Ducting

I have a few mods planed for the inside of my case! I'm looking for sugestions from people who have done similar things.

I want to know what is better: dubling the flow into the cpu HS or to add a draw to the side. I wish I could put a draw on the top because heat obviously rises but I have no more room than the width of a standard pencil.

Has anyone tried this before? Is it worth it?

If no one has tried I'll see what happens when I do it.

By putting another fan on the side dumping cool air straight into the cpu hsf I saw a drop of 8degC for my cpu, I've seen posts withanywhere from 2 to 10 degC drops this way. I also ran a duct to make sure the air went to the cpu first.

So I would be better off pushing air over my CPU HS rather than trying to draw the heat away?

Sniper ,Try cutting the fan grids out of your PSU.You will be amazed at the diff. it makes.Use a pair of aviation tin snips.
A dremel will throw metal dust into your PSU.Try this before you cut your case. THE FANMAN

I don't plan on doing any cutting. I have a 3 year warenty on this!

I'm just thinking about makeing ducts to run to the cpu HS.

Ducting ... out

I made a duct for my computer since I was tired of hearing the whine of the CPU fan.

The duct exhausts hot air directly from the CPU using the case fan.

At first with the duct I was using a generic heatsink, and standard clock, and no CPU fan, and overall everything was much quieter but at the expense of about 4C temp rise at the CPU.

When I wanted to overclock my Thunderbird 200 MHz to 1600 I got a better heatsink (Vantec Aeroflow) and decided to use the CPU fan included with the Aeroflow, a nice TMD fan.

Currently the CPU fan is running at 3100 RPM (full power would be 5500 RPM) and it is reversed (upside down) so that it draws air thru the heatsink and blows it into the duct, where the case fan helps blow it out.

I think that reversing the heatsink fan makes it *slightly* less efficient, but on the other hand, the case stays much cooler so the CPU can much better shed heat through the socket, so that's slightly better. All in all, I think it's a wash - the only real difference between ducting-in and ducting-out is that with ducting-out you don't dump CPU heat in the case and your case can stay much cooler without a lot of case fans going (I am using x2 80mm low-speed fans for intake.)

With this setup, 3200 RPM fan, under "normal" use (browsing, etc) the CPU temp is read as 47C and under 100% load it is read as 52C.

5500 RPM fan, at 100% CPU load CPU temp is read as 48C.

This is with the socket thermistor (no diode in Tbird) and Asus Probe, however accurate they are (not very.)

"Motherboard" temp (whatever that means) shows as about 2C above room temp. 24C at the moment - 75F.

In any event, I am overclocked, stable, and quiet.

I also discarded the chipset fan - this is only a 133 MHz chipset, so its not really necessary.

So, overall, using the duct for "exhaust" has worked fine for me.

I don't know how you'd get an exhaust duct around the base of the heatsink - that sounds like tricky placement.

Anyhow, I'd like to hear other opinions about reversing the heatsink fan to enable blowing CPU air directly out of the case.

By the way, Dell p4's sometimes have no CPU fan and just use a case duct over a rather large heatsink, suckng air out from the CPU ...

The wesson

Well, I had no intention on reversing the CPU fan but thought about accelarating the air from outside the case to the CPU fan or pulling exsaust out from the top or bottom of the CPU HS (which ever is more esily accessed).

MY PC

ducting ...

>I want to know what is better: dubling the flow into the cpu HS or to add a draw to the side. I wish I could put a draw on the top because heat obviously rises but I have no more room than the width of a standard pencil.

Taking a look at your picture:

Hard to make ducts to the side of the heatsink because the fins are going the wrong way. Awkward and no room. Any duct would be small and twisty, looks like, and this is bad for duct performance.

Turning around the exhaust fan and making a duct to dump air into the heatsink sounds good; drawback being that the (now intake) fan will bring in some warm air from the PS exhaust. Won't help case cooling at all, but will help CPU cooling quite a bit. If you do this, you'd have to reverse the intake fan as well, if you have one.

Looks like a perfect candidate to reverse the heatsink fan and use a duct so the case fan will help the heatsink fan & take hot heatsink air out.

Just try it. It's easily reversible. You might find good CPU cooling and much better case cooling.

By the way that case fan looks teeny. Is it high-RPM?

Maybe your best mod would be just to improve overall case airflow as much as possible. With very good case airflow, ducts are redundant.

The wesson

PS If you reverse the heatsink fan, you might get fan noise from the fan blades being too close to the heatsink fins (causing excess turbulence, etc.) In that case, have the heatsink fan stand on a little standoff made of cardboard or other material(with of course a big hole in it for the fan to blow through.)

Sometimes reversing the HS fan works better if you shroud the HS a bit. Your duct might do the shrouding for you.

In this case I have 2 case fans, 1 cpu fan, 1 PSU fan.

The case fan you see in that picture is the fan I was planing on reversing to pull more air into the CPU fan or to leave as is and pull the hot air out the bottom of the HS (maybe the top if I could get to it easily). The side panel fan is not an option here. I also have do idea what speed that fan is, yes it is smaller than 80mm, it also needs to be replaced because the bearings going out on it.

I have an degree in design so I think I could come up with a duct that can do what I want it to with little preformance loss either way I go.

OK.

Good duct luck, anyhow.

Duct URLs:
http://dansdata.com/chillvent.htm
http://www.dansdata.com/badong.htm

Or are you planning to do whatever people do with plastic to make your own plastic duct?

In any event, I'd be interested how it all works out for you.

the Wesson

Ok, Ill get to work on my prototypes and let you know how it works.

I did some pre-testing on my idea (with no duct) and came to the conclusion that I may just scrap the project.

Also I was working on this while my PC was running and I belive that I have more heat comeing off the GPU than from my CPU (Prime95 is always running in the background so my CPU is allways @ 100% use).

Sniper,You could take the PCI blanks top and bottom of Vcard out.
Place a fan in the A drive cage to blow the heat from the card out the back of the case.Or hang the fan from the A drive cage.For testing, you could use duct tape as double sided tape to attach the fan in a position you find worthy.I would also see about installing a large fan in the rear as a exhaust.Looks like you have room for 2 exh. in the rear.Next you need to see about getting some air into the front of the case.I cant see what you have in the front from the pic you provided.You may not have to do a single cut on your rig.Maybe drill some fan mount holes.Im sure you can design a bracket if you see that the mid-case fan takes care of your issue. My nickles worth, THE FANMAN

LINK

I included this link to give you some ideas of my work on cooling

Another fan in the back is imposible, Trying a card cooler fan right now. so far there is about only a 1C varience between running the card cooler fan vs. the noisy 60mm(thats in the process of dieing).

induction

Okay, then you oughta run a small duct from your GPU heatsink out and from your CPU and have them both exhaust out the back.

They'll both be happy having cooler air in the case since they're taking air from the case.

Your hard drives etc will be happier too.

theWesson

[edit]

I wouldn't expect you to see much change from reversing the exhaust fan. After all, you're just blowing the cool air in the general direction of the CPU.

You could try an 80mm fan in the case there using a 60-80 mm fan adapter -- if it fits in that space --

i think its good to have a blowhole for some reason the ducting doesnt look good to me thats just my oppion blow holes and side fans are sweet and do a good job to the looks on the duct kill it but perform good.

I've never heard of a 60-80mm fan adapter! I think a higher velocity card cooler fan above my GPU and a quiter variable speed 60mm exsust fans would work just as well.

The 60mm is currently unpluged(noise reasons), the bering is going out.

I also noted that my case temp with the side off is significantly higher than it is with it on: open case=42C+, closed case=33C(with all fans on). With the card cooler used in place of the 60mm it only goes up by 1C(low velocity fan).

almondboy72 said:

i think its good to have a blowhole for some reason the ducting doesnt look good to me thats just my oppion blow holes and side fans are sweet and do a good job to the looks on the duct kill it but perform good.

Click to expand...

A blow hole would be nice if I could find a top panel like that for my case, I have no intention on modding my exsisting one.

lol well i think u could find it just open the case and look for the top of it

Oh what am I looking for?

I know what it is I just want to find a different top to put on my case that has the blow hole already in it.