My memory is a bit fuzzy, but on the Spitfire airplanes "reverse ram air" was applied to the engine exhaust manifolds and a worthwhile gain in airspeed resulted.
It should be remembered that if two otherwise identical cars capable of 100+ mph terminal speeds in the quarter drag race repeatedly, with the two drivers swapping vehicles after each race, if one car gets fitted with an air intake that gets 2% gain from cooler air and 2% gain from ram air, you would expect that car to win more than 50% of ten or more races.