[ODE] Switching from Drawstuff to My own graphics engine

[smythst]

I've been playing around with ODE, and using Drawstuff for quick prototyping. 
However now the time has come to integrate my car physics into an already 
written graphics engine. Problem is I'm not exactly sure how to handle the sim 
loop myself. How should I call dWorldStep() - I mean how often, and where in 
my ode code. I've read that you should have a seperate ticker for your physics 
engine (from the graphics one) and that the physics ticker should be faster. 
Is this true, and why?

Cheers.