haha, I was going to get into the fluid mechanics of the problem...

The air dam is a cool idea and theoretically should really help. It also doesn't have to be very big.

Air is not compressible at the velocities/conditions we are experiencing, so I don't believe the 3:1 ratio is scientifically founded. By increasing the outlet area you shouldn't get any more flow going through the inlet, and you can't draw out what hasn't gone in.