Ride Height / Balance

[mm86911]

Vehicle is '86 911 Targa with 16" Fuchs. Ride height (measured from floor to fender lip at center of wheel, 1/2 tank fuel, no driver) as follows:

RF 24.75"
LF 24.5"
LR 25.375"
RR 25.375"

While the car looks aggressive (really like the front at current height) the rear seems a bit high. Hoping to make the cut for first DE event early November and have the following questions:

1. Why is front off by .25" from L to R?
2. Is rear too high?
3. Will lowering rear affect height of front?
4. Should I spend the money on proper corner balance?

Suspension gurus please advise.

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Mike - Atlanta
'86 911 3.2 Targa

[Jack Olsen]

Front measurement should be half an inch higher than the rear. This will still produce a downward-raked look. It's just that the front fender cutout is larger.

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Jack Olsen
My Rennlist page • My Pelican Gallery page • My Porsche Owners Gallery page

[R22tech]

Hi Mike. Just a reference here:
mine=85 w/16" stock everything
1/2 tank no driver

l.f. 24 3/4"
r.f. 25 1/4"
l.r. 24 1/2"
r.r. 24 3/4"


I guess mine might be off as well-I'm interested in the response to your question.

[Howard Nelson]

To optimize handling, I think the most important thing is to balance the weight between the front L and R and between the rear L and R tires. If your car is perfect, the fender heights will represent this... but to be sure, you should get a corner balance. In may area (Chicago), corner balance and alignment runs ~$250. Good luck.

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1972 911T Coupe

[Eric Coffey]

I would definitely recommend getting the car corner balanced and aligned. It will make a huge difference. Torsion bars will sag over time and re-indexing the them is the only cure (you can raise/lower each corner a little with the rear eccentrics and front adjustment screws, but this "weight jacking" will effect the balance). If you do get the car corner balanced, put a half tank of gas in, and see if it can be done while you are there to sit in the car, instead of them just throwing a 75 pound weight in your seat. As far as ride height goes, I would start with the rears at 24" and the fronts and 24.5". Anthing much lower than that will negatively effect the suspension geometry. This will give you about 1 degree forward rake. Some people prefer to keep it simple and use the same measurements all the way around, witch gives you a little more forward rake. Also, this is the perfect time to dial in a little negative camber, especially if it is going to see frequent DE events. How much is up to you, but I wouldn't exceed -2 degrees, as it will wear your tires a lot quicker. Lastly, if you haven't done so already, you should shim your steering rack with spacers to give your tie rods the proper geometry to reduce bump steer. Have fun at your DE!

-Eric

[mm86911]

Thanks for the replies.

I have Recaro Sports seats on order (replacing 8-way power leathers) - should I wait until they are in the car before the balance (will it make a difference)?

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Mike - Atlanta
'86 911 3.2 Targa

[Mike Feinstein]

Mike,

You might want to call Robin Hayes at Black Forest (770-967-3331). His shop is at Road Atlanta (adjacent business concourse) and he is a wizard with Porsche suspensions. Robin sets up cup cars for track events on a daily basis. He's a nice guy and you can stand in front of his shop door and watch Panoz track-test their newest toys around turn 3 (I think).

Your car does have a good bit of rake but I must say it looks great! Not sure if the resultant forward shift in weight will help with handling though (more weight over the front wheels).

Hope you get into the DE. I'll come watch the show. . .still no rollbar in the cab.

Best,

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Mike
94 C2 cab