So what a PASSIVE INTAKE does is when the exhaust hole is bigger ( double the size perferibly ) then the intake hole it creates a NEGITIVE FLOW ( a breeze ) on the inside and will always make for fresh air intake. what works the charm is a 10 inch fan on the top instead of the computer fans . That will pum in crazy amount of air plus it has a speed regulator so u can ajust ur temps
by a few dergrees.