120 vs 140 Fan Debacle

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Slayer88

Slayer88

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Hi guys,

I am yet to test by looking at temps, but was hoping some expert on fans might be able to help here.

So, I have the option to put a 120 or 140 mm fan at the front of my case and it needs to pull air through a metal mesh and a nylon fan filter/mesh.

140 mm - 72.8 CFM - 2.4 H₂O
120mm - 71.3 CFM - 2.9 H₂O

The 140 pushes more air but has less SP while the 120 is the opposite.

Considering this is my only intake, which one should i go for. I feel the 120mm is pushing more air. But I wanted to hear the experts thoughts?

TIA.
 
Air flow and static pressure have a negative correlation. When air flow increases, static pressure decreases; and when static pressure increases, air flow decreases. Though maximum values for air flow and static pressure are specified, the fan will not output both maximum values at the same time. Hope you get the idea ...
 
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Ankit2306 said:
Air flow and static pressure have a negative correlation. When air flow increases, static pressure decreases; and when static pressure increases, air flow decreases. Though maximum values for air flow and static pressure are specified, the fan will not output both maximum values at the same time. Hope you get the idea ...
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Thanks for your reply. So, all things considered, which of the above 2 should I use?:)
 
The 120 should be the best choice , considering all other factors, a picture of your system could be the final vital clue , as I am unaware of the chasis and other coolings in consideration..
 
Ankit2306 said:
The 120 should be the best choice , considering all other factors, a picture of your system could be the final vital clue , as I am unaware of the chasis and other coolings in consideration..
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IMG_20220209_182752.jpg

Here it is. Thanks
 
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The 120 should be the best option here , make sure there is least amount of obstruction, also I am sure there are many other experts in this community, who might shed some more thoughts, which I might have overlooked.
 
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So what is unknown about the fans is the airflow through your air filter. And since the fan manufacturer doesn't have your air filter, it is difficult for them to test with it.

In spite of 36% size advantage over the 120mm fan, your 140 mm fan barely moves 2% more air, without any filter obstruction. And the 120 mm fan has a 21% higher static pressure. My best guess too will be to use the 120mm.

But even more so, is there no 140mm fan in the market which has either a higher airflow, or higher static pressure, or both ? This one seems inadequate. And why limit yourself to just a single intake, in spite of having 3 exhaust fans ? The case seems to support at least 2 intakes, even assuming you have blocked the bottom intake due to your artistic PSU work. Since the pressure might be low at the top, and top-left corner of the case, it will suck in unfiltered air through unintentional vents.
 
kiran6680 said:
But even more so, is there no 140mm fan in the market which has either a higher airflow, or higher static pressure, or both ?
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I have many fans and not in a position to spend more on another fan. The above 2 fans are what are already in my possession.
kiran6680 said:
The case seems to support at least 2 intakes, even assuming you have blocked the bottom intake due to your artistic PSU work.
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The above is sadly true, in the chase for aesthetics, i have scarified some airflow. Though the top front had full mesh, it did not officially support a second fan, but i could add one if my top fron led lit logo was not there.
dexterz said:
OT, very jealous of the clean look. What case is this? Very neat cable management. Is it because of the case or did you do anything extra for it?
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Thanks. The case is the Lancool K62. 10+ years old, I have done numerous mods to it. See below.

Orginal
11-112-239-19.jpg

11-112-239-20.jpg


Modded
IMG_20220209_182427.jpg


PXL_20220209_175332199.NIGHT.jpg
 
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Slayer88 said:
I have many fans and not in a position to spend more on another fan. The above 2 fans are what are already in my possession.

The above is sadly true, in the chase for aesthetics, i have scarified some airflow. Though the top front had full mesh, it did not officially support a second fan, but i could add one if my top fron led lit logo was not there.

Thanks. The case is the Lancool K62. 10+ years old, I have done numerous mods to it. See below.

Orginal
View attachment 126837
View attachment 126843

Modded
View attachment 126839

View attachment 126842
Click to expand...
Slayer slaying
 
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Slayer88 said:
Thanks. The case is the Lancool K62. 10+ years old, I have done numerous mods to it. See below.
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any current stock case that looks similar to what you have done?

also about the air flow thing, it's been a while since i read it, but wasn't it something along the lines of inflow should equal outflow to maintain equilibrium or some zen?
 
dexterz said:
also about the air flow thing, it's been a while since i read it, but wasn't it something along the lines of inflow should equal outflow to maintain equilibrium or some zen?
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It is somewhat true, it helps in minimising dust deposits, but I'm aware of only one long term test* for this. It found that local pressure zones matter much more than overall number of fans in the case. Since a case is very far from air tight, pressure within the case varies drastically from one place to another. So even when number of intake fans is the same as the number of exhaust fans, locally there are low pressure and high pressure zones in the case, and they might pull in the dust if that area has no filter.



* That test started before the YouTube channel "Linus tech tips" started in its current form, and was completed just a few months/ years ago (don't recall now). They analysed the dust deposits in a PC running for years.
 
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Slayer88 said:
A PSU shroud is kinda common these days, but LED lit stuff is totally custom and will not be available on anything stock to the best of my knowledge.
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cool. thanks slayer. im not all that into RGB. more into functionality than aesthetics. cable management and airflow before rgb/led
 
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