911 handling differences
01-29-2003, 04:28 PM
#1
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911 handling differences
As a relative newbie to Porsche, could someone please elaborate on the handling differences between the various generations of 911's. I understand the earlier ones had torsion bar suspension, swing axles, trailing arm (?) and, later still, the 993's beautiful aluminum suspension (which I think is still used today, correct?).
You always hear about 911s being "tail-happy" and "snap oversteer". What are the differences between the various suspension setups mentioned above and how did each affect the oversteer situation (which I understand was all but eliminated with the 993)? How does camber play into the equation? How did the respective suspension setups handle camber changes? Also, what is "bump steer"?
A lot of this terminology gets thrown around, but I've never felt competent about all of its meaning. Thanks.
You always hear about 911s being "tail-happy" and "snap oversteer". What are the differences between the various suspension setups mentioned above and how did each affect the oversteer situation (which I understand was all but eliminated with the 993)? How does camber play into the equation? How did the respective suspension setups handle camber changes? Also, what is "bump steer"?
A lot of this terminology gets thrown around, but I've never felt competent about all of its meaning. Thanks.
01-29-2003, 05:57 PM
#2
Rennlist Member
Not 911 specific, but the <a href="http://www.fernblatt.com/longhurst/suspension_bible.html" target="_blank">suspension faq</a> may answer some of your questions. There is also a 993 suspension faq on <a href="http://p-car.com/susfaq.html" target="_blank">Robin's site</a> .
01-29-2003, 06:11 PM
#3
You could right a book about that, and still not cover it all! In fact, that's probably your best bet to cover all of that, especially the historical stuff.
To cover a few quick points very briefly, basically the newer the car the less tail-happy it is. Camber is one of the alignment settings. Proper camber is critical to a well-handling car. Bump steer is when the toe angle changes when the wheel goes up and down. E.g. if you have the wheel turned to a 15 degree angle, it should stay at that 15 degree angle as the suspension travels. If that 15 degree angle changes, that’s bump steer. It’s typically caused when the geometry of the steering arm and A-arm is changed due to something like lowering the car. Since this happens within the geometry of the suspension components, you do not feel this in the steering wheel.
Tom
’95 993
To cover a few quick points very briefly, basically the newer the car the less tail-happy it is. Camber is one of the alignment settings. Proper camber is critical to a well-handling car. Bump steer is when the toe angle changes when the wheel goes up and down. E.g. if you have the wheel turned to a 15 degree angle, it should stay at that 15 degree angle as the suspension travels. If that 15 degree angle changes, that’s bump steer. It’s typically caused when the geometry of the steering arm and A-arm is changed due to something like lowering the car. Since this happens within the geometry of the suspension components, you do not feel this in the steering wheel.
Tom
’95 993
