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Case Fan, WHICH WAY? ? sucky sucky or blow blow??

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June 28, 2001 7:12:17 PM

I was scouting around Radio Shack and I saw this cool 12VDC Cooling Fan and I had to buy it. Look at the specs below:

<font color=blue>12VDC
Brushless
4.72" diameter (120mmx120mmx38mm), yes big and fat.
3000RPM
<b><font color=red>85 CFM airflow</b></font color=red>
Rated current: 320mA = 0.32Amp max
Rated power: 3.84 Watts max (I thought fans sucked allot of power, not so.)
Noise: 48dB max
Life Expectancy: 10,000 hours continuous</font color=blue>

<b>So which way should I direct the air flow, SUCKING OR BLOWING IN THE CASE?</b> If I have it sucking I can position it on the output from the HSF Alpha cooler for the cpu or I can direct the fan into the case at a lower section. Please let me know what you think and why. Thanks.

Note: this fan really pumps the air and is very quiet.
June 28, 2001 7:28:15 PM

Well for me, fresh intake air is more important.

I cut a special hole (not easily done) in the side of my case to direct intake air straight on the geforce (u love that) HSF.

Exhaust is important and I have an exhaust fan too (in the back), but it's not as important as intake because
there are other exits for air to get out of my case. And I've actually routed the airflow in my case with soundproofing material so exhaust is taken care of...
Getting the cool air in, that's the ticket - my opinion.

But if it's hard to get a clean entry hole for a fan that big???....you may want to just go the easy way and make it an exhaust fan. I've noticed that a fan without a clean
entry hole can create extra noise as well.

Let us know how the noise level of the fan is....I may pick one up myself.

I'm not in touch with my feeings, and I like it that way!<P ID="edit"><FONT SIZE=-1><EM>Edited by bud on 06/28/01 01:29 PM.</EM></FONT></P>
June 28, 2001 7:34:57 PM

It's 48dBa. Trust me, you'll notice it. Same as for a Delta 7k Black Label (like I have on my ThermoEngine).
I'm surprised it's that loud at 3000RPM, though.

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a b à CPUs
June 28, 2001 7:36:30 PM

I was thinking of mounting one on the bottom of my case drawing air from the space created by the feet. Since the power supply provides exhaust and I have an additional exhaust fan, this should be quite effective.

Cast not thine pearls before the swine
June 28, 2001 7:51:39 PM

Maybe, but you have to remember there's not much space under the box for air to sit. It won't cool properly, so you'll have heated air coming in. It'll still cool, but it's like using water cooling with room temperature water, or water with ice cubes in it.

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Apple? Macintosh? What are these strange words you speak?
June 28, 2001 7:56:36 PM

Mounting on the bottom is a good idea, I was going to mount it on the side panel. Which means I may have to reinforce the side panel if I do that. Basically what I was going to do is drill arond 100 holes in the panel (maybe case now) to make basically a grill for the fan. I've already ran the fan out in the open air and it is quiet, 48db is not very load, the airflow is massive. Compared to my Alpha HSF Turbo Prop Fan it is extremely quiet. Still not sure which way I should direct it. If I mount it on the bottom then I will have it blowing in, this would require me to remove my motherboard for drilling the many holes needed for proper air flow. Still which is better or maybe which is better if placed in different locations?
June 28, 2001 8:00:08 PM

Mounting on the bottom will require me to lift up the case sufficiently above my carpet for proper airflow. I would think 1/2" is more then sufficient in the Fan blows into the case.
June 28, 2001 8:05:59 PM

Remember, if you mount a sucky,sucky on the bottom (this is getting rude!), you might be sucking up all the dust and fluff from the floor area.

<b>
"Now drop your weapons or I'll kill him with this deadly jelly baby." :wink:
</b>
June 28, 2001 8:11:17 PM

Well I wasn't planning on using it as a vacuum cleaner (who said this is getting dirty?). Plus my place is relatively clean and the computer basically sits in the same place so this actually maybe a cleaner intake to have.
a b à CPUs
June 28, 2001 8:19:50 PM

Fans sucky sucky from the sides anyway, not from straight back, and I think that 1/2" of space would be adequate to provide necesary air. Heat rises, so I certainly would be drawing in cool air.

Cast not thine pearls before the swine
June 28, 2001 8:28:57 PM

I am really beginning to like the bottom idea and blowing, I can position the fan to blow on all the cards. I could use couch feet to raise my case up sufficently. I am sure raising the case up will be the least of my worries. Go figure, just after I dressed up all my cabling now I will dissassemble the computer for the drill.
Anonymous
a b à CPUs
June 28, 2001 9:24:19 PM

Well I find the best is if you have a draw from the from the front into the system (cool air going in) and a extra exauhst fan (I actually cut a hole in the back of my case at the same level as the CPU) so that there is a straight stream of cool air coming from the front to the back without getting heated from other components, I also have a fan in the regualr spot (bottom front of the case) to get the rest of the hardware.

Your probably asking how did I get a straight flow of air from the front to the back when there is no intake holes that are level with the CPU (I have a mid tower case and my 5.25 bays sit evenly with the CPU). I basically made one of my 5.25 bay covers (the plastic plates that fit in the slot when there is not device using the bay) look like swiss cheese in other words I beveled a bunch of holes where I attached 2 little fans side by side (about the size of Pentium/K6-2 heatsink fans) on the back side of the plate but if you want the easy way out go and get the Hard Drive cooler same idea (and it has a filter as well).

If you are wondering why I did it this way... well I'm a network administrator and have been for a couple of years and all the "special" server case that we have ever received are designed in the same maner... Air intake from the front and extra exaust fans on the back (the reason why the Power supply fan isn't enough is because the power supply gets hot enough as is and to add extra heat will give power inconsistencies) and on top of that you will see a big difference...

I used to keep my case open all the time and my temp sat around 40 to 45 degrees and with case closed it sat around 50 to 60 degress. With my current setup it now sits at 40 to 45 with the case closed and 35 to 40 with it open but unfortunaly that damn FOP38 fan is really loud and I really don't want the case open.
June 28, 2001 9:35:54 PM

Similar problem, the darn Alpha Turbo Prop is just to loud and I want my case closed. I am leaning towards the bottom idea from Crashman. If temp is still a problem then I will mount the same type of fan on top of the case blowing out. I really don't expect any problems though since this new fan really pumps out lots of air. I just have to make sure I don't have any signicant restrictions to air flow. The mombo 85CFM fan in addition to my regular pc case fan (85mm) also a dual Fan P/S setup should be enough. I may have to open up one of the drive bays to ensure no restriction for air coming out of the case. I will definitely have positive pressure inside the case.

I will do testing when project is complete and share the wealth of experience. Also thanks for the input.
<P ID="edit"><FONT SIZE=-1><EM>Edited by noko on 06/28/01 05:37 PM.</EM></FONT></P>
Anonymous
a b à CPUs
June 28, 2001 10:13:32 PM

85CFM airflow is bad for a 120x120!!!

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I am, you know I am. I am Canadian.
June 28, 2001 11:11:52 PM

It's from radioshack.

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Anonymous
a b à CPUs
June 28, 2001 11:28:31 PM

To drop in my two cents:

I use both intake and exhaust vents in any system that I set up. It just makes it easier to get the air flowing where you want it to go, with a slight emphasis on the intake fans. Plus I use removable, washable filters on all my intakes (also changing the whirrr of the fans to a somewhat more tolerable whhhsssss).

This causes an overpressure in the box, forcing air OUT through whatever cracks exist in the case instead of sucking infiltered air into the case. These cracks are primarily holes in the case itself, but are also the CD-ROM drive and the floppy drive. Have a negative pressure in the case will cause a tiny bit of air to be sucked in through the CD-ROM, pulling airborne dust particles with it to deposit it in the guts of your drives.

My system is set up as follows in an Aopen HX08 from low to high:

1 - 120mm intake fan in the front bezel down low
1 - 80mm exhaust fan in the back near the processor over the I/O port template.
1 - 80mm exhaust fan in the PS (which has grilles on the bottom to suck air from the case, through the PS and out the back)
2 - 80mm intake fans up high in the rear to blow directly onto 4 10k RPM SCSI drives
1 - 120mm chimney exhaust fan on top

I have a Tyan Tiger 133 MoBo with Dual PIII Slotties mounted with the stock CPU cooler cartridges, and these processors run about 5-10 degrees above ambient at near full load.
June 29, 2001 12:28:36 AM

question... how loud is that?
and where is your computer located relative to you?


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Anonymous
a b à CPUs
June 29, 2001 12:34:49 AM

Also, is that a full tower case or just a mid tower?

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I am, you know I am. I am Canadian.
June 29, 2001 1:18:27 AM

Alot has to do with the direction of air flow from your heat sink fan on your CPU. Does the alpha you have blow down on the heatsink or suck air off the heat sink? My favorite modification is to remowe the power supply and cut a hole in the bottom of it ( easily done with snips). Now with epoxy, glue the new case fan over the hole blowing into the power supply. seal all other vents in the power supply. Re-install the power supply and the fan should now rest directly above the CPU. You now have managed to effectively remove heat directly from the CPU and to help cool your power supply as well. What you now have is something akin to the enermax design.

A little bit of knowledge is a dangerous thing!
June 29, 2001 2:20:22 AM

Thats it? hehe.. j/k thats a little weak for
a 120mm though. I got a Nidec Beta V 120mm x 38mm
and it does 108cfm @ 46-48dba... I'm used to the noise.
My delta 92mm does 67cfm at the same dba. I bought
my friend a NMB 120mm x 38mm it does over 120cfm!!

Anyway, blow into the case.. at 38mm its probably too thick
to mount on the side panel, so put it bottom front of your
case and duct it all the way to the cpu.. that'll push
all the hot air away from the HSF and all the dust out of
your case.. its great to feel air coming out of every
nook and cranny! hehe... :smile:

Intel Components, AMD Components... all made in Taiwan!
June 29, 2001 3:38:41 AM

That sounds like an awesome setup. I will see how temperture does before I commit to more fans. I like the idea of the Fan on top plus ensuring that you have a positive pressure inside the case preventing dust from enter dirt sensitive components. That is a problem for my alpha, over a period of time the heatsink collects dust. Meaning the airflow will be reduced unless I clean it. What do you use as a filter? How often do you clean it or change it out? Thanks
June 29, 2001 4:14:53 AM

It is the typical suck from the sink setup which the Alpha uses. My case is different from yours, my power supply is not over the cpu. Which gives the cpu HSF breathing room. I've seen many cases where the cpu fan is almost right next or under the Power Supply resulting in temperture problems with the T-Bird due to the reduce air flow rate of the HSF. Now this is something I might try, the exhaust from the Alpha is the warmest source of air inside the case, if I direct that air out of the case then I would be transferring the heat from the cpu directly out into the atmosphere vice inside the case. I think that would work very good. The other fans would keep everything else cool and supply the volume of air which the Alpha is exhausting.

<A HREF="http://home.cfl.rr.com/noko/AlphaPS.jpg" target="_new">P/S and Alpha image</A>

As you can see the cpu HSF has plenty of room to breath and the air hits the side cover if installed. If I install a port from the side cover to the cpu HSF, I can isolate the most heat causing component in the computer by directing the hot air outside the case.

<P ID="edit"><FONT SIZE=-1><EM>Edited by noko on 06/29/01 01:32 AM.</EM></FONT></P>
June 29, 2001 5:07:29 AM

All right, maybe it is an under achieving 130mm Fan or the NMB/Nidec are exaggerating there claims, in any case how it works in the case is the real test. I do want something that is sort of quiet, I don't need to add to the Delta fan noise on the Alpha. Now if I port the air from the Alpha to outside the case I hope I don't make a megaphone for the Alpha.

<A HREF="http://home.cfl.rr.com/noko/RS130mmFan.jpg" target="_new">Perspective on Size, Bigger is better. . .</A>
July 1, 2001 1:45:24 AM

:smile: I havn't installed the 120mm fan but I did install the cpu exhaust port allowing the hot air from the cpu fan to be directed outside the case. The results are better then I expected. Running 3dMark2001 for 30 min with 100% cpu usage and case closed I got 45c cpu with a 25c system temperature. That is only 2c higher then with the case open. Here are some pictures to show what I mean:

<A HREF="http://home.cfl.rr.com/noko/Cpuexhport2.jpg" target="_new">Clear shot of case hole and CPU Alpha Fan</A>

<A HREF="http://home.cfl.rr.com/noko/Cpuexhport1.jpg" target="_new">How it looks when assembled</A>

I will probably install the 120mm fan shortly. The cpu exhaust port was very effective in keeping the case temperture inside cool without having any large intake fans. It just makes sense to exhaust the hot air from the cpu. I have one 3" intake fan which I paid $3.00 for at a computer show. Needless to say it really doesn't pump to much air into the case. Let me know what you think.

<P ID="edit"><FONT SIZE=-1><EM>Edited by noko on 06/30/01 10:10 PM.</EM></FONT></P>
Anonymous
a b à CPUs
July 1, 2001 2:02:27 AM

at least one for intake and at least one for exhaust.

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July 1, 2001 4:22:07 AM

Nice looking case, I have to tell you if you can the best way to keep the cpu cool is to dump the heat from the cpu out of the case. Mixing hot air and cool air gives you warm air inside the case. I will eventually install my 120mm fan after I do some more tests. I am planning to disconnect my only intake fan and just have the P/S and the cpu fan do all the cooling. I bet that I can keep my cpu less then 50c with a 30c atmosphere temperature. The cpu exhaust port blows out very warm air from the cpu keeping the temperture inside the case much cooler.
!