Mounting a second fan on the back of the case (Antec SLK3000B)

With the summer approaching, I am making some experiments trying to cool my pc as much as possible while keeping it quiet. Now, airflow in the case is made by 2 fans: the intake fan, a Papst 4412 F/2GLL, pulls air inside the case from the front, the exhaust fan, a Antec Tricool coming with the SLK3000B, pushes air out to the back; in addition, the psu fan pulls air from the top of the motherboard through the psu to the back.
Since I bought a second Papst 4412 F/2GLL, I tried positioning this fan in different locations to see which one conributes the best to the cooling. One of these is the back of the case, in the bottom, where there would be additional cards: it pushes air out of the case through the back slots.

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Fans

Intake by one Papst 4412 F/2GLL (front, bottom)
Exhaust by the Antec Tricool (back, top) and the second Papst 4412 F/2GLL (back, bottom)

All fans are set at low speed, the Tricool by its speed switch and the two Papst by the fan controller (the front one by a speed knob, the back one by a 5V/12V toggle switch).
CFM balance: -30 CFM (negative pressure; expected: even more cooling, pulling dust inside through the side vents)

Papst 4412 F/2GLL

I had to retrieve its specifications from the net because it came without any package: from silentpcreview:

Voltage	Noise	RPM	CFM	Power
12V	24 dBA@1m	1290 RPM	54 CFM	0.64W
9V	20 dBA@1m	980 RPM	40 CFM	0.48W
7V	<19 dBA@1m	750 RPM	30 CFM	0.38W
5V	<19 dBA@1m	490 RPM	18 CFM	0.30W
@25 CFM (6.2V)	<19 dBA@1m	660 RPM	25 CFM	0.35W

Antec Tricool

I retrieved its specifications from silentpcreview too because it came with the case:

Voltage	Noise	RPM	CFM	Power
12V (High)	36 dBA@1m	1930 RPM	73 CFM	2.73W
9V	29 dBA@1m	1530 RPM	58 CFM	2.00W
Medium	27 dBA@1m	1430 RPM	53 CFM	1.90W
7V	23 dBA@1m	1220 RPM	45 CFM	1.54W
5V (Low)	20 dBA@1m	870 RPM	30 CFM	1.18W
@25 CFM (4.5V)	~19 dBA@1m	740 RPM	25 CFM	1.00W

Mounting

I removed all the backplates from the back of the case (the air will flow out through them), the fan will be fixed to the case using two of them. Since they are too short to screw a 120 mm fan on them, I had to make two extenders onto which the fan is screwed: the pics are self-explanatory.

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118.46 KB	108.25 KB	159.27 KB	107.33 KB	118.19 KB

Results

The temperature of the motherboard, the hottest component, still reaches 47° with cpu at 100%, with and without the third fan and back openings. There is still hot air around the motherboard and video card, it seems that the additional exhaust fan doesn't improve cooling performance when set at low speed; when revving faster it helps a bit but it's more than audible.

Posted by: z24 | Sun, Jun 17 2007 | Category: /hardware | Permanent link | home
Tagged as: case, cooling, fan, hardware, silencing

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