120>80mm

PlawsWorth · 09-11-2002, 10:35 AM

I was thinking of using a tunnel from my 120mm papst fan on the bix to transfer the "hot" air through a tunnel to a 80mm fan (got a miditower, chieftec) since I can't put a 120mm fan at the back. this way the hot air will go directly out into the room and never heat up the case temp. I'm just wondering of how loud it can get when I have 80mm fan and a 120mm? //Plaws

gmat · 09-11-2002, 03:20 PM

Could you, for example, tilt the funnel and have its output on the side panel ? (and make the appropriate opening on said side panel...) Just a 90° turn...
80mm fans are *loud* especially if you want them to flow like a 120mm does...

airspirit · 09-11-2002, 05:41 PM

It'll cause hellacious turbulence, and in the end it might make your system less efficient if I am reading you right. Think of water in a funnel. You can fill the top faster than the bottom can drain. The 120mm will be laboring to fight the back-pressure from the funnel, and the 80mm will be getting pushed by the air behind it. Both translate into louder fans. Also, this will slow airflow rates and will cause higher temps. You'd be better off with 2x120, or, alternatively, you could run the 80mm on 12V and tune the 120mm down to 7-8V with a potentiometer. That should prevent the air pressure inside the funnel from staying greater than ambient.

Did any of that make sense? My brain is cooked today.

MadDogMe · 09-12-2002, 02:46 AM

The air will prolly still be cooler than the 'incase' air, so it won't be 'hotair'

let it circulate the case!, have a nice big slow/quiete blowhole up top...

09-11-2002, 10:35 AM	#1
PlawsWorth Cooling Savant Join Date: Aug 2002 Location: Sweden Posts: 248	120>80mm I was thinking of using a tunnel from my 120mm papst fan on the bix to transfer the "hot" air through a tunnel to a 80mm fan (got a miditower, chieftec) since I can't put a 120mm fan at the back. this way the hot air will go directly out into the room and never heat up the case temp. I'm just wondering of how loud it can get when I have 80mm fan and a 120mm? //Plaws __________________ cocaine addict

09-11-2002, 05:41 PM	#3
airspirit Been /.'d... have you? Join Date: Jul 2002 Location: Moscow, ID Posts: 1,986	It'll cause hellacious turbulence, and in the end it might make your system less efficient if I am reading you right. Think of water in a funnel. You can fill the top faster than the bottom can drain. The 120mm will be laboring to fight the back-pressure from the funnel, and the 80mm will be getting pushed by the air behind it. Both translate into louder fans. Also, this will slow airflow rates and will cause higher temps. You'd be better off with 2x120, or, alternatively, you could run the 80mm on 12V and tune the 120mm down to 7-8V with a potentiometer. That should prevent the air pressure inside the funnel from staying greater than ambient. Did any of that make sense? My brain is cooked today. __________________ #!/bin/sh {who;} {last;} {pause;} {grep;} {touch;} {unzip;} mount /dev/girl -t {wet;} {fsck;} {fsck;} {fsck;} {fsck;} echo yes yes yes {yes;} umount {/dev/girl;zip;} rm -rf {wet.spot;} {sleep;} finger: permission denied

09-11-2002, 03:20 PM	#2
gmat Thermophile Join Date: Mar 2001 Location: France Posts: 1,221	Could you, for example, tilt the funnel and have its output on the side panel ? (and make the appropriate opening on said side panel...) Just a 90° turn... 80mm fans are loud especially if you want them to flow like a 120mm does...

09-12-2002, 02:46 AM	#4
MadDogMe Thermophile Join Date: Aug 2002 Location: Just shut up ;) ... Posts: 1,068	The air will prolly still be cooler than the 'incase' air, so it won't be 'hotair' let it circulate the case!, have a nice big slow/quiete blowhole up top...

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)