Quote Originally Posted by Malsor
khyberkitsune is correct. I'm going to use an elbow under my box and continue the ducting out my window. Should I use another elbow in my box to connect from fan to cooltube since its going to be a 90 degree angle or the ducting works fine? Also, since I'm using a 6" exhaust vent, what size should I cut out for my intake? I don't care for sound proof, I dont want bad pressure in my box.
Another elbow at the fan would be fine, or just plain ducting run along the ceiling. I've seen both done and both work.

For your hole. 6 inch exhaust, 4 inch intake hole. Guaranteed negative pressure and consistent.