PA120.3 Push or Pull?

The Asgard said:
Depends on your case air flow and what you want to do with the air?
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Its basically getting fitted to the inside top of a Lian Li PC70

I'm thinking of having the 120mm fans at the bottom of the rad pushing air up and through the rad and out of the case through holes cut in the top of the case.

Was thinking of plugging in the 6 remaining 80mm holes with 7v 80mm fans all set to pull air into the case to aid the flow of air up and out of the top through the rad.

Thoughts?
 
Sounds good. I always like to pull air through the radiator but it depends on the room in the case. I would have thought you will be tight.

Like you say you can reverse the flow on the back fans to pull air in.

I would also use some draft excluder between the fans and the shroud to get a good seal and keep vibrations down. You need the heavy sticky black foam type stuff thats sticky on one side.

Also get a fan controller so you can tweak for performance or silence.
 
I have my Panaflo 38mm fans pulling air through my rad on my PC-75 and its giving me nice temps.
 
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From thermochill FAQ:

"For best temps on the PA series, testing currently shows PUSH to be the best solution... shrouded vs unshrouded exhibits minimal benefits, in the region of upto 2%. Fans pushing as opposed to fans pulling exhibits increases of upto 4%, and is roughly equivalent to running a shroud with fans in a pull configuration."
 
I'm sure Marci will be along to correct me in a moment, but I'm pretty sure Thermochill are currently suggesting push is better.

Thermochill FAQ said:
For best temps on the PA series, testing currently shows PUSH to be the best solution... shrouded vs unshrouded exhibits minimal benefits, in the region of upto 2%. Fans pushing as opposed to fans pulling exhibits increases of upto 4%, and is roughly equivalent to running a shroud with fans in a pull configuration.
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http://www.thermochill.com/faq.html

[Edit]DARN! - 2.5 minutes of cut'n'paste and I'm beaten to it![/Edit]
 
I use a shroud on my PA, it hasn't really improved temps at all, I put it on there mainly so I could drill through the side of it for mounting (used some of those pump anti vibration mounts), the rad also came which the neoprene gasket to fit between the fans and rad so you get a nice seal. BTW I push. :D:D
 
Sorry folks... initially push was better, but there's been recent testing showing otherwise and the FAQ still needs updating...

"Minimal difference" is a term used a lot for push vs pull... but realistically, in radiator performance terms that 1 degree is a HUGE amount of difference when you're talking temp changes in the regions of hundredths of a degree per watt of heat, which means that a setup with 1 degree colder temps could be able to remove up to an extra 50watts of heatload (if asked to) over the warmer setup.

Pull (suck) provides more even airflow which generally results in better performance over the same fan on the same radiator in push...

Will also compare shrouded, unshrouded, suck (pull), and blow (push) air-flows.

Was just messing with the equipment a bit last night, putting a Yate-Loon on a PA120.1 radiator with a shroud, in suck or blow arrangement. I was able to position the anemometer on the other side of the radiator to get an idea of the evenness of the air-flow through the radiator. Used the tachometer to measure the fan speeds, and the noise meter the fan noise levels. I haven't calibrated the fan noise levels yet to any base reference point, so I won't report the absolute values I got, just the relative values.

Free-air: +0dBA noise, 1480rpm speed
Shroud Suck: -2.7dBA noise (i.e. quieter), 1350rpm speed
Shroud Blow: -3.0dBA noise (i.e. quieter), 1460rpm speed

I found the noise level differences, and the fan speed differences to be quite intriguing. If the fan is spinning faster, it's pushing more air-flow in the blow-mode.

However, using the anemometer on the other side found that with the shroud, in blow mode, the air coming out the edges of the radiator had about an 80% higher velocity than the air coming out the dead-center. In suck mode, the overall air-velocity appeared lower (will need to measure properly later on full-testbed), but it was more even, with only about a 25% variation between the edges (higher) and the dead-center (lower).

So yeah - this throws a cloud over the general suck/blow debate. The fan appears to like to blow much better than to suck, but the air-flow is less even, even though it's of a higher velocity. The fan is also quieter in blow-mode.

It would appear (without further testing) that putting a fan into blow-mode on a radiator with a really deep shroud (60cm) to straighten out the air-flow would be the best way to go, but that's not terribly practical.

*snip*

It seems to be a scenario of while blow creates more air-flow, the unevenness of the flow through the core hurts performance. Performance does not scale linearly with air-flow, and so it's always better to have even air-flow over the entire core area, rather than some areas receiving twice the air-velocity of other areas.
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Source: http://www.xtremesystems.org/forums/showthread.php?t=150261&highlight=fan-pull
 
thanks for all your replies!

Well it sounds like my best bet would be to have the fans on top of the rad pushing cool air fed from holes on the top of the case over the rad and down through the case, then using the remainder of the fans in the case 6 x80mm (LianLi PC-70) to pull air out of the case at the bottom.

Thoughts?

DeadMan

p.s bit arrived today so its dremel time tonight :D
 
Marci said:
Sorry folks... initially push was better, but there's been recent testing showing otherwise and the FAQ still needs updating...

"Minimal difference" is a term used a lot for push vs pull... but realistically, in radiator performance terms that 1 degree is a HUGE amount of difference when you're talking temp changes in the regions of hundredths of a degree per watt of heat, which means that a setup with 1 degree colder temps could be able to remove up to an extra 50watts of heatload (if asked to) over the warmer setup.

Pull (suck) provides more even airflow which generally results in better performance over the same fan on the same radiator in push...

Source: http://www.xtremesystems.org/forums/showthread.php?t=150261&highlight=fan-pull
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Thanks Marci, perhaps it does not make that much difference after all..

:confused:

Could you recommend an ideal setup in my case without using a Performance Shroud?

Cheers

DeadMan
 
Well, I'm thoroughly confused, but as I'm running PA120.3's just to cool the CPU it makes very little difference anyway:D
 
Could you recommend an ideal setup in my case without using a Performance Shroud?
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Well, I'm thoroughly confused, but as I'm running PA120.3's just to cool the CPU it makes very little difference anyway
Click to expand...

Like it says...
Pull (suck) provides more even airflow which generally results in better performance over the same fan on the same radiator in push... *snip* ...while blow (push) creates more air-flow, the unevenness of the flow through the core hurts performance... *snip* ...and so it's always better to have even air-flow over the entire core area (ie: pull), rather than some areas receiving twice the air-velocity of other areas (ie: push)
Click to expand...
 
Well I have it setup pulling air through the rad and out of the top of the case with 4x 80mm fans as cool air intakes at the bottom.

It works quite well apart from my 8800GTX causing a heat build up in the case.

I have ordered the EK 8800GTX (acetal top version) to hopefully sort this out.

I have gone from about 25 - 30db to around 15 - 20db.. and its amazing.

The hard drive clicks are starting to drive me nuts now though.

DeadMan
 
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