I could try a backward facing scoop. That way I wouldn't get any dirt/water in my engine bay. Of course it wouldn't shovel air in the engine compartment but it might not matter as the backward facing scoop would provide a way for the hot air to escape when fresh air from the grill area pushes the hot air out.

Although it would look horrible I'm also thinking about some sort of heatshield over my headers to act as an air guide. the fan would push the hot air from the headers out of the engine bay from underneath the car.

or I could just buy ceramic coated headers