duct and exhaust but running warm still???

[demon-eater]

I just got done building a duct for a my heatsink and a exhaust hole in my case but im running alittle warm right now...

my duct is aluminum covers my fan on the sides and isn't air tight yet... runs from there to the back of my case where i cut a hole that is small i think im gonna make it bigger and bend the aluminum so that it is bigger as well.. now my exhaust is a 120mm i think its really really big almost as wide as my full size atx case so its a monster its located right above my heatsink and to the left alittle...

I also have a 80mm on intake and have another 80mm that i wanna put in but don' know where to put it... any ideas??

now my temps were 26C idle with the case on and without the duct and exhaust.. and like 44C load running folding (microsoft pinball took it to 50C after 10minutes of playing that game runs 100% all the time) now its 28C idle and well i deleted folding so i can't check that and can't remember where to get it at..

[nihili]

OK, from your description it sounds like you're using the heatsink fan to draw air through the duct. Ducting can be a great help, but it makes your fans work harder so unless you've got a monster hsf, you're probably underpowered on the duct. Not to worry though, that's where your other 80mm fan goes.

Mount the 80mm fan to your case where the duct goes, then attach the duct around it. With both fans blowing in the same direction you'll see a nice increase in airflow. It's important that the duct be reasonably airtight.

You'll want to experiment with using the duct as an intake and as an exhaust. I'm having the best luck using it as an exhaust. At least I did in the summer, I haven't double checked since the weather started cooling off.

It would be helpful to tell us:
What heat sink and fans you're using.
What processor you're using.
What the size of your duct is (cross section or diameter, and maybe a description.)
The position of the other fans in the case.
What kind of case you have.

That should get us started.

nihili

[demon-eater]

im using a SK-6 with the 8035rpm fan (Y-TECH?), 80mm , 120mm, and power supply 80mm,

im using a 1.0 athlon oc to 1.120
3" dryer aluminium duct

80mm in bottom front sucking air in, 120 right infront of my power supply on top of the case (no room inside it)

full atx

[Intraveinous]

44C while Folding isn't terrible... I'd try adding the other fan at the end of the duct as nihili said... Let us know of the results.
Peace
John

[nihili]

Ok, without actually looking at your system, here's my best guess as to what's going on. You've said your duct isn't airtight, did you bend the duct to fit around the fan and just not seal it? Or do you just have the duct sort of pointing at the fan? From your description, I'm guessing the latter. Also, how do you have the duct attached to the case?

If I'm right, then it sounds like what you've done is to increase the static pressure that the fan has to work agains by blocking some of the clear air flow with the duct. This happens any time you put a duct in. But if the duct isn't fairly tight, then the fan will still pull hot case air in around the edges. So you end up reducing airflow without substantially reducing the temperature of the air. If you fit the duct tightly around the fan, then while you still reduce airflow, you also substantially reduce the temperature of the air on the heat sink.

If you really want the duct to be efficient, here's how to do it. Get a small section of 4" dryer ducting and a 3-4 inch adapter from the harware store. Use the adapter to convert from the 3 inch duct coming off of the hsf to the 4 inch duct that will go to the back of your case. Then put your spare 80mm fan on that end of the duct attached to the side of the case. Using 2 inline fans decreases the static pressure that each of them has to work against. So you'll actually see a greater airflow of colder air across your heatsink. That's got to help.

Here's a picture of such a setup using vinyl ducting. The black piece is the adapter. You should also try the duct both as an intake an as an exhaust to see which works better on your system.

nihili

[demon-eater]

when pulling off my duct i destroyed it because it was only aluminum.. now later today when my dad gets home ill find out if we have any vinly dryer duct.. and yes my duct was fairly airtight around the fan... my problem now is making the hole bigger for the 80mm fan on the backside of my case.. i had made the hole with snips but i could only go so far because i have steel reinforcment stuff kinda like in the way.. ill have to take everything out of my case and get my dad to help me use his sawzall or his other thingy to cut through that.. ugh.. and yes my case looks exactly like the one in the picture except i have steel rod type things running in the top of my case and right below my power supply.. they do more harm than good i think