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Specific ducting question

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RobxMcCarthy

Member
Joined
Jul 18, 2004
I would like to duct a 120mm fan ontop of my case directly onto the processor. I have some questions though.

What material should I use for the ducting. I'd like to fine (ultimately) a 120mm flexible material for ducting, as my zalman CPU heatsink is about 120mm wide, as well as the top intake. This would obviously be ideal.

Well I guess that's the only question really. lol. Well, thanks for any info that can be provided.
 

ClarkKent

Member
Joined
Jul 5, 2004
Location
Toronto, Canada
I've also been looking into making a CPU duct to the outside of my case. The best/only thing I've found so far is drier duct hose. You would be able to find it in the correct size and length. The only thing is how it looks. I checked out some auto stores they had some stuff that looked cool but nothing that had enough mobility for myself.
 

orionzbelt1

Member
Joined
May 28, 2004
Location
ESSEX UK
i have used flexible tube 120mm they use in to run cables threw underground i found this in my local builders merchants and got it cut to 1/2 meter in size my only worry about this stuff is that it had metal wire round it so i pulled the wire out of it just to make sure if anything happened it wouldnt short out. I ducted staright from my side case fan but unfortunatly it is not directly oposite my cpu so this is why i got the flexi stuff. i then cut it to size and ducted it from my 80mm side fan using silicon sealent to seal it round the case fan and now my temps have dropped by 5' idle and 10'c load
 

ClarkKent

Member
Joined
Jul 5, 2004
Location
Toronto, Canada
That is amazing. Any idea what the tube is actually called? Flexable tube can't be it's name. I'd like to see it if you have a cam or know where I could check it out.
 
OP
R

RobxMcCarthy

Member
Joined
Jul 18, 2004
Yeah I've mainly been looking at dryer venting... It's really flexible and... shiny, actually looks kind of cool.

now the Second dilema.. how to squish my power lines enough to get a big ole 4 inch wide duct through.
 

orionzbelt1

Member
Joined
May 28, 2004
Location
ESSEX UK
I wonder if they ship to the uk cause its had me thinking with a 80mm to 120mm adapter to the side or front and another adapter on the other end to a 92mm fan that can go on most cpu H/s apart from mine
 

nkcd

Member
Joined
Oct 24, 2003
oh yea, I did made a duct but didn't see much drop though ~1-3*C max. But I didn't seal it or anything, just a square box from my 92mm delta to the slk947U.

So the question is, does the duct have to be completely sealled?
 
OP
R

RobxMcCarthy

Member
Joined
Jul 18, 2004
well I never really saw the point of ducting fans that are straight across from the processor... They pretty much blow in a straight path anyway. I think that obviously the IDEAL setup would be to have a duct with a fan on both ends Probably hand made out of aluminum solid ducting to prevent pinching and to create the smoothest inner surface to minimize air turbulence. But a dryer vent is what i'm going to use.. cheap / easy.
 

orionzbelt1

Member
Joined
May 28, 2004
Location
ESSEX UK
nkcd said:
oh yea, I did made a duct but didn't see much drop though ~1-3*C max. But I didn't seal it or anything, just a square box from my 92mm delta to the slk947U.

So the question is, does the duct have to be completely sealled?

i


I only sealed it to keep it on plus i dont mind it looking a bit ugly as ordering new case on monday. I am using 80mm Thermaltake smart fan and my duct stops abot 10mm from the zalman and my temps are so much better.
 

nkcd

Member
Joined
Oct 24, 2003
I just removed my duct and nothing changed in the temp beside the fact that it fluctuate more between 28-32 giving me the same average temp (30*C) like I had when the duct was on. ::dunno::
 

ClarkKent

Member
Joined
Jul 5, 2004
Location
Toronto, Canada
Fans don't blow air directly straight out. The air comes off the fan blades on an angle there for going into your case. So having a case fan right across from your CPU is good but would be much better in a sealed duct.
 

Dcasole

Member
Joined
Feb 1, 2004
Location
Dacula, GA
Fans don't blow air directly straight out. The air comes off the fan blades on an angle there for going into your case. So having a case fan right across from your CPU is good but would be much better in a sealed duct.

I agree with Clark, I got a 4C drop when I installed a duct on the fan which is in my side cover . My sidecover fan was directly in line with the cpu so I used an 3 1/2 inch rubber pipe coupler that I purchased at a hardware store. It is not sealed to the cpu fan as it ends just short of it

Dcasole-DSC01133.JPG


It ain't pretty .................. but it works :beer:
Dave
 

nkcd

Member
Joined
Oct 24, 2003
i made one out of cardboards. after I removed today, I saw a lot lot of dust clogged on the fins of the SLK947. :(
 

orion456

Member
Joined
May 31, 2004
A duct should be sealed if its an intake this avoids significant churning around the edges of the fan. On the other hand, an exhaust duct should be about one centimeter off the fan surface to allow case air to enter the low pressure zones at the square fan's corners. Otherwise air being blown down the duct must circulate back around to fill the vacuum.

You won't see much effect from a duct if your system already has good circulation because cool external air is already entering the case efficiently. However, with an exhaust duct you can turn off the other exhaust fans to lower noise.....or if you have poor circulation you will see a nice drop in temps.
 

nkcd

Member
Joined
Oct 24, 2003
orion456 said:
A duct should be sealed if its an intake this avoids significant churning around the edges of the fan. On the other hand, an exhaust duct should be about one centimeter off the fan surface to allow case air to enter the low pressure zones at the square fan's corners. Otherwise air being blown down the duct must circulate back around to fill the vacuum.

You won't see much effect from a duct if your system already has good circulation because cool external air is already entering the case efficiently. However, with an exhaust duct you can turn off the other exhaust fans to lower noise.....or if you have poor circulation you will see a nice drop in temps.


ah, now I know why I don't see much drop in the temp is because my case has good air circulation (27*C Idle and 32*C load). Also, another fact is that my duct is not completely sealed. Does anyone have any idea on what can I use to make a tight seal duct from my 92mm to my SLK947 (since both ends have completely different dimensions). It won't be a complete straight path since the HS will be a lil bit to the upper right hand (when you look into the side panel) of the Fan. ~0.5" to the right and ~0.3" higher.
 

enduro

Member
Joined
Mar 31, 2004
Location
Montgomery Alabama Yall
I've found that with ducts, especially long tubed ducts, that the higher the pressure put out by the fan, the greater the temp drop. I have this duct attached to my 92mm Tornado and usually have it running at half speed. I had a temp drop of around 7°C with this setup. It's pretty ugly, but I got is for 1.50 at Home Depot.
ENDURO'S DUCT