911 feels 'jumpy' in turns. What's the cause?

Guys,

After getting my first Porsche, an '87 911 I noticed a peculiar symptom. During hard turns, the steering wheel feels wobbly and the front end seems to jump up and down. I also feel vibration through the steering wheel. Yet the car seems to make tight turns OK, doesn't slide or lose grip. I don't think this is normal. Must be some component in the suspension/steering that's starting to go. Which one?

Does your car have wider wheels than stock? or has it been lowered? Both of these things can cause tire rub on the inner wheel well during sharp and/or hard cornering. Check the inside of your wheel wells for signs of rubbing particularly along floor pan edge. my $.02 and not worth a nickel more! Of course there's alot of things else it could be, out of balance tires, bad front wheel bearings, worn- tie rods, ball joints, swing arm bushings. good luck!

Tough to say without seeing/driving your car, but you may just be experiencing "normal" 911 bump steer and road feel. The 911 suspension transmits a lot of information to the driver via the tires and suspension. Have you driven many other 911's and if so is the feel of your car really different in similar conditions?

I've driven quite a few Porsches, but mostly concentrated on straight-line acceleration, weird noises, etc. I never took hard-turns. So you may be right, that's how it normally feels. I'm taking it to a mechanic on Friday - wanted to get a heads up before then so I could talk intelligently to him

Here's my two cents.
I have an 89 Targa, and during hard cornering, the steering and the way the front-end definitely behaves in the way you're talking about. But since I haven't driven your car, I can't tell you if what you are experiencing is normal.

The steering wobble is caused by the front tires grasping for grip. You can experiment with this by using different amounts of throttle at different points in the corner. If you boot it hard right before or near the apex, before unwinding the steering, the weight transfer to the rear will unload the front (big understeer here) and cause the front tires to work extra hard. Also, if you modulate the throttle at all, the weight transfer from the front to rear, and vice versa, will cause the front end to oscillate in an up and down motion.

This is actually a good thing because the steering (people call this 'feel' and 911s exhibits this better than any front-engine car I've ever driven) is telling you exactly how much grip is available at the front; and once you're used to it, its fun and can teach you how to corner on the limit.

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DW

89 Targa

In hindsight (which is 20/20 right?) I've gotta agree with DW, forget all that crapola I wrote earlier about tire rub and such. Sometimes I just plain miss the question!

I bought my first in October, and have put over 15 k miles on it. This car has taught me much about driving and I am still just getting the hang of it. I love the way the steering wheel feels. This car has taught me about the correct number of fingers to use on the steering wheel. The correct number is really TEN. I imagine I will eventually be able to sense more about available front traction.

Vibrations, the harmonic kind that is, are probably not an appropriate feature of these cars. They would be caused by something such as tire balance and wheel trueness.

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'83 SC

If you have too much Negative camber you
can get a twitchy feel. The PO (previous
owner) of my car did alot of Autocross events so he had the max negative camber which made the car feel twitchy. He also
installed heavy duty sway bars and sticky tires.

I would first do a visual inspection and make sure no suspension parts front and rear are broken or loose.

Good Luck
Joe A

toe-out can also make the car twitchy, and some drivers intentionally use it to increase turn-in for autox -- terrible on the street though as the car will "wander" around really easily.