Double a arm suspension help needed!

[slugmika]

Hi All
I'am racing my porsche 914 in Finnish Roadsport A class.
I started to built unequal douple A arm suspension and would really like some help.
If someone could help me to check if my calculation are anywhere near what they shoud be.
I have 27cm upper control arms and 36cm lower ones. Those are 16cm apart horizontally.
Arms are level to each other and horizontaly so roll center is in ground level.
Total suspension travel is 9cm, 5cm in and 4cm out. I would like to know if there is enough camber gain in full 5cm. If you guys could help it would be great, i don't have suspension software so i have drawn these to paper and measured that. Is that enough difference in lenght to get proper camber gain?
It would be great if someone of you could help.

Thanks

Mika Särkelä
bogeyracing
Finland

>> Edited by slugmika on Saturday 7th January 13:07

[ant0276]

Be careful,

Unequal length links that are parralel have no instant centre only when they are exactly horizontal. As they move above and below horizontal, the I.C. moves from outside the wheel to inside the inner suspension pick ups infinitely quickly. This usually results in a really twitchy suspension response at this point of the travel. If you force an I.C to stay on the car side of a given wheel, all you need to worry about is the arc it follows as the suspention moves, and try to limit the roll centre migration. I usually try to keep them at about the height of the C.G. (but a bit under) assuming the car has a low one, to let me control the cornering weight shifts with a sway bar, rather than having to use the sway bar to control roll.

Cheers, and good luck