Ram Air a Myth...?
In the aerodynamics of a car, I would ask if the high and low pressure areas are due to the air being compressed or decompressed in those areas, or if what is being called pressure is really an effect of the collisions with more or less air molecules depending on the shape of the streamlines? In addition, there should be a boundary layer around the car for give or take an inch or so that moves along with the car, riding along with all the surfaces of the vehicle. The air outside the boundary layer is affected as the car moves through it. In fact by running into the air you impart energy to it and it also moves forward, but not at the same velocity as you are moving. Just like the wing above, this imparts drag on the car, and also creates a pocket behind the vehicle that can be utilized for drafting. To get to the point, air colliding with the windshield does not compress the air; it cannot because air cannot be compressed at this speed. Cowl induction isn't a bad way to get air into the motor though. It is a lot cooler air than drawing engine bay air, which is probably why the vents for the interior are in the cowl. And if the Bernoulli equation was 100% right, then when you drive through air that is sitting still and disturb it by imparting velocity, then all the air around the car would be low pressure.



