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Case Fans

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August 17, 2009 5:19:51 PM

Okay, for my new build, I will use my VERY OLD HP Pavilion a805n case. Since it only has one exhaust fan, there is NO intake whatsoever. So I plan to cut a 120mm circular hole on to the side panel so it can intake some cool air for the hard drive and graphics card. But my exhaust fan is only 92mm.

Will this be a problem at all? The 92mm fan moves air at about 43 CFM and the 120mm moves about 42 CFM.


Thanks. :hello: 

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August 17, 2009 5:37:55 PM

no it will be fine. be sure to debur the edges of your new hole so no one gets cut.

if a fan is rated for 43cfm in a straight tunnel it might flow 15cfm trying to pull air through the cracks in the case. now if the case had several intake fans creating a positive pressure within the case then the very same fan might push 66cfm.

Ideally you want the intakes low and the exhaust high
August 17, 2009 5:50:59 PM

Quote:
You can get a nice case with dust filters for $50 shipped, cmon, who wants a new build in a old HP pavilion case?

By the time you make the cuts, debur, sand, try to fit fans, etc, cmon man, more trouble than its worth.


I just might LOL. I could just go with the antec 300, but I hate to see something go to waste y'know?
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August 17, 2009 5:53:50 PM

505090 said:
Ideally you want the intakes low and the exhaust high


Exactly what I was thinking. Because cool air is always heavier than warm air, which in fact will sink to the bottom, warm on top.
a b ) Power supply
August 17, 2009 6:24:24 PM

+1 For getting a new case (the Antec 300 is a good one for cheap).

If you decide to mod your current case, you are on the right track.
Put the intake fan on the opposite side of the case from the exhaust and as low as you can get it.

You will need something like a dremmel or a 4.5 inch hole saw and a smaller drill bit for the mounting screws.
The best way to get the alignment is to first drill/cut the large hole, place a 120mm fan centerd over the hole and use a pen to mark where the mounting holes need to be.
Also, make sure to have some washers handy as you will probably have to open the mounting holes up a bit to tweak the alignment.
Make sure to be careful around the freshly cut areas as they will be very sharp.

I am sure it goes with out saying but make sure and empty your case out before drilling and be extra sure every shard of metal is cleaned out before putting it back together.
August 17, 2009 6:33:39 PM

outlw6669 said:
+1 For getting a new case (the Antec 300 is a good one for cheap).

If you decide to mod your current case, you are on the right track.
Put the intake fan on the opposite side of the case from the exhaust and as low as you can get it.

You will need something like a dremmel or a 4.5 inch hole saw and a smaller drill bit for the mounting screws.
The best way to get the alignment is to first drill/cut the large hole, place a 120mm fan centerd over the hole and use a pen to mark where the mounting holes need to be.
Also, make sure to have some washers handy as you will probably have to open the mounting holes up a bit to tweak the alignment.
Make sure to be careful around the freshly cut areas as they will be very sharp.

I am sure it goes with out saying but make sure and empty your case out before drilling and be extra sure every shard of metal is cleaned out before putting it back together.


o.0.... I guess drilling is fine... LOL I just hope the air pressure is correct so the fans don't kill each other lol. Gotta tell em to play nice XD
a b ) Power supply
August 17, 2009 6:36:25 PM

Do not worry to much about the air pressure, it will equalize it self.

If you are pushing to much in, it will leak from the cracks in the case.
This is good if you have the intake filtered as it will help prevent dust from getting in.

If you have more exhaust than intake, it will just suck the cracks in the case :D 
!