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Originally Posted by choaderboy2
My latest stuff is based on experiances gained working with Motorsports and Nismo suspension engineer, Jeff Lesher who is a hell of a guy.
He taught me about frequency matching of the front and rear suspensions, basicaly the rear suspension needs to have a higher natural frequency than the front so bobing and other chassis exciting, traction reducing effects of bumps and undulations can be reduced. You tune so they will cancel out in 1/2 cycle.
Basicaly in a close to 1:1 motion ratio suspension like ours, this means the rear spring rates must be higher than the fronts. I am starting to do this based on his equations, using roll bars to make up the gradient in roll stiffness that this causes.
The results I have experianced so far are pretty interesting, bobing can be greatly reduced without needing more damping and the tires are getting shocked less with less bobbing and less damping. It seems to work well.
Also a big trend in the motorsports world is to adjust dampers so when you intergrate piston velocity over time the curve has an equal distribution for attack and decay. Need LDPT's to do that which are expensive but I do have the dfata loggers now.
So lately my spring rate recomendations are way different from the status qou. I will have more experiance with this so and will be changing some of the good old standard rule of thumb spring rates soon.
The OEM's are catching on with this lately. Wonder why the Spec V, Maxima, Altima and some other makes of car have such a high rear wheel rate?
Mike
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Is this something that can be applied to the street then? What sort of front to rear ratio for the spring rates do your calculations show we need? Has testing showed the calculations are pretty close to what actually works? Werent you working on a large rear sway bar awhile back? With the stiff springs in the rear I'd think you would be going with a larger sway bar in the front now. One last question, whats an LDPT? Some sort of data logging sensor?
