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Lowering Springs for 2006

Cayman S 
4K views 3 replies 3 participants last post by  WJPoage 
Welcome to the forum - and to the Cayman, again.

From working on the car I am sure you know that it is the geometry change that creates the harshness, not so much the spring rate. Lowering the car removes the angle, and therefore the force couple, on both the control arm (roll) and trailing arm (dive, squat). Lowering it too much also removes all dynamic camber gain and worsens handling. In addition, it lowers the roll center, increasing the roll couple, which actually makes the car roll more, not less, for a given spring rate - encouraging folks to use even stiffer springs or anti-roll bars.

The Cayman is delivered with about 7 degrees of angle in the control arm (pointed down and out). This decreases by about 1 degree for every 0.2 inch the car is lowered, so lowering the car 1.4 inches removes all angle from the control arm and most of the angle from the trailing arm. The control arm angle reduction increases the roll couple (bad) and kills camber gain (bad), and the loss of trailing arm angle reduces the force couple that compresses the spring (overly limits squat), making the car harsh and prone to a flat slide under throttle (really bad). Think about a motorcycle swing arm and how the force vector is transmitted to the spring/damper.

These issues can only really be corrected with new uprights or altering the pickup points in some other way.

So, all of that said, you are probably better off with the R springs or a set of coil overs that allow you to control the ride height (and limit the drop to 0.8 inch or so).

Cheers,
 
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