914-6 GT fast road/track suspension settings Options

[amallagh]

Hi,
I'm just about to have the suspension set up on my 914-6 GT project and wanted to see if anyone had any advice. I have never done this before (my first 914) and was looking for a fast road/track set up. I think the range of settings people seem to talk about on Toe and Caster is fairly small but camber settings vary wildly depending on what people want to do and type of tyres.
I know the theory about track set up and measuring temperatures across the width of the tyre but this car will spend more time on the road than track (albeit I could be called a spirited road driver!), and tracktime ain't cheap !
Suspension components are :-
FRONT -
Sway-a-way 22mm hollow torsion bars
Weltmeister 22mm sway bar
Bilstein shocks
Weltmeister camber plates
Fuchs 7X15s with Goodyear Eagle GSD3 205/50s
REAR -
Weltmeister 140lb springs or 180lb springs available - need to decide which ones are best to use ?
Weltmeister 16mm sway bar
Koni adjustable shocks (yellow)
Stable Energies rear strut tower camber brace.
Weltmeister chassis and suspension arm stiffening kits
Fuchs 8X15s with Goodyear Eagle GSD3 225/50s
Tyres will be

This is what I was planning to do based on some previous indications:-
FRONT -
Toe in(each wheel)- 10'
Camber- 1 degree negative
Caster- 6 degrees
REAR -
Toe in(each wheel)- 15'
Camber- 1.5 degrees negative

#############################################
I think these are the factory settings -
FRONT -
Toe in(combined) 20' +/-10'
Camber- 0 degrees +/-20'
Caster- 6 degrees +/-30'
REAR -
Toe in(each wheel) - 0 degrees +15'
Camber- 30' +/-20' negative
##############################################

I would welcome any advice or opinions. If anyone has any advice on initial settings for the rear Koni shocks then that would be a real bonus. All advice gratefully received and without prejudice.
Andrew

[amallagh]

I'm intrigued. What exactly is auto-X ?
Is it some kind of mixed surface racing? We would call that Rally-X in Europe.

This car won't see the rough stuff.
Tight UK race tracks, hillclimbs and sprint events on variable tarmac surfaces.

Also planning to do some long distance rallies in UK and across Europe which involve odd speed tests in various types of venues from car parks, to race circuits to farm yards.

From comments so far it sounds like I should go for mild negative camber of about 1 degree all round and about 10'-15' toe in on each wheel, front and rear.
The original manufacturers settings were 0.5 degrees of camber on rear and none on the front. Seemed like another bit of simplistic logic to stick to this front to rear differential on first set ,up but no one seems to have supported this philosophy so I'll drop this. Please speak up if you think I have misunderstood things.

I understand the comments about measuring tyre temperatures at the track but might not get on track until next year and just want to get it as close as I can based on the best advice from you guys who have experience.

[grantsfo]

I'm intrigued. What exactly is auto-X ?
Is it some kind of mixed surface racing? We would call that Rally-X in Europe.

This car won't see the rough stuff.
Tight UK race tracks, hillclimbs and sprint events on variable tarmac surfaces.

Also planning to do some long distance rallies in UK and across Europe which involve odd speed tests in various types of venues from car parks, to race circuits to farm yards.

From comments so far it sounds like I should go for mild negative camber of about 1 degree all round and about 10'-15' toe in on each wheel, front and rear.
The original manufacturers settings were 0.5 degrees of camber on rear and none on the front. Seemed like another bit of simplistic logic to stick to this front to rear differential on first set ,up but no one seems to have supported this philosophy so I'll drop this. Please speak up if you think I have misunderstood things.

I understand the comments about measuring tyre temperatures at the track but might not get on track until next year and just want to get it as close as I can based on the best advice from you guys who have experience.

LOL! I didnt realize you were in UK. AX is timed circuit event around cones. If you plan to do hillclimb you may want to jump to a higher rear spring rate. My car in a recent hillclimb was pushing terribly with 250 lb rear springs (no rear bar) and 19 MM front torsions with a 22mm bar set at soft. I had same size front and rear radial slicks. But again I think it depends on your driving style and the track or hillclimb venue. 914's are great cars as often on bigger courses you can change your driving style to accomodate a car that pushes in the turns.

Camber is fairly easy to change, start at -1 and see how it works for you. From my perspective the 914's dont turn as well with less than -2 degees of camber in competive events with radials. Remeber stock specs from Porsche were for general public - always better to put a car with understeer in the hands of those with a wide range of drivning skills. The 914 will bite anyone who goes into a corner and lifts and doesnt get back on power smoothly regardless of setup.

Its important to note that some of us here only drive track or AX cars so we are a bit jaded. I want the car to turn at expense of car being a bit darty on the street.

You may want to go to 914club.com site and ask there too. Brad Roberts is the suspension guru that I would trust with suspension setup questions. Send him a PM.

This post has been edited by grantsfo: Aug 7 2007, 03:22 PM