E46Fanatics - View Single Post - Concept for roll center correction. Fabricators and engineers please chime in.
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Old 10-02-2012, 06:22 PM   #51
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Join Date: Nov 2003
Location: Fort Worth, TX
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Originally Posted by IrocThe325i View Post
so this wont work?

Attachment 471815
No, while that changes the angle of the control arm, it doesn't change the position of the ball joints. The angle of the imaginary line drawn between the ball joint pivot points is the same.
Originally Posted by WDE46 View Post
I'm surprised nobody has posted a diagram of a MacPherson strut roll center. I took this from my vehicle dynamics textbook. It will help you visualize what can be done to lower the roll center.

From the diagram you can see that you can lower the roll center in several ways:

1. Lower ride height
2. Lower innder joint
3. raise outer joint
4. Increase shock lean towards outisde (more vertical from picture I believe)
5. increase track width
You want to raise the roll center, not lower it.
Originally Posted by mkodama View Post
We are trying to raise the roll center to correct it after lowering it when we lower our cars.
Correct, you want to decrease the distance between the roll center and the center of gravity, known as the roll couple. Theoretically, if the roll couple is 0, then the car will have no body roll. But you have to remember the center of gravity and the roll center are always moving, therefore the roll center won't remain 0.

For a street driven car don't waste your time, spend the time/money on better dampers or more track time.

Last edited by vaio76109; 10-02-2012 at 06:23 PM.
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