To sum it up, that screen mesh shit looks like a wall to air when you're going 60 mph. It hits it, builds up, and goes around. Very little will go through it. And the goal isn't to see how much air you can make flow around the heat exchangers, or how much air you can make blow around in the engine bay. You want to direct air through the heat exchangers, and duct things in such a way as to maximize the pressure differential across the heat exchangers as they are convectors. No pressure difference, no flow, no significant heat rejection. Bernoulli's equation says that if,you take air that has some velocity and SLOWLY and SMOOTHLY allow it to slow down and expand, it will compress.