Looking at the pressure over a car's body; the lowest pressure is the front of the roof.
(Easy to see where a radiator vent should exit too)
So here's a crazy A-Pillar Vent idea and questions:
Why not use the hollow A pillars to vent the engine bay (some) up to vents in the front of the roof?
If the vents are properly designed aerodynamically, wouldn't that suck some of the air out of the engine bay, reducing flow and pressure under the car and reducing lift and drag? over the car?
The roof vents would have to be properly aerodynamically designed and the ducts water tight and able to drain.
I have no idea what the ducts would look like for best aero??
There are plenty of aftermarket roof and hood scoops but I'm guessing that properly placed, sized and shaped slots in the roof, with a similarly well designed vent under the roof..?
aerohead?