914 ride height?/raising rear/trailing arm ideas? Options

[slugmika]

I'am going to raise my rear suspension pick up points and would like to know what should be the ride height?
I found that front shoud be 108mm from torsion bar center to spindle center.
What is Porsches recomendation?
I know that some of you have raised pick up points, have you used the factorys specs or what.
How much have you raised those?

And finally, is there any poin to make the stock kind of trailing arms? I have allready made a jig with stock trailing arm dimensions. Those would use stock bearing hub but otherwise made of tube. We would use uniball's rather than stock kind of bushings.

Car is now on a table and it would be easy to make allmost anything, so if you have good ideas feel free to share

Thanks
Mika

[groot]

Mika... you're asking the right questions and don't worry about not being an engineer, it's only a geometry issue.

While your static toe may be zero, what happens when that wheel goes into jounce? That's what's important... the toe change with suspension movement.

I have never talked to any of the original 914 suspension engineers, but my best guess for their original setup is this...

I think they set up the rear trailing arm for toe out in jounce to produce roll oversteer to correct for the horrible front geometry, which has roll understeer. So, returning the arm to its original angle may not be in your best interest. This car does not need anymore oversteer.

The original setup may have been okay for production, but we change many things on these cars and the original "balance" of spring/damper rates and stabilizer bars is long gone.

But, don't take my word for it.... you've got your car on a plate. Measure the toe at below ride height, then raise it 1/4" and measure the toe, repeat until you've reached full jounce. Plot the toe change and determine your ideal starting angle of the trailing arm by tring to minimize toe change over your travel.... it won't be zero and a little toe-in gain is preferred over any toe-out gain.