Fan on Fan action - Overclock.net

rabies229 · 10-16-06

lol.. funny title..but its what this is.

okay so i have a 80mm fan on the side of my case that almost lines up with the 120mm on the big typhoon.. dont mind the dust or wires.. those are old pics and after i took them i cleaned out the case again so dont think its still there..

My question regards the flow of air that the big typhoon is recieving ..

as you can see from the pictures it is a very tight fit between the BT and the 80mm fan on the side :S
my main question is that if it would be better to restrict the bt to only intake air by using something like duct tape because i dont think it would o me any good to get a 80mm to 120mm pipe thing (lol) because it is already a tight fit.

should i infact just restric the 120mm to sucking air from the 80mm .. im really not sure of what to do because i am not the best at air control.

cgrado · 10-16-06

just take teh 80mm off and put a filter on.

rabies229 · 10-16-06

would that optimize the airflow to the BT?

cgrado · 10-16-06

Quote:

Originally Posted by rabies229

would that optimize the airflow to the BT?

it would let the BT take in air from where ever it wanted, and would most likely take in air form around it because taking it from a filter would be too much work. you could always get a bigger case.
or you can use something like this and put a 120 on the outside to match the airflow of the BT's fan.

Syrillian · 10-16-06

Yeah, that setup is somewhat confusing as the intake is blowing the drawn warm air back down onto the processor and HSF. The imbalance of the pressures (120mm vx. 80mm) may have casued a "mushrooming" effect to the airfronts when they met. Just more thermal confusion inside the case.

I had the same dilemma. Utlimately I wanted a slightly positive air-pressure in the case, so balancing was the key. At one time I had a setup (80 on the side) similar to yours I changed the 80mm side intake to an exhaust, and supplemented the addition draw with 5-1/4" bay intake. this evolved into removing the 80 in the bay and modding the case so that a high CFM 120mm would fit.

As a rule of thumb, the side fan should be an exhaust, but under some circumstances, that practice is questionable.

Honestly, I did not notice much of a drop, -1C.

dragosmp · 10-16-06

Typhoon's 120 fan has a certain CFM. Let's suppose it's 54.4CFM (I found this on the web). The 80mm fan should supply this from the outside, but this is almost impossible as you would need 6-8000rpm and produce an inferal noise. As you can see linking the Typhoon's 120mm and the outer 80mm fan would be a bottleneck for the typhoon's fan.
As an alternative, if you don't link those fans together it's reasonable to say that the BT pulls around 20-25CFM from the lateral 80mm fan and the rest up to 54.4CFM from the air current that traverses the box from the front fan towards the rear fan. This way the BT's 120mm fan would be alimented with fresh air from the lateral 80mm fan, but also with somewhat warmer air from the front fan. Anyhow, this is a better option than having the BT alimented only with 25CFM fresh air and the rest up to 54.4 no air.

My 2 cents.

Highly-Annoyed · 10-16-06

If you wanted to duct the fans so that the air is channelled from the outside of the case, though the 80mm fan, directly to the 120mm fan of the BT, you would have to ensure that the 80mm fan moved as much air as the 120mm fan does. Their respective CFM would have to be equal for the solution to be better than the existing configuration.

You can get 80mm fans that move as much air as many 120mm fans, but as mentioned in this thread so far, there would be a price to pay in terms of noise. Depending on the CFM of the 120mm however, you may be able to find an 80mm that matches its CFM whilst producing a bearable level of sound.

Good Luck!

Highly-Annoyed

Pythagoras · 10-16-06

My opinion on the subject would be to remove the 80, enlarge the opening, add a filter, put a larger cfm fan on the BT, and duct it directly to the outside. Your BT will then be getting the coolest, cleanest air available and the extra cfm's will help make the inside of your case into a positive pressure atmosphere; this will keep dust from being sucked into the little cracks that every case has somewhere. I did mine a little differently, but it is a similar idea. I used two 120's on the bottom as filtered intakes and this seems to keep my interior cool and clean.

**ira-k** · 10-16-06

Here are a couple high cfm 80mm fans the fist one isn't to bad but the second one would almost be unbearable....http://www.sidewindercomputers.com/pa80ulhisp.html
Panaflo 80x25 Ultra High Speed...........................http://www.sidewindercomputers.com/de80tfexhisp.html
Delta 80x38mm TFB0812UHE Ultra High Speed

gonX · 10-16-06

Quote:

Originally Posted by Syrillian

[...]ay have casued a "mushrooming" effe[...]

Man, I just started thinking of this one: Clicky

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Fan on Fan action

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