[ODE] problems with hinge2 & car steering

[Sergio Valverde]

Hi,
I'm coding a simple vehicle simulation with Hinge2 joints (yes, 
yet another buggy-derivated driving model)  but I'have problems 
trying to keep the car stable when turning.  The wheels are 
simulated with single spheres which are connected to the body 
with the hinge2's. 

When the car si moving straight seems to work ok but if turning 
and accelerating at the same time chances to overturn the car 
are increasing very fast!!  Also, seems that turning the car
has the undesirable effect of brake it, making very difficult to 
drive the car.

I tryed to adjust both the Erp & Cfm suspension parameters and 
even the masses of body and individual wheels but the desired 
behaviour was not reached at all. 

Any idea to fix this awful behaviour?
Thank you very much,
Sergi