Sign in with
Sign up | Sign in
Your question

Fan adaptor

Last response: in Overclocking
Share
December 30, 2002 6:38:16 PM

I saw a review recently(can not remember where) and it showed that a 60mm fan at like 30 cfm could cool a heatsink better than an adaptor and a 80mm putting out like 50 cfm. Why??? The reason I ask is because I am wanting to buy the Arkua 7228 heatsink and put a 80mm fan on it using an adaptor. Now the fan I want is a Aerocool 80mm that puts out 51.5 cfm at 31 dba(good numbers). Now in my simple mind(I am an engineer by the way) I see no reason why it will not cool even better(slightly) than the orginal 60mm putting out 38.4 cfm at a whopping 46.7 dba. Now am I wrong??? or just lost?????

More about : fan adaptor

December 30, 2002 8:35:02 PM

My simple mind can't accept it, too :) , although the adaptor take away the fan from the radiator the loss should be minimal.
I read somewehere here about using a grill trick to attach larger fan to a smaller heatsink. Very fresh...
Why don't you just buy a larger heatsink and be happy ;) 

:wink: <font color=green> The second time is always better than the first :wink: </font color=green>
December 31, 2002 9:32:44 AM

I don't get it too... but my guess is that it is because the adapter has a bad aiflow, which with the dead spot in the fan reduces cfm badly.

My PC eats so much money that I'm in 'desperate' need of it to buy PC3500 RAM, help Svol with his OC project!
--- PM me for information.
Related resources
January 2, 2003 3:28:20 AM

The probable reason is that fan adaptors arnt very efficient, they are too shallow, and much of the airflow is squandered with turbulance, the dead spot beneath the fan hub and backpressure.

Adaptors need to be made much deeper and more aerodynamic to be really effective.

<b><font color=purple>[Rik_]</font color=purple> I wonder how many people have made their own phasechange system?
<font color=blue>[LHGPooBaa]</font color=blue> I get phasechange whenever i eat a hot chillie :lol:  </b>
January 3, 2003 4:02:39 PM

I wouldn't think it would be because of the dead spot under the fan core.

Anyway... here are my two cents.

There is probably less CFM from optimal due to the compression of the air while going into the smaller opening. The fan blades would have to force the air harder but they are still spinning at the same speed. Since there is increase resistance the blades probably slow down to some degree.

The other part of any loss would then be due to some air being forced out other openings. I have one adapter that is metal. There are blades that are pinched together. There are gaps inbetween where they come together. Others, the plastic ones, seem to have vents at the base of where the air is funneled.

So due to whatever reasons or comination of reason it is not outside the rhelm of probability or practicality. I have never liked them.

<b><font color=red>Fredi</font color=red> <font color=red>Fredi</font color=red> He's our man! If he can't do it no one can!</b><P ID="edit"><FONT SIZE=-1><EM>Edited by Bum_JCRules on 01/14/03 11:09 PM.</EM></FONT></P>
January 3, 2003 4:24:08 PM

Visuals...

<A HREF="http://www.casecooler.com/80to60clearp.html" target="_new">Akasa plastic fan adapter funnel.</A>

Now the slots on the sides make no sense. If they are trying to channel the air towards the heatsink... why would they cut sides in the funnel? It wouls be better to use the 2CoolTek grill method or this little <A HREF="http://www.extremeoverclocking.com/reviews/cooling/Amuz..." target="_new">toy I found</A>. (I like the <A HREF="http://www.2cooltek.com/retro.html" target="_new">grill better</A>.)

<b><font color=red>Fredi</font color=red> <font color=red>Fredi</font color=red> He's our man! If he can't do it no one can!</b><P ID="edit"><FONT SIZE=-1><EM>Edited by Bum_JCRules on 01/14/03 11:09 PM.</EM></FONT></P>
January 3, 2003 4:28:51 PM

How about this <A HREF="http://www.xxlcases.nl/shop/docs/pd1026588150.htm" target="_new">one</A>.

No holes at all!

My PC eats so much money that I'm in 'desperate' need of it to buy PC3500 RAM, help Svol with his OC project!
--- PM me for information.
January 3, 2003 6:05:42 PM

I have never used one of those. I haven't tested one yet. I am sure there would still be some form of increased pressure back on the fan blades and loss in CFM from optimal.

I am sure you would still need to use a fan that moves more CFM than the one it is replacing. (To ensure enough CFM on the exhaust side of the funnel.)


Poobaa... you ever use one and test the temps?

<b><font color=red>Fredi</font color=red> <font color=red>Fredi</font color=red> He's our man! If he can't do it no one can!</b><P ID="edit"><FONT SIZE=-1><EM>Edited by Bum_JCRules on 01/14/03 11:09 PM.</EM></FONT></P>
Anonymous
a b K Overclocking
January 3, 2003 6:44:57 PM

"There is probably less CFM from optimal due to the compression of the air while going into the smaller opening."

Yes, this is the case. I am looking at a datasheet for a densitron fan motor right now (DPF25A). There is a graph which shows this relationship for this fan. Basically for each pressure there is a corresponding air flow. It is not a linear relationship like a person might guess (not really sure what type of curve that is). I wish I could find nice complete data sheets like this for all the different fans, then it would be easier to use them.
Anonymous
a b K Overclocking
January 3, 2003 6:45:55 PM

look at me, I'm an old hand.
January 3, 2003 10:57:29 PM

ive played around with one and the airflow loss is considerable. It would however be better if the ctandard casefan could cope with backpressure better, and the adaptor was longer and more tapered.

with any particular 120mm fan the airflow loss can be as bad as 50%.

<b>Pentium4 Celleron: The computing worlds Rice Car.</b>
January 4, 2003 9:20:01 AM

And that was a fan adaptor similair to the one I posted?

My PC eats so much money that I'm in 'desperate' need of it to buy PC3500 RAM, help Svol with his OC project!
--- PM me for information.
January 4, 2003 7:13:13 PM

I just had a thought on how to raise the efficency. What if a shrowd was added to the top adound the sides of the fan? Basically this would be something to extend the sides of the fan walls up vertically. The blowback would be recycled or minimized to some degree.

It might help and maybe not... I haven't tried it yet. I don't have the time not to try it. I just got two more machines to hack and salvage parts from.

<b><font color=red>Fredi</font color=red> <font color=red>Fredi</font color=red> He's our man! If he can't do it no one can!</b><P ID="edit"><FONT SIZE=-1><EM>Edited by Bum_JCRules on 01/14/03 11:01 PM.</EM></FONT></P>
January 5, 2003 4:23:57 AM

Possibly...
In my experience the amount of flowback between the fan blades and shroud it determined by:
A. fan blade shape
B. size of gap between blade tips and the shroud
and
C. backpressure.

a better way would be to have the fantips all joined together in a circle of plastic, like they do with some marine propellors, but taht would add significant weight to the fan assembly and would ened more current to spin.

Still waiting for someone to design a better and deeper fan adaptor *taps fingers*

<b>Pentium4 Celleron: The computing worlds Rice Car.</b>
January 5, 2003 11:08:42 AM

Well it is a lot shorter then the one I posted (although that is only a 80mm to 60mm one) and it isn't very aerodynamic.

My PC eats so much money that I'm in 'desperate' need of it to buy PC3500 RAM, help Svol with his OC project!
--- PM me for information.
January 6, 2003 12:01:41 AM

you could design aerodynamic adaptors and make millions :smile:

<b>Pentium4 Celleron: The computing worlds Rice Car.</b>
January 6, 2003 4:45:19 PM

LOL... for those few people that want to use them?

My PC eats so much money that I'm in 'desperate' need of it to buy PC3500 RAM, help Svol with his OC project!
--- PM me for information.
January 6, 2003 8:42:56 PM

Well ill buy one!

<b><i>The Very Hungry Caterpillar</i> - George W. Bush's favorite childhood book.
Note: This book was first published a year after Mr Bush graduated from College.</b>
January 7, 2003 3:52:58 PM

That one looks nice indeed.

My PC eats so much money that I'm in 'desperate' need of it to buy PC3500 RAM, help Svol with his OC project!
--- PM me for information.
!