 x 15 Pirelli P7s on 15 x 6 Fuchs wheels.

The car weighed in at 1080 kgs when lowered. I think the tank was full.

Any further recommendations?

Thanks
Dom

[Jeroen]

the camber settings are pretty agressive for a street car, but if you do a lot of spirited driving and/or trackdays, it should work very well

can't comment much on the definitive ride height measurements relative to the fenderlips
as a (very crude) rule of thumb, the fenderlips shouldn't be lower than the top of the tires (to prevent bottoming out of your shocks, messing up the suspension geomitry too much, ground clearance over speedbumps etc.)
ideally, you should have your car cornerbalanced

what are the toe settings?

how is your tire wear across the tires?

[domtoni]

Toe In Front is 1 degree, rear toe out is 1/2 degree.

How does this sound?

Thanks
Dom

[hot66]

I'm going to have my car re-done soon. What are the best settings for 'fast road' . Does anyone suggest anything different to Dom's ?

My car is already at the ride height I want and runs quite a bit of camber up front... but I'm not sure what the settings are as they were done by a previous owner



Any recommendations?

[Glasgow 911SC]

Check out this link at Pelican

[domtoni]

Just got the recent issue of Excellence magazine, and they listed the settings for fast road. Jim Pasha advised the proper toe in camber castor settings. I am out but will make the post once I get back.

Dom

[domtoni]

Guys and Gals,

Here is what I found for both 911 and 912s for lowered cars.

These are from Bruce Anderson in the states.

Height - as stated by Lightweight Andy
Front - 25.0 inches
Rear - 25.5 inches
Taken from the pavement to the wheel arch lip.

Lowered settings - not so far from Lightweight Andy's reply on the normal settings:
Front
Camber
0 degrees +/- 10 minutes
Difference right to left 10 minutes

Caster 6 degrees 5 minutes +/- 15 minutes
difference right to left 30 minutes (?) my notes are not the best

Toe in +15 minutes +/- 5 minutes with wheels

Rear
Camber
1 degree negative +/- 10 minutes
difference right to left 20 minutes

Toe in +10 minutes +/- 10 minutes
difference left to right 20 minutes

Jim Pasha recommends that the front camber at the lowered height should be 1/4 to 1/2 negative to gain the most adhesion.

One further comment from Chris over at 2+2 regarding using alignment machines. It may be difficult to get the car spot on, and as Davidppp said, one may be able to do a better job using string and simple measurement.

One last comment: the car should have the forward slop of 1 to 1.5 degrees. One Porsche race mechanic in San Diego said that the forward slop was more important than the exact height.

If I made any mistakes, or something doesn't make sense, let me know.

Dom

[domtoni]

Rebuilding a Suspension System
General Overview
I did not do the disassembly or assembly on the car. I sourced all the components and installation information and gave the job to a local shop to complete.
The car was previously lowered to ridiculous levels by a local firm. All previous work was documented in this link. The car bottomed out regularly. Despite the bottoming the rear shock valves were not destroyed.
All bushings were ancient, and the car suspension settings were way out of adjustment.

Rear Suspension
I replaced the rear spring plate with the ER poly bronze bushings. There were first installed without the torsion bar. The required force to move the spring plate was less than 1 kg force.
I replaced the red shock absorbers with the gas filled yellow shock absorbers because the yellow shock maker has better customer service and warranty. Two tow hooks are installed onto the shocks.
The car has no rear anti roll bar.

Front Suspension
This all went together well, new red shock inserts where installed into the struts, new turbo tie rod ends onto the steering rack, new rubber drop link inserts, and the ER bushings. For the most part, assembly went well. Front anti-roll bar is a 15 mm Porsche bar.

First Impressions
Chris, the technician, showed me some photos of how Porsche Zuffenhausen set 928 suspensions. They literally did a drag race start over a series of speed bumps. The bumps were hit at speed, and believe it or now, the car was then ready for its final adjustments. He used a similar technique here.

A road going to a local supermarket is loaded with speed bumps. Chris drove the car over the speed bumps and found the car absorbed these very well. I tried the car and hit the bumps at a speed lower than he did, and found the car absorbed the bumps far better than I ever expected. I did a quick 360 degree turn in the car park with the car accelerating, and the car went around as if it is on rails. The steering is direct, toe in remarkable.

I think that the car’s driving performance is better than new. All I need to do now is get the body redone, and with the underside sealed, and I will have a new car. What else can I buy in today’s world, for what I have spent over 30 years, that is this good and still worth its money.

[sladey]

HI Domtomi,

Out of interest which bits did you buy from the Elephant Racing site (there's a million & 1 suspension options on the site)

Also is it squeak-free?

Cheers

Mark

[domtoni]

Slady,

I bought the stuff elsewhere. If anyone needs these bits, let me know.

The bushings have to be tight when insalled on their mating components.

The ride is good, the car points and squirts incredibly well. I would say better than a new car.

Best
Dom

[james911rs]

Can i ask who did this work for you, as you are local to me, im only in Bridgnorth and am very curious of who round here is capable of doing this job.
Thanks

[hot66]

Dom

what ride height did you end up at?

I have just measured the rear of my car ( running 195/65 15's ) and it is at 23 3/4" (ground to wheel arch through centre of wheel).

By my calculations I need to set the freont end to either 24 1/4" (stock front / rear ratio) or 23 1/4" for a more agressive stance, which seems pretty low

[Nick Moss]

James

That is low. I set my cars at 25" rear and 25.5" front.