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Good tip for intake case fans...

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mikren

Registered
Joined
Apr 5, 2001
I don't know about you guys but I found that my intake case fans where loud.
I also don't know how you guys have them mounted but mine where screwed right up against the case itself.
So I decided to fiddle around and took them off of the case and noticed they where extremely quite when not up against the case. So i didn't hesitate to glue 4 1/4 inch pieces of rubber extensions to each corner of the fans and glued them back to the case. Amazing how quite they now are and also have a huge increase in air flow. I mean "HUGE"

And the best part of it all...drop my temp by 1 degree.

This may be old news to most of you guys in here but I thought I'd share this experience with my fellow newbies.
 

outhouse

Senior Member
Joined
Mar 11, 2001
Location
Auburn California
Its good to post this topic because not everybody reads through ther tips section, i just made my delta a little more quiet by making a quarter inch silicone gasket for it [same principle as your method] and it works great anything to keep those vibration's from transfering into noise is fine in my books :)
 

cjtune

Member
Joined
Dec 18, 2000
I'm not sure how this is going to increase the airflow beyond what the opening for the fan can allow for...

However, it is true that rubber pads work as vibration isolators to stop fans from shaking the case as well but for me I found out most of the noise is from BLADE INTERFERENCE. This is what happens when you mount a fan so close/right up to the casing that a moving fan blade will stir up a loud turbulence when passing close to the casing surface. That's another reason why you ought to distance fans back a bit from their intended mounting places.
 

MIKREN @ work

New Member
Joined
Jul 4, 2001
The increased air flow is due to the fan not working as hard to get the air through the holes in the case when it up against it...try it out, put your fan up against the case and feel the air flow...then back it off from the case 1/4 inch...big difference :)

The flow is restricted to a direct draw when it has to come through the litles holes in the case.
 

outhouse

Senior Member
Joined
Mar 11, 2001
Location
Auburn California
I was wondering about that too good answer, on my case i cut out everything in front of my fans so there is no restriction what so ever helped allot, may be better then then just moving the fan foward.
 

Kingslayer

Senior Member
Joined
Jun 12, 2001
Location
Port Charlotte, Florida
The increased air flow is from less resistance, you're right on that point, but you are experienceing the less resistance because you are pulling more air from the gap you created by holding the fan off the case. You are effectively just recycling the air in your case, while cooling in MILDLY with incoming air from the holes. If you are going to do this, seal the whole fan, that way your aren't breaching your incoming air.
 
W

William

Guest
filled for use in the upcoming tips dbase, not the first time I have seen this, but I had forgotten about it, thanks for sharing!
 

inertia

Registered
Joined
May 24, 2001
I would think you'd lose the benefit of outside air quite rapidly. The fan creates a positive pressure on the blow side and a negative pressure on the suck side. Now you've made a hole through which these two potentials can interact.

For a 120mm fan a 1/4 inch (25.4 mm/inch *1/4inch= 6mm) gap creates a hole equal to 120mm long * 6 wide * 4 sides = 2880 square mm. The top of the fan is 120 * 120 = 14,400. That's at least 25% recycled air. Not cool.
 

Mad_Heckler

Registered
Joined
Jun 25, 2001
What about exhuast fans? What effect would using grommets or a spacer have? Would you get more air flowing out if, providing you didn't cut out the back of the case, and would it make it less lound?
 

Bad Maniac

Member
Joined
Jun 19, 2001
You do NOT want a space between the case and the fan, because as previously stated, because then the air just "recycles". The same goes for exhaust fans, if you back them up a few mm from the case with a rubber gasket to lower the noice, wich is very rewarding, you have to make a "skirt" to cover the gap between tha fan and the case. for info on this check the tips section.
And you want to keep the gap as small as possible, so that air is still allowed to circulate most efficiently, but allow for some rubber or silicone to prevent noice.

any other ideas out there?
 

Mord-Sith

Member
Joined
Apr 4, 2001
Ok this is what ive done I put small rubber grommets on the 4 bolts holding down my fan but then I also used doors sealand (that sponge strip stuff with tape on both sides) arround the fan. This gets you the best of both.
 
OP
M

mikren

Registered
Joined
Apr 5, 2001
That's probably and excelent idea. I have some 1/4 inch weather stripping sticky one side that I'll use to seal the gap.

I thought of the recycled air but I didn't think it would make much of a difference. Better yet I'll probably stick two layers thick around the fan and stick that back to the case. :)
 

Kingslayer

Senior Member
Joined
Jun 12, 2001
Location
Port Charlotte, Florida
Yes, 1/4" weatherstriping is perfect. It will give a good air tight seal, yet be "cushy" enhough to stop vibration and noise. It's also cheap. Superglue it to the fan.

One thing you have to remember is to have the fans sealed.

Another is to make sure that you enlarge (or totally cut out) the holes where the fan mounts. This will increase air flow, which in turn cuts resistance, which in turn quiets the noise. Those fans blow more air than those holes can provide.