[SOLVED] Mixing Fans for Push/Pull

Cheshy-Nyan

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May 7, 2019
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Hey guys. I will be building my first custom loop in July, and I am looking at push/pull configurations for the two radiators I will be using. Too be honest, two radiators is probably a bit of overkill, especially as they are 360mm ones ( either the Corsair XR5 or the XR7, or possibly one of each. looking into what will fit in my case ). For the fans, I was going to use Corsair QL120 on one, with 41.6 CFM as the pull side, and either the BykSki CF-APRBW-V3 with 64.8 CFM or the ID-Cooling NO-12015-XT with 54.6 CFM as the push. For the second radiator, it would be Corsair LL120 with 43.25 CFM as pull and either the Bykski or ID-Cooling fans as push. One radiator would be intake, the other would be exhaust. The case I will be using is the Lian Li O11D Evo, which is why I am worried about the sizes of the rads. The XR7 should fit at the top ( it would be the exhaust ) while the XR5 would, I think, be better for the intake. it would be side mounted.

Thanks in advance for any help!
Chesh
 

Imacflier

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Jan 19, 2014
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So much I disagree with: First the fans on a top mounted radiator should blow into the case. Consider: a radiator can cool no more than the ambient air around it. (If the coolant were cooler than the ambient air, the air would WARM the coolant!) Since the hot air inside the case will rise, that will make the ambient air, if the top mounted rad is the exhaust, the hottest air in the case and increase the coolant temperature.

Push/pull fans...just don't do anything...I recently ran my own tests. Consider, you should be measuring the fan RPM not the rated air flows. If two identical fans are attached directly together in push/pull unless one or both of them rotate faster, then air flow will be unchanged! So stick with the single fan with the highest rated airflow!

GL

Larry
 

Cheshy-Nyan

Commendable
May 7, 2019
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Forgot to post my question, guess being up so late can do that to you. My question is, would I get away with using the ID-Cooling fans, which would be my preference as they are slimline and also feature an adjustable fan speed?
 

Viking2121

Distinguished
Im no water cooling expert, but its best to keep a push pull configuration with the same fans, if you have a higher CFM fan blowing into the rad and threw a lower CFM fan, the lower CFM fan is just going to probably spin faster than what its rated and well its not going to do much as the faster CFM fan is doing all the work, probably would be better4 off with just the high CFM fan.

Probably be a better config if 1 rad is only Corsair QL120 fans, and the other rad only the BykSki for example.
 

Imacflier

Distinguished
Jan 19, 2014
369
2
18,865
26
So much I disagree with: First the fans on a top mounted radiator should blow into the case. Consider: a radiator can cool no more than the ambient air around it. (If the coolant were cooler than the ambient air, the air would WARM the coolant!) Since the hot air inside the case will rise, that will make the ambient air, if the top mounted rad is the exhaust, the hottest air in the case and increase the coolant temperature.

Push/pull fans...just don't do anything...I recently ran my own tests. Consider, you should be measuring the fan RPM not the rated air flows. If two identical fans are attached directly together in push/pull unless one or both of them rotate faster, then air flow will be unchanged! So stick with the single fan with the highest rated airflow!

GL

Larry
 

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