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funky 80mm adapter I've made

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toutin

Registered
Joined
Mar 25, 2001
I made myself an 80mm to 60mm adapter with two plexiglas squares and a kitchen funnel (idea from tril0byte) and I put on it a sunon 31 CFM rated at 25db to replace my sanyo denki 19cfm 28db on my pal6035...
My temps have increased a little (?) but my noise is reduced as well. But I thought those 31cfm would allow lower temps than my former Sd 19 CFM...
The sunon is set on sucking (as Alpha recommends it) and I was wondering if the higher distance between the fan and the fins is not the cause of that performance decrease (maybe intake is now too far from the fan? ) ? Maybe should I set the sunon blowing but PAL6035 is said to perform better on sucking isn't it? Any advices are welcome.
 

Liquid_N2

Member
Joined
Mar 6, 2001
Location
Essex, UK
The temperature increase is probably due to there not being as much area for the air to escape, your decreasing the area available and therefore temperature increases slightly.

Personally the PC can be as loud as it wants, as long as i know my stuff is nice and cold it doesn't matter, but everyone is different.

Just need to decide now whether the noise reduction is worth comprimissing the heat on the chip??

Run some test and let us know, maybe some more modification is required?? Maybe slots in the casing or some fans on the side (also make sure your using Artic Silver II heatsink paste) Or maybe water cooling is the answer??

Hope this helps.
 

Slake

Senior Member
Joined
Jan 12, 2001
Location
Knoxville,Tn
Thanks for sharing this info. It will help others when building their own adapters. I would try reversing the flow just for grins. Maybe you'll get better results. Keep us posted if you do.
 

sifu quoc

Member
Joined
Dec 17, 2000
i ran an 80mm adapter before too... it was quieter than my delta at 12 volts by a little bit... but the delta at 7 volts beats it at 12 volts... so i run my delta at 7 volts now... performs about the same as my 80 at 12 volts...

also much quieter
 
OP
T

toutin

Registered
Joined
Mar 25, 2001
So I tried (at last) with the Sunon 31CFM reversed (now it is blowing on the PAL) and it seems there 's no difference (maybe 1 or 2°C worse). I thought it would be better because sucking from a cone could lower total flow: Correct me if I'm wrong, the fan diameter is larger than the intake and therefore I thought It would have required more CFM to compensate the diameter difference so Blowing on it would add pressure (because of the cone) to air and make it colder (like blowing your mouth largely open make your breath warm and blowing with your mouth nearly closed make your breath cold). But the weather makes of any test a hell, it's rainy to shiny all the time (Belgium, Europe) even now in June. Any clue? I'll retest soon
 

Slain

Member
Joined
May 15, 2001
Location
Woking (near London) U.K.
Been said before but axial fans are *very* poor air at pushing air against any resistance. The faster and thicker the fan the more pressure it can produce. By forcing a slower rpm fan to push air through a fan adaptor and a sink you have probably reduced its cfm rating by half, probably more.
Even the Delta Ultra screamer which is 38mm thick and running at a mental 8000 rpm can only push air against the pressure of one inch of water.
 
OP
T

toutin

Registered
Joined
Mar 25, 2001
I just put the initial setting back , a nice 4 to 5°C difference actually...
It just confirms what you've been told Slain, thanks for the feedback.
My measurements were made using Prime 95 and UD agent and browsing the web.
For now, my adapter carries the fan set to suck air away from the PAL.
I think using the original denki now would provide 1 or 2 degrees less but I did this change for noise reduction so I'm half satisfied (I hoped better cooling for less noise and I only get less noise)... Maybe reducing the distance between the fins and the fan could help.