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Increasing Fan RPM

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caincha

Member
Joined
Jul 24, 2003
Location
BRASIL
Increasing Fan RPM - PICS! ;)

Increasing Fan RPM


I had a Tt Dragon Orb w/ 68CFM @ 5800RPM and changed it for a Tt Volcano 9 w/ 75CFM @ 4800RPM.
I sure lowered my DBs noticeably but my temps lowered only about 3ºC... :bang head
So since noise ain't a issue I now want to increase my Volcano's RPM!
Can it be done? How? :shrug:
Is there anything else I can do to increase CFMs?
Thanks for any help.
 
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The only way to increase the RPM is to increase the voltage applied. Since it already runs at 12Volts, you can't easily do it with the existing power supply. It is possible to build a circuit that increases 12 Volts to something larger (voltage doubler circuits can do that), but circuits that do that are probably not as cheap as buying a different fan.

Finally, increasing the voltage on the fan will probably not increase the fan speed linearly ( that means doubling the voltage would probably not double the speed). And, there will be some voltage where the fan will burn out....bummer.
 
Is that so? Damn :bang head :bang head
What about incresing CFMs?
Perhaps making a few holes on the side of the fan...?
Would that increase CFMs...?
And what if I increase the amps...? More RPMs...?
 
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There is no easy way to improve that fan...none. It would be best just to swap it out for another fan you like. You might try ducting it, that may lower temps. You can either duct it from the outside, or use a gutted fan to act as a spacer. Decreasing case temps will also lower cpu temps.
 
caincha said:
Is that so? Damn :bang head :bang head
What about incresing CFMs?
Perhaps making a few holes on the side of the fan...?
Would that increase CFMs...?
And what if I increase the amps...? More RPMs...?
By reducing airflow resistance you might be able to improve it slightly, but you are really up against physics here. To reduce airflow resistance, remove any objects in the airpath to the fan. Clear out objects around where it comes out of the heatsink (if possible).
 
You could try replacing the ground line going to the fan with the -5v line form your PSU. That would run the fan at 17V. Your -5v line might not be able to deal with the power draw of your fan, and your fan might not run too well at that voltage, so I wouldn't recommend it.
 
Weird thing...
I had a Tt fan w/ broken blades (cleaning accident lol - I kinda fixed that though :p) that goes at 6200RPMs so I thought:
"Great, I'll change the fans' eletronic 'cores' and I'll get a Volcano w/ 6200RPMs!".
Nope!! :mad:

I did changed the eletronic "cores" of the fans but my Volcano only got from 4800RPMs to 5200RPMs! Damn, Damn!!! :temper:
The other one also got from 6200RPMs to 5200RPMs...
My temps droped another 2ºC (5ºC total) but I want to know why my "modded" Volcano can't go up to 6200RPMs?!?
Any guess..? Should I plug it directly to the PSU...?

BTW: the NB fan seems to sort of "follow" the CPU fan speed up or down...
When the CPU fan was stock at 4800RPMs the NB fan also was at 4800RPMs.
Now my CPU fan is modded and at 5200RPMs and the NB fan at 5200RPMs too.
Why is that? :confused:
 
caincha said:
BTW: the NB fan seems to sort of "follow" the CPU fan speed up or down...
When the CPU fan was stock at 4800RPMs the NB fan also was at 4800RPMs.
Now my CPU fan is modded and at 5200RPMs and the NB fan at 5200RPMs too.
Why is that? :confused:
It could be that your board does not actually monitor the NB fan speed, it just reports the CPU fan speed twice (or measures it twice and gets two slightly different values).
 
get a new fan thats not made by thermaltake, and since noise isnt an issue, get one of these insane beasts

Vantec Tornado 80mm Fan

Dimensions: 80x80x38mm
Weight: 175g
Rated Voltage: 12VDC
Power Consumption: 9.1W
Current Draw @12VDC: 0.76A
Rotation Speed: 5700RPM
Noise Level: 55.2dBA
Bearing: Double Ball

http://www.jab-tech.com/customer/product.php?productid=1494&cat=79&page=1


but just so you know, the only safe/easy way to increase a fans RPM is to run it at 13.8v, which requires a separate PSU so that you're not putting 13.8v into all of your other components as well

but for better cooling, you could also get a better heatsink such as an XP-90 or XP-120 (undisputed god of heatsinks), and mount a hella loud/fast/powerful Delta GHE 120mm fan on it
 
Bios24 said:
or use a gutted fan to act as a spacer.
I did that and only lowered temps in about 1ºC at best :/
What bothers me is why doesn't my fan reach 6200RPMs...?

Bios24 said:
Decreasing case temps will also lower cpu temps.
I'm working on that... But with 5 fans blowing in and 2 fans blowing out I'm kind of out of options here...

xTrEmEoVrClOcKr said:
Just buy a new fan, I dont think its worth the hassle :-/
There are a few reasons why not here are some:
1-I'm in Brasil and nothing here is cheap! For instance, this used Volcano 9 I bought cost me R$55,00 (brazilian money :p) which is about U$20.00!! A new Volcano 12 would be around R$150,00 (U$83.00)!!! And how much better is the V12 over the V9 anyway...?
2-Even if I had money to spend, I think I wouldn't... Only as the last resource maybe... I mean, what is the fun of just slaping a aftermarket fan (or cooler, or whatever) in you PC? Why not mess around and try to find a better, creative and cheap solution? :cool:

Gnufsh said:
You could try replacing the ground line going to the fan with the -5v line form your PSU. That would run the fan at 17V. Your -5v line might not be able to deal with the power draw of your fan, and your fan might not run too well at that voltage, so I wouldn't recommend it.
Well I tried this and guess what?! It toasted my fan!! So I wouldn´t recommend it either.Luckilly I was smart enough to try it on my old fan so no big harm done...




Anyway, I tried conecting directly to the PSU and even not knowing the RPMs, the temps actually were 2ºC higher...
Then I lubbed it up and RPMs got to 5600 and temps about 2ºC lower... But not steady, it varies from 5200RPMs to 5600RPMs.

I guess that's it, but I'm starting to doubt my temps readings...
As I mentioned before, I live in Brasil and right now we're in transition from a very hot summer to a somewhat cool autumn and since I can't say what are my room temps...
 
well, fans are made to spin a certain speed, and its near-impossible to raise that speed without raising the voltage given to the fan

and keep in mind that 6200 RPM takes A LOT of power to make happen on an 80mm fan... so basically what i'm saying is be happy with what you got
 
Sneaky said:
well, fans are made to spin a certain speed, and its near-impossible to raise that speed without raising the voltage given to the fan

and keep in mind that 6200 RPM takes A LOT of power to make happen on an 80mm fan... so basically what i'm saying is be happy with what you got
So it wouldn´t go 6200RPM because of it´s size... Now that makes sense, cause the other fan was 60mm...
 
Well I found this thread ( http://www.ocforums.com/showthread.php?t=375668 ) and there I came to this link ( http://www.afrotechmods.com/fanmod.htm ).
There I learned I was using the wrong wire and that's why I toasted my other fan... :rolleyes:

So, after I used the right wire it worked!!
For only about 30 seconds anyway, then the fan overheated and stopped... Bummer!! At least it didn't toasted too! :shrug:
So I modded it to compensate the extra amount of heat:

I opened up a hole below the core and glued w/ homemade thermal epoxy (regular "white goop" thermal paste + regular epoxy glue) a little hs in the tiny chip that was there.
You wouldn't believe how hot that tiny chip/hs would get without cooling!!
Then I opened 2 holes in the top of the blades' center to cool it's coils too.

Guess what?!! IT WORKED!!! Whoo Hoo!! :attn:
Here are a few pics:
CoolerCPU.jpg

OK, ok, I know this silver painting ain't as good as I thought would be, but at least is better than that strange-orange...

Anyway, MBM5 reads 7031RPMs tops which I think is accurate (high pitched hair dryer-like sound! :eek: ), but it also oscilates down to 6026RPMs and since there isn't a change in the fan noise I think it's steady at about 7000RPMs.
Since it's running about 45% faster, a educated guess will be that it's pushing about 110CFM which is about 45% more than it's stock 75CFM.

And now my mobo readings went insane so I don't think I can trust MBM5 temp readings anymore. I mean, it jumps from 45ºC to 58ºC in just 1 second!
Also, all the voltage readings are oscilating up and down too in about 0,06v all the time.
Judging from the other readings, I think it's at about 40ºC now (I guess is even lower, who knows-the hs used to get warm and now is actually cool to the touch!!) and that is at least 15ºC improvement overall!
MBM5 readings:
MBM5.jpg

And that's it, I'm done! I let it runnig overnight and no failures so far!
Just 1 question remains: should I be worried about that weird "side effect" that MBM5 shows...?
 
You may want to disconnect the rpm monitoring wire from your fan, as it's probably feeding weird voltages to your monitoring chip. You could also try adding a pot to the rpm monitoring wire, as described in the article I linked to. That might solve your sensor weirdness problems.
 
There is no end to the gadgets that OCers want to OC. :D If you work at it you may be able to make your PC fly!!! :D
 
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