Now how gay would it be for me to be asking that? And worse you actually came in here. I am talking about your fan shroud. I am going to make one tomorrow and I want to know how many inchs I should make the space between the fan and the rad. 1, 1.5, 2 and what diff does it make?

At least an inch. The farther away, the less of a dead spot there is.

Mine is 9 inches personally.

It depends most upon the size of the center hub. If the center hub is 2 inches across, it will generally perform great when placed 2 inches away. If the hub is an inch and a half, place it 1.5 inches away from the rad.

It's not just the hub that is impeding air flow, but the radiator itself. A shroud of about 3 inches will double the air flow of a typical fan through a radiator. I can't seem to find my performance curve charts, I'll look more later. But, the further a fan is lifted from the resistance the greater the performance.

Basically anything over 3/4" will dramatically improve air flow through a radiator. Anything much over 3" won't gain you much. Design between those to your size constaints and you should be okay.

Also the type of fan you use can make a difference. Fans such as Pabst with a planar air flow (the air flow is perpendicular to the fan body or straight out) have proven to be less efficent than Axial fans which deliver air flow in a funnel pattern.

And 38 mm fans with the same cfm rating as a 25 mm fan generally has a higher pressure rating. So when there is more resistance they move more air than the 25's.

The fans actually are papst fans but they are going to be moved to the case sides and I will be replacing them with sunon fans as I like their sound the best and the ability to turn them up for better cooling is a bonus. So then from the sound of it more is better but more than 3 is unnecceary?

Quote: Originally Posted by psychofunk The fans actually are papst fans but they are going to be moved to the case sides and I will be replacing them with sunon fans as I like their sound the best and the ability to turn them up for better cooling is a bonus. So then from the sound of it more is better but more than 3 is unnecceary?

See for yourself, the added return on anything over 3" is very slight in the typical fan.

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Okay now I am confused...damn charts...no really okay so then should I make my shroud 2.5 or 3 inchs?

lol...ignore the pressure scale and concentrate on the bottom figures. 2 and a half would be more than sufficient. Most premade shrouds aren't even that deep.

So then how much of a loss would I have if I opted for 2 instead of 2.5? And will having the system in a push/pull affect this space? Is there a difference between having the setup as a push only as opposed to a pull only?