One fan system...new Super-Duct photos.

Bluefront · Post by **Bluefront** » Sun Dec 21, 2003 3:04 pm

I've been playing around with the idea of using the 120mm fan in my Fortron PSU to cool the whole system, CPU and all. The prototype is up and running now. I'm using a P4 2.66 with an Alpha heatsink, a Radeon AIW 7500 and two Maxtor hard drives. There is a loose fitting duct from the PSU, so much of the exhaust air is being pulled through the alpha. Idle temp is about 33c and maximum temp using CPU burn is about 56c.

That max temp is a little high for me, so I think I should control the PSU fan manually, since it doesn't speed up as much as it should under heavy load, and the output temps from the PSU don't seem to go much higher when the CPU is under heavy load. Maybe a tighter fitting duct would help.

Some questions....What are the objections people around here have to a setup like this? This setup seems super quiet to me, but I don't recall many people trying it with a P4. A larger Zen heatsink designed for passive cooling, and a muffled exhaust system on the PSU would probably do the trick for me. Anybody doing anything similar?

dukla2000 · Post by **dukla2000** » Sun Dec 21, 2003 3:52 pm

No objections. The challenge is you are combining 3 needs (case airflow, cpu hs airflow & psu airflow) into 1 solution. The danger is 1 size will not fit all.

In theory a 120mm fan at 6V is pretty quiet and shifting 40cfm. Now 40cfm is plenty airflow for each of the needs and all the needs combined. Except by the time you duct that through a heatsink the static pressure will slug it to (my guess, based on some experiments/calculations but not gospel science!) well under 20cfm which is getting marginal.

Then again, the FSP may get upset with preheated P4 air and raise the volts to the fan - 1 size starts getting tight.

And if you dont have a nice case airflow those Maxtors could be warmer than I would like.

Certainly I am running a 2 fan PC as I type, and 1 fan is (acoustically) possibly preferable. So try and see how far you can get. My problem is I can virtually silence my psu/case fannage, but my Athlon (2400XP equivalent, Folding 24/7) needs more air than I can find a (very) quiet way of providing.

Bluefront · Post by **Bluefront** » Sun Dec 21, 2003 4:40 pm

Well I've used similar ducted setups successfully before, but never tried doing it with one fan. I'll probably ditch one maxtor, so that'll remove one heat source. The remaining drive will sit in the airflow from the one case opening, so it should be ok. I monitor every hot spot with a DD5, so I know what's happening temp-wise.

I don't run wide open all the time, but some things I do are intensive. I use an A-Open board with SilentTek, so I can hook up aux fans that turn on at high temps. I sure do like the sound of this setup with only one fan going....it's quiet.

pingu666 · Post by **pingu666** » Sun Dec 21, 2003 6:41 pm

my worry would be the hds
ive used just the psu fan on my via, it got toasty
but its a undervolted papst, 7cfm or sumin i guesstimated

Bluefront · Post by **Bluefront** » Sun Dec 21, 2003 7:01 pm

Here's what the hard drive setup looks like.....sits right over the filtered intake hole. It has a copper frame mount and runs pretty cool. It'll be ok.

Zyzzyx · Post by **Zyzzyx** » Sun Dec 21, 2003 7:15 pm

Ya got me curious now, Bluefront. How many hours/week do you spend tinkering and building on your systems?

And I think some folks might be thinking that you're using an external duct to feed air to the CPU cooler. I remember from your previous photos (and you might want to reiterate) that you're drawing case air over the CPU cooler into the PSU. Using the single filtered intake pictured to cool the HD.

Bluefront · Post by **Bluefront** » Sun Dec 21, 2003 7:46 pm

Heh, one of these days I'll get it right. It does take too much time, but it keeps me out of the bars.....

This latest project replaces my retired Lanboy setup. Funny I got this case at a computer show, and it sat in the basement for a year. It turned out to be perfect for the project....don't even know what brand it is.

Bluefront · Post by **Bluefront** » Mon Dec 22, 2003 3:21 pm

So far, so good. I added two small 60mm fans to the exhaust duct....they only turn on with high usage (cpuburn), so with anything I'll do, this computer will run off the 120mm Fortron PSU fan only.

Temp results with 22c ambient

Idle temps

cpu.....................34c
System...............33c
H/D....................37c
PSU output..........28.5c@1592rpm

Max running CPUburn

CPU.....................52c
System................35c
H/D.....................38c
PSU output...........32.5@1786rpm

I'm still working on an external muffler for the PSU, and a muffler for the intake, so I don't have any pics yet. This is a neat, quiet setup. The duct that enables this setup is made out of a plastic cap that covered an auto distributor. Wouldn't know it by looking at it anymore. Heh. Might get it finished with pics over the holidays......

I am somewhat disappointed with the PSU fan....it seems to vary rpm for no particular reason. Wierd. I guess I'll have to mod the PSU fan, and let SilentTec control the speed using the CPU temp. Should work ok, but I might have to find a different 120mm fan....

Bluefront · Post by **Bluefront** » Thu Dec 25, 2003 10:20 am

I posted some new pictures of my Super-Duct

.

As I said, it's made out of a Nissan distributor cap cover, and held on to the case with one small bracket screwed into the case. It is not attached to the PSU, but is held against it by the bracket and a foam seal. You can remove it quickly with three screws.

The Alpha heatsink under it is not visable, but it has no fan on it, cooled only by the Fortron 120mm fan. The two 60mm fans you can see only turn on when the temps approach 50c. I have only got these fans to turn on running CPUBurn. So the setup usually is very quiet.

All the intake air is coming through the one filter you can see under the hard drive. The drive temp is usually under 38c.

I applied a few new stealth techniques to the power cables.....you can see them in the photo with the hard drive. Basically I routed the cables behind the insulation panel. There's two connectors sticking out for further expansion.

I'm still working on this new setup...more pics to come.