My Ducting - excellent results

jaypers · Post by **jaypers** » Wed Feb 12, 2003 9:56 am

I know there's been a few posts about this but I thought I'd run my own with my own findings. I've been unhappy for several months about how unefficient my CPU fan and case extract fan setup were. I have an Asus A7V333 Mobo, XP2000 with Zalman flower heatsink, bracket & 92mm fan; I use a Ultrasilent S2 c29cfm case extract fan.

I noticed when running CPU burn that the case extract fan was hardly blowing out any hot air despite being at full power and that my Seasonic SS-300 PSU was blowin out flames (ok I'm exaggerating but the air was HOT). I concluded the hot air from the heatsink is dispersed by the Zalman rendering the case fan quite ineffective - If I removed the case fan, the temps would only rise by a few degrees (4-5).

I built an ugly looking (not a problem for me) duct out of plastic cardboard. It fits snuggly around my Zalman HS - 1mm clearance on the sides and 1cm shorter than the lenght of the Zalman (ie it fits completely over the Zalman & the air gets sucked up from the bottom centre and outwards across the 'petals'). This duct goes straight to the 80mm extract fan and I fully removed the Zalman bracket and 92mm fan.

Well it works a treat

my setup is not only more efficent but much quieter. Here are my results:

2 Fans @ 100% Temps: Idle=59 Stressed=70 Seasonic fan blowing hard & hot
1 Ducted fan @100% Temps: Idle=51 Stressed=67 Seasonic fan @ say 40% through its range

I tested the duct blowing inwards and achieved improvement in CPU temperatures of 3-4 degrees. My Mobo and HDD temps however went up by 5-6 degrees and the Seasonic fan went like crazy again. The extract option seems better to me. I have no other intake or extract fans on my case.

Hope this is of help to someone, I'd be interested in any comments...

jp

PS BTW I don't use that fan @100% all the time, I use Speedfan!

snowmoon · Post by **snowmoon** » Wed Feb 12, 2003 10:03 am

A pic is worth 1k words.... any chance we can take a peek?

ez2remember · Post by **ez2remember** » Wed Feb 12, 2003 2:54 pm

I could not agree with you more, I also mentioned about this in another post on a slightly different note. The rear exhaust fan is not very effective where it is positioned in most cases. Hot air rises so naturally hot air will get sucked up through the grill cut out of your PSU. The exhaust fan position is too low down.

Well done on your achievement, kinda fun the more you discover and the more mods you do.

But the reward, is a quieter more peaceful computer..

Mark Larson · Post by **Mark Larson** » Wed Feb 12, 2003 6:02 pm

I've had excellent results with ducting

Not the kind you're talking about, but man did it lower my temps. I also didn't need a single case fan and could turn down the Enermax on my AX-7 down to ~2100rpm. The most annoying source of noise was the Maxtor D540X however - loud as heck and a constant whine, like a 60mm fan, only whinier.

Syphon869 · Post by **Syphon869** » Wed Feb 12, 2003 11:34 pm

What is that? An air conditioning duct?

And hey! You got the same case as me!

As for your hard drive problem: Go get a Seagate. Cold and silent.

jaypers · Post by **jaypers** » Thu Feb 13, 2003 1:53 am

Mark - the seal looks like a pair of ladies tights, what happens if your wife/girlfriend needs them back!?

Snowmoon - I know what you mean, I wish I could put a picture up. Sadly I don't have a digital camera or scanner

.... I'll see if I can borrow one.

I've done some further testing using Speedfan:
2 Fans: PC+fans idling Temp=63 -> Loss of 4 degrees over 100% fan
1 Ducted fan PC+fan idling Temp 58 ->Loss of 7 degrees over 100% fan

Interestingly, the system is relatively silent with united devices on as the fan only needs to run at around 1/3 speed -> 65 degrees. With CPU Burn for AMD, which I think is the ultimate test, I get 67 degrees with a noisy fan at 100%. The 2 fan setup needed all fans to be at 100% for united devices.

By the way, my method of getting a temp is leaving the computer in a setting for 15 minutes so temps stabilize. Also, my definition of "idling" for a fan is basically it just managing to restart safely/comfortably after you stop it physically (finger!).

Enough boring stats, I'll try and get a picture!

jinu117 · Post by **jinu117** » Thu Feb 13, 2003 1:31 pm

I'd really like to see picture now. I use Zalman 5700 cooler which has same idea of duct thing which I found to be extremely good at keeping temp down. However, I would like even better heat sink in combination with the duct. (Problem is, I might have hard time utilizing the duct with SLK-900 from its design) It would be interesting if I can use one of the best cooler available at extremely low speed fan and some ducting for my system. (I might actually get to all fans running at 5v than)

Mark Larson · Post by **Mark Larson** » Thu Feb 13, 2003 1:33 pm

Syphon869 wrote:What is that? An air conditioning duct?

It comes in from the window - check my location

And hey! You got the same case as me!

It totally rules - amazing for the money. Only thing i wish for is a removeable motherboard tray.

As for your hard drive problem: Go get a Seagate. Cold and silent.

Done

It should be here today or tomorrow.

jaypers wrote:Mark - the seal looks like a pair of ladies tights, what happens if your wife/girlfriend needs them back!?

She goes without!

Actually its just an old T-shirt i used to keep the cold air in the case.

jaypers · Post by **jaypers** » Fri Mar 28, 2003 3:48 am

Well finally following snowmoon's request I am able to post pictures of my duct! Incidentally I ended up buying a Canon Ixus 400 camera which is pretty awesome albeit rather costly! Mike - could you send me an expenses form so I can reclaim the cost from SPCR?

OK, so this is my first attempt at doing this so I hope it works! Before you look at them bear in mind I didn't build this thing for esthetics so yes, it is ugly as I have previously warned! It is made of corrugated plastic sheets.

This is it fitted:

Here's a few views taken out:

Here's the heatsink end - Yes, that is masking tape! It makes the opening shorter than the length of the Zalman and helps the airflow get sucked through the fins (helped the temp by 1c). I haven't experimented doing more 'masking' yet but some on the other side may help. What these photos don't show (I simply can't get the angle) is that bottom of the duct just touches the memory so it does wrap around/over all of the Zalman flower cooler fins.

You can see my old Ultrasilent Noiseblocker S2 here. I fix the whole thing to the case using screws going through the ends of the duct - the duct seems to do a reasonably good job of insulating vibrations. I now use a Panaflo L and the results are even better and quieter. I will post the results shortly...

Hope this of help/interest and any questions and recommendations gladly received/answered!

DaShiv · Post by **DaShiv** » Fri Mar 28, 2003 4:36 am

I, too, have had great success with ducting. My case suffered from horrid airflow, with a single intake and the PSU fan in my poor overworked Nexus acting as the sole exhaust. CPU temperatures were at 51C idle 58C load, with case temperatures soaring as high as 36-38C. Not good.

So I had an exhaust hole dremeled to the back of my case and attached a rather pricey Badong (http://store.yahoo.com/directron/badongs80.html) to connect it to my HSF (whose fan is blowing up, not down). Results: 43C idle 52C load 54C gaming. I'm guessing that the higher gaming temperature is due to the excess heat generated by my Radeon 9700 Pro. Case temperature is at 28C.

Keep in mind I added both a duct and an exhaust (with fan) for the duct, so the improvement is not just from the ducting, but also from how terrible the airflow was inside my case before. I chose the Badong because I was hoping for less noice from air turbulence with a more consistently-shaped tube, but it's definitely pricey for something as simple as a duct. For those with poor airflow, ducting can definitely be beneficial.

By the way, the fans powering the duct at either end are a Panaflo L1As at about 6-7 volts or so. I've read that fans in series are a bit useless, so I might experiment with removing one of them later on.

Mark Larson · Post by **Mark Larson** » Sat Mar 29, 2003 10:49 pm

Well, since this topic is back up, allow me to post another pic - this is with my Tbred B 1700+.
There is a Panaflo L1A mounted on the case, exhausting from an AX-7 without a fan on it.

EDIT: I just looked at the Badong and that's what it seems to be, except my dryer hose cost all of $ 1.92

SpyderCat · Post by **SpyderCat** » Sun Mar 30, 2003 3:32 am

Mark Larson wrote:Well, since this topic is back up, allow me to post another pic - this is with my Tbred B 1700+.
There is a Panaflo L1A mounted on the case, exhausting from an AX-7 without a fan on it.

That's the way to go Mark !

At what volts are you running your Panaflo L1A ?
Did you fit a shroud around your AX-7 heatsink ?

Regards, Han.

Mark Larson · Post by **Mark Larson** » Mon Mar 31, 2003 7:51 am

SpyderCat wrote: That's the way to go Mark !

At what volts are you running your Panaflo L1A ?
Did you fit a shroud around your AX-7 heatsink ?

Regards, Han.

Thanks!

The L1A is at 12v, and the duct goes all the way to the bottom of the heatsink, so there's no need for a shroud.

Sleeper · Post by **Sleeper** » Mon Apr 07, 2003 6:43 am

Mark Larson wrote:
EDIT: I just looked at the Badong and that's what it seems to be, except my dryer hose cost all of $ 1.92

You should try to replace with aluminum dryer hose.
It would look better and disipate heat better.
Only problems would be:
1) would it resonate sound more?
2) is it flexible enough.?

Bob

Sleeper · Post by **Sleeper** » Mon Apr 07, 2003 6:47 am

jaypers wrote:.....I haven't experimented doing more 'masking' yet but some on the other side may help. ....

Try duct tape or packing tape instead.
Masking tape is not meant to be permanent, and may fall off.

Bob (sleeper)

My Ducting - excellent results

My Ducting - excellent results

plastic hose