[diesel_john]

my take on the perforated sheet metal grill is yes it will work but round holes are a very inefficient way to duct in air.
We might pushing a lot of air around all the time when we don't need it.
If we divert all the air with a smooth airfoil and then have an NACA intake duct that opens only as much as we need, it would only induce extra drag when we need lots of air instead of all the time. does that make sense.
note the shape of the intakes on the hood of this red car.