Pesty

Just a thought do you have the rear undertray fitted?

Heirsh

17 in wheels and you are running 44psi in the rear? That is way too high for 17's isn't it fellas?

Have an alignment shop at least measure your setup. Don't get me wrong, I've tinkered with toe on the front and camber on the front, but I wouldn't personally mess with the rears just because I don't have the right equipment.

I'd doublecheck your rear toe. I've got a 964 with over 100k ont he clock. With the stock suspension it was fine at 125. By fine I mean it felt planted and steady, even over a few bumps. if yours feels wrong at speed something is definitely wrong.

I;'ve seen it written many many times that these cars are super sensitive to suspension setups.

Bearclaw

This car was rebuilt, correct? Are you certain you have everything lined up in spec?

I just had mine up to 115 over the weekend. A '91 , everything's original, but with new tires and a good 4-wheel alignment. Rock steady, felt like I was going 60.

garrett376

Your car is not set up right, somehow. Figure it out before you go fast againi!

A 964 should be very solid at high speed, whether at stock ride height, undertray or not, wing up or not, cabrio top open or closed, or windows open or closed, or tire pressures way off.

jeffnudd

Are there specific measurements for ride hight anywhere so i can check i out and make sure its set up correct, this is something i think i should check out.

springer3

I have never lost them on a Porsche, but my E-class was frightening at speed until I found a loose bushing in the front sway-bar. Have you verify those are solid in all 4 corners?

Mike_964

When using 17" you should have the same pressure (36psi) both front and rear.
When I ran with 44 psi in the rear (because the sticker said so, but it was refering to 16"), I also almost nearly had an accident when doing 100 mph. It felt very unstable, almost like running on flats, because it was driving on the middle of the rear wheels.
After changing pressure back to 36 psi I can do 160 mph without any sign un unstability.
You can't trust anything else you try, if you are running too high pressure in the rears as the 964 is very sensitive to that..

jeffnudd

I will try the car at 36 psi all round, but i think i found the problem yesterday, unfortunatley i didnt get a chance to post up the problem last night, anyway i checked the pressures again just to make certain and found all wheels ok except for the left hand rear which was down to 26psi, it didnt look low so i check the gauge i was using and sure enough it was reading correct, i took it down to a local tyre centre to see if he could sort out the leak which i thought was the rim or valve and to my horror he found a bloody gread screw stuck in the centre of the tread, although i wasnt happy seeing that i thought back to Sunday when i almost lost the car and im pretty sure this problem was the culprit.

Porsche_Red

I had the same 'floating' trouble with my car when I first purchased it. Two things cured it (both done at the same time) a recognised specialist in setting up 964's and a new set of front wishbones which are prone to wear in the mountings hence flexing under strain.