I have started to MOD one of my two Rack Mount Cases (very cheaply). I was able to place a 120mm fan in front, which was a major pain in the rear since it is a Steel Case and I had to cut out two layers of Steel.

I want to find some Aluminum Rectangle Ducting, apx 4" (high) x 7" (wide) x 6" (deep), to direct air towards the MOBO and the back of the case. Here are my questions:

1) Will this increase the sound of the fan?
2) Will the Ducting increase or decrease the effectiveness of the fan?
3) Will the Aluminum increase the inside temps?

Thanks

So you're going to put the ducting inside the case, behind the fan right?

You might create some stagnant spaces around the outside of the ducting, not a problem if there's nothing there to make too much heat. This might affect the inside temps in some localised spots, like up front in the case, next to where the duct is. Bearing in mind that these spots had NO air before the fan was added, so they're not going to get any worse.

I don't think it'll affect the noise too much, it could even make it quieter if you can place some kind of sound deadening on the inside of the duct, and place the fan at the inside end, instead of up against the case. Some of the duct insulation the HVAC guys use might do nicely if you can get it thin enough, if not cut some thinner...

Try a few different combinations, experiment with cardboard to check it out. Suck it and see, is what I always say...

And then let us know what worked best so we can do it LOL

1. Sometimes a resonance can set in, but most likely will decrease noise if you take steps to avoid resonanace.
(adding insulation, foam seals instead of direct contact)
2. Ducting directs air where you need it most, any loss of airflow is made up by getting it to the hot spots .
3. Not enough to worry about, unless the design restricts case flow ALOT

Look under the hood of a new car, they have spent alot of money on R&D for a balance between noise and airflow, they use resonance chambers to decrease noise. You could copy that if noise increases (There will be a TINY decrease in airflow though)
I made a cardboard duct with a exhaust fan at the end and my temps dropped 2-3 degrees at the cpu.

Check this out..may give you some ideas..
http://www.sunbeamtech.com/new/produ...oler%20kit.htm

Thanks for the information.

[quote]So you're going to put the ducting inside the case, behind the fan right?[quote]

Yes, the fan will be in the front of the case with the ducting inside.

[quote]You might create some stagnant spaces around the outside of the ducting, not a problem if there's nothing there to make too much heat. This might affect the inside temps in some localised spots, like up front in the case, next to where the duct is. Bearing in mind that these spots had NO air before the fan was added, so they're not going to get any worse.[quote]

Actually there were two 80mm fans that were side by side. There was not enough air getting inside to cool down the system enough. By opening up the front and replacing the 2 80mm fans, I was able to reduce my temps by almost 10c.

There will be a Hard Drive above the Duct, with it's own cooling fan. The rest of the area should not be affected.

[quote]And then let us know what worked best so we can do it LOL [quote]

I will update and even include pics when it's done.

[quote]1. Sometimes a resonance can set in, but most likely will decrease noise if you take steps to avoid resonanace.
(adding insulation, foam seals instead of direct contact)
2. Ducting directs air where you need it most, any loss of airflow is made up by getting it to the hot spots .
3. Not enough to worry about, unless the design restricts case flow ALOT[quote]

1. I'm hoping by painting the inside of the duct it will help make it quite.
2. I really need the air to reach the back of the case where it is needed the most.
3. The design of a rack server case does restrict adding intact fans which is part of the issue. This comes more into play when you have two side by side.

[quote]Check this out..may give you some ideas..
http://www.sunbeamtech.com/new/prod...ooler%20kit.htm [quote]

Good idea an link, however I need more of a Rectangle ducting rather than round. I also want it to be a straight shot to direct the air where I need it.