Mike Turner wrote:
> I reread my reply an it reads a little harsh. The
> theoretical limit is about 14psi and might be approached
> if the sumo is standing still and you can get a good seal
> between the skirts and the floor. While moving, you will
> have the equivalent of a negative hovercraft. The downward
> force will be small and directly proportional to the area
> under vacuum. Go for it. Good thinking outside the box.
> The group I autocross with has not figured out just how
> much traction you can gain using such an approach.
Because of the leakage, what is really important is not so much the pressure,
but the CFM (Cubic Feet per Minute) it can move. It has to be able to make up
for the leakage. A slow pump that can acheive perfect vacuum will be less
effective than say, a powerful Muffin fan with some kind of wastegate flap.
In fact, you'll probably WANT a small gap so that your vaccuum cup isn't
dragging on the foor, and all the downforce is on your wheels.