[Pleiades]

Hi, does anyone use a fan adapter to put a bigger fan onto their heatsink? Reason I ask is I have an Akasa Silver Mountain from years ago with a humoungously noisy Delta screamer (6800 rpm!) 60mm on top... I removed the latter and put on an Akasa 80mm (from an Akasa 827 HSF I think). Just wondered though if the air gap (about 25mm) caused by the adapter between fan + heatsink is detrimental to cooling effect...

On similar note, could you use such an adaptor to put say, a 120mm fan on an Sp-97 HS and would it make much difference either way?

 

[Burn]

nope, as long as you go from a smaller fan into a larger surface area... like a 80 to 92 mm adapter, it actually helps cuz it spreads out the dead spot created by the fan motor... if you go the other way however, from 120 to 90, it doesn't help...at all...it creates backpressure.

 

[Bindusar]

Whether you go bigger or smaller, the real issue is the CFM. As long as the CFM is equal to or greater than the fan being replaced you are good to go. Typically your larger fan will have a lower RPM and thus lower db but yet move more air. With the throughputs and pressures we are talking, increased CFM through the same opening will result in faster air, but it isn't enough to cause laminar flow and in turn cause insulation instead of heat exchange. I am doing the same thing in a few days when my 80-120 adapter from coolguys shows up...putting a 120 on my not so cool Aerocool copper heatsink since I have the fan laying around.

 

[Pleiades]

Thanks guys for your informative comments, I will need to look up 'laminar flow' tho... Very much appreciate your input; tell us how u get on with that monster fan Bindusar.

 

[Ket]

if anything the slight gap will help with cooling the CPU, its like if u place a fan against something with no holes, no holes = no air, then you take that fan away from what its resting against and place your hand a little behind the fan, more air.

 

[Burn]

well, also because you are eliminating further the dead spot created by the fan motor. no fan blade=no air flow...

 

[Ket]

thats what i said, i just made it easy for the guy to understand

 

[Burn]

i see. i thought that you were talking about not airflow coming from the fact that there wasn't anywehre the air can be drawn from, not a dead spot where the motor is... you said: "its like if u place a fan against something with no holes, no holes = no air" i don't think it talks about a dead spot at all... not to be arrogant or anythign, i'm just pointing something out.

 

[Pleiades]

While we're on the subject of mahousive fans, how about if I put an 80 to 120mm adapter on top of the 60 to 80 one and added something like this: http://www.overclockers.co.uk/acatal...a_Fans_58.html (scroll to bottom of page, tried the link to specs but it didn't work).

The air gap would now be approx 50mm, whaddya reckon?

 

[Bindusar]

59 dBa??!!??!!??!!

You could hear that in the garage...with the car running!

Now, what do you mean scroll top to bottom, are you looking to put a fan at each junction? If so don't do it if you are planning on that screamer of a 120. Since the other fans can't move the volume of air that the 120 can, they will just slow it down and cause backpressure.

Oops, just re-read your post...you just want the single 120. The distance is fine, it won't hurt anything. Is the HS it is going on sized for a 60?? Seems small. There would be no benefit to waisting it down to 60. The pressure would go up a bit which means the fan might not hit max RPM. The only other thing that happens is the air would have a higher velocity coming out the 60mm opening.

 

[Pleiades]

Hi Bindusar, wow that was a quick reply, was really half in jest (but I'm tempted as I am an inveterate fiddler of PC bits, the large pile of discarded dead ones is testament to that).

I c what u mean about putting a fan at each junction, as u rightly stated it wasn't what I originally meant, though it actually sounds like a fascinating exercise But pointless of course due to what u said about back pressure... :-(

Yeah the HS is only lickle, though a good old one, all copper + plated with silver.

 

[Burn]

RE: spacing the fan (i think you're trying to do that)... you know what a throttle body spacer is? it goes in between your carb and your intake manifold... i think... it provides more space for fuel/air to go through, and you can apply that same scenario to this... just make a spacer that's an inch in thickness, and attach it w/ longer screws/bolts/w/e you use... i think that' swhat youre trying to say...i believe..lol
Quote:

Originally Posted by Pleiades Hi Bindusar, wow that was a quick reply, was really half in jest (but I'm tempted as I am an inveterate fiddler of PC bits, the large pile of discarded dead ones is testament to that). I c what u mean about putting a fan at each junction, as u rightly stated it wasn't what I originally meant, though it actually sounds like a fascinating exercise But pointless of course due to what u said about back pressure... :-( Yeah the HS is only lickle, though a good old one, all copper + plated with silver.

 

[Evil XP2400]

Quote:

Originally Posted by ATVkid*AFZ* RE: spacing the fan (i think you're trying to do that)... you know what a throttle body spacer is? it goes in between your carb and your intake manifold... i think... it provides more space for fuel/air to go through, and you can apply that same scenario to this... just make a spacer that's an inch in thickness, and attach it w/ longer screws/bolts/w/e you use... i think that' swhat youre trying to say...i believe..lol

Well for that kind of spacer you can use another fan of the same size and gut it (cut the blade part out) it would work as a shroud and help eliminate that dead spot.

 

[Burn]

Quote:

Originally Posted by Evil XP2400 Well for that kind of spacer you can use another fan of the same size and gut it (cut the blade part out) it would work as a shroud and help eliminate that dead spot.

yeah, eliminates a lotta cutting/forming, and it's easy too... just remember to get a POS fan to gut..lol