360mm rad - 240mm of fans

[Momo]

Anyone experimented/seen an article on using a 360mm radiator and only running 2 fans?

I've got a corsair obsidian 550d, would love to use an EK predator 360 setup with it.

Thinking i might just use two fans instead of three on the radiator, was wondering if there's any data out there on using less than maximum fan counts on coolers?

Cheers,

 

[Henri108]

Even running a rad without fans dissipates a lot of heat. So it's fine having a 360 with only 2 fans. It'll be better than a 240 rad with 2 fans.

 

[Momo]

yeah, i figured as much Henri. Was just wondering if there's any actual data on it

edit: actually, logistically speaking i could do three fans:

radiator mounted below two fans pulling air out of case
single fan mounted beneath radiator on far right spot, pullng air through radiator

... assuming there's enough room, not sure if it would be benefcial at all. I'm assuming it would be though.

FF
RRR
.....F

 

[Nobu]

I had been running my 280mm rad with two 120mm fans for a while with no issues. Swapping those for 140mm fans improved temps five, ten or so degrees, but they're also higher static-pressure/cfm fans.

I think the biggest thing would be the pressure drop caused by there not being a fan next to the other two fans, now a rather large gap between the fins and the fans. Depending on how focused the air being pushed by the fans is and the fpi of the radiator, it may not be a big deal, but it's something to consider.

 

[Momo]

wow Nobu, i'm surprised there was that big of a difference for you. I can only assume that the 140mm fans were higher static pressure / moved more aire than the 120mm they replaced...

 

[Nobu]

Yeah, there was a pretty big difference in airflow at the same RPM. With the smaller fans I could feel the air coming through the radiator, but not through the exhaust vents. With the bigger fans, you can feel air coming out all the vents, though it's not nearly a torrent at 900rpm--more like a trickle. Those are the only two fans in the whole case (HAF XB Evo).

 

[Dayaks]

If it's the same rpm bigger fans have an exponential effect. Generally wider blades, longer blades, and the tip speed is much higher.

 

[SomeGuy133]

Anyone experimented/seen an article on using a 360mm radiator and only running 2 fans?

I've got a corsair obsidian 550d, would love to use an EK predator 360 setup with it.

Thinking i might just use two fans instead of three on the radiator, was wondering if there's any data out there on using less than maximum fan counts on coolers?

Cheers,

I just got done testing different high performance fans with my H100i GTX and I found that even my 240mm rad was nearly 100% cooling water before it was returned to the CPU and I was doing 200-220 W TDP. So do what I did. Get an IR temp gun and measure the input and output temps. You will see 0 gain from more fans or more rads if the output temp is at room temp. This is where peltier cooler can come in handy by cooling water that has already been cooled to air temp. So depending on your flow rate and water quantity you could try to lower input temp so you could lower overall temp. I am curious how much help a simple 40-80 watt peltier would do. Would it be enough to lower CPU temps by 10-20 C? Too much work for me but it would require a lot of math to make an effective system. I would assume less water in the system the more efficient you could make it because it all has to do with temp differences.

Update: Testing Enermax TwiserStorm fans at 2500 RPM looking at rad temps
Rad temps at idle:
40-45 W TDP
CPU at 14-18C
Basement at ~20C according to IR gun
Rad at 22.5C input and ~21C output

Rad at full load:
~208 W TDP
CPU at 67-80C
Basement at ~20C according to IR gun
Rad at ~31C at input and ~22C at exit so this rad and fan is 100% cooling the water before return. I can actually use the IR gun and map the loop in rad

BTW the big thing is pressure. you want fans that have high pressure. different blades produce more pressure but less CFM so CFM is not the best measurement for heatsinks and rads.