Lowering an Early 911

[matteo68]

Some interesting guidance regarding lowering the 911 S and 914/6 competition versions in “Information regarding Porsche Vehicles used for Sports Purposes, 2 Ed” here:

[matteo68]

And this geometry set-up data too:

[CraigB]

How do you adjust the castor? When I was under the car last it appears that the a-frame fixing location have no adjustment to then

[Gary71]

With difficulty:)

Joking apart you can theoretically move the top mounts within the body by undoing the clamp bolts under the bonnet and levering the strut back and forth.

In practice it’s quite hard and if they’ve been in the same position for 20 years and covered in underseal it may be a case of strip everything and clean it all first.

[matteo68]

I think that’s exactly what Chris at Center Gravity does

[KS]

I think that’s exactly what Chris at Center Gravity does

I don’t think there’s any other way to set the castor. Very straight forward job.

[911hillclimber]

For DIY you need a flat set of 'pads' and my garage floor was out by 6mm. Getting the pads level was tricky.

Once done all the angles were quite easy to set, but ride height and corner weighting was hard but I borrowed corner weight scales to do my car.
I started with the ride height generally set first, then the corner weight adjust and re-check the heights.
Then set the rear angles, then the fronts.

Had to repeat several checks to get things close.

[Spit Nolan]

On the front of mine winding the bolts down wasn’t enough. So I popped the end off and rotated it one spline then fine tuned with the bolts afterwards.

The rear I measured the angle of the springplate and worked out the angle it would need to be for a 1” drop. It worked out:

Drivers side started at 30.3 degrees
Lowered to 22.8 degrees

7 inner splines then down on outer

Passenger started at 30.6 degrees
Lowered to 23.1 degrees

I have now decided it’s too high at the back so I need to work out the drop I want then do same again. Then need to get it all aligned properly.