Case pressure for ducting

I have given up even trying to think of a decent way to get extra fans or whatnot onto my current case because it has an evil one piece top and it would be FAR too much modding to get it to work with any cooling on the side.

So i'm going to order a nice antec case soon. Now with this you get 2 fans included (80mm i guess). I then also have an extra 80mm fan and will bu a 90mm one.

So with this i was going to put an 80mm on the back exhaust and an 80 and a 90 on the intake at the front. I then intended to put a duct over the HSF so it can get some cool air.

However with ducts i have read that a negative air pressure in the case would be prefierable for better cooling, BUT i would prefer a positive pressure to keep dust out the system.

So overall would a negative air pressure be worth the cooling benefit rather than adding my spare fan on the duct and having a positive pressure?

Best way to find out for sure: experiment.

Even the general rules of thumb for case cooling have exceptions- to find what works best in YOUR case, you will need to try different things and monitor temps.

One thing that helps a lot: big, flat pieces of cardboard
Makes side panels, ducts and flow control vanes, as needed.

Once you do find the best arrangement for the case, you will also have the cardboard for use as a template for modding the metal panels.

Personally, I have found that slightly negative case ventilation does work more often then positive

best way to keep dust out is a filter

Stedeman said:

best way to keep dust out is a filter

Click to expand...

Just pop a K&N on there and wham! 10HP...oh, oh wait.

It depends on whether you have a passive duct or not. With a non passive duct, you'll have a fan at the entrance of the duct, so the case pressure is irrelevant. However, without a duct and strong positive pressure, hot air might escape the duct instead of going into it.

I run a passive duct with negative airflow. I have dust filters (pantyhose) on all intakes including the duct.

However, the best tip I can give you is....experiment!