Originally Posted by headpunter
if the car was forced induction i could see it working because it would actively be sucking air in, but naturally aspirated no way that hole will allow enough flow.
I don't see how it couldn't have enough flow. The internal combustion engine is a glorified air pump. Think about it, we have a 6.2 liter engine (mind you, receiving all the air through a 90mm throttle body) , so every 2 rotations of the crank of the engine, 6.2 liters of air is getting pulled in and compressed, ignited, and released. So even at a somewhat low rpm of 4000 (where you might expect to see gains from a ram air anyways) the engine will be rotating ~67 times a second. divide that by 2, because every second rotation it will bring in 6.2 liters. You will be sucking in ~208 liters of air EVERY SECOND.
I would appreciate an engineer or someone to chime in and correct any wrongs. But, it's getting late I think I will leave the rest for tomorrow lol