Could depend couldn't it..... how much of it is shoved back out of the exhaust, do the valves open wide and for long enough for all of it to get into the combustion chamber in the first place, and can the routes that the air must travel flow the required amount in the time that the valve is open.

The engine sucks the air in through the carb, getting the air in is the really important part, which is why super/turbo charging is so damn effective!