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Best way to route airflow for custom loop?

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SPL Tech

Member
Joined
Nov 28, 2006
I'm going to be trying my first custom loop. All hardline tubing. Single 280 mm Corsair radiator mounted in the front with two QL140 fans. These are low speed fancy RGB 140mm fans that only run at 1250 RPM. It's going in a NZXT Elite H510 case. I'll be cooling a 2080Ti and 9700k, both being overclocked so I suspect it's going to pump out a ton of heat. The question is whether I should pull air from in the case and have it exhaust out the front or take clean air in from outside and pump the heat into the case. Obviously pumping in 500w of heat into the case is not the most ideal, but I am thinking that if I try to take the air from inside the case and pump that through the radiator, it's going to result in increased coolent temp because the air coming into the radiator will hotter from inside the case than outside.

What do you think?
 

EarthDog

Gulper Nozzle Co-Owner
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Dec 15, 2008
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Buckeyes!
You're right on your assumptions...to get the best temps of the loop components, the radiator needs ambient air from outside of the case. That will send the warmed air into the case increasing case internal temps (and VRM temps...) up. Or you can have the radiator pass the slightly warmed case air. This will result in cooler internals, but likely slight increases of the components.

That said, a 280mm corsair radiator will not handle (well) what you want to put in that loop. Your own results in a previous thread showed the 9700K was hitting ~215W during stress testing and ~165W in Cinebenech... add that to the 225W (stock) 2080 Ti and you have anywhere between 390 and 540W. I'd go at least 360mm worth of rad...especially if you have slow arse fans without a lot of static pressure. I don't know which corsair rads you are talking about, but I hope they have a low FPI for the fans you want to put on it (which won't help that 280mm radiator capacity much).
 
OP
S

SPL Tech

Member
Joined
Nov 28, 2006
You're right on your assumptions...to get the best temps of the loop components, the radiator needs ambient air from outside of the case. That will send the warmed air into the case increasing case internal temps (and VRM temps...) up. Or you can have the radiator pass the slightly warmed case air. This will result in cooler internals, but likely slight increases of the components.

That said, a 280mm corsair radiator will not handle (well) what you want to put in that loop. Your own results in a previous thread showed the 9700K was hitting ~215W during stress testing and ~165W in Cinebenech... add that to the 225W (stock) 2080 Ti and you have anywhere between 390 and 540W. I'd go at least 360mm worth of rad...especially if you have slow arse fans without a lot of static pressure. I don't know which corsair rads you are talking about, but I hope they have a low FPI for the fans you want to put on it (which won't help that 280mm radiator capacity much).

I got a Corsair XR5 280mm. I chose the thin option since I know the low static pressure of these fans cant handle a thick radiator. The CPU wont be using that much power in real world gaming. I suspect I am looking at more like 100w or less in most games. The GPU will for sure pump the most heat. However, right now I have an overclocked 1080Ti and I am running a single H80iv2 which is a thick 120mm radiator. It can handle the GPU quite well actually and I usually only have to run about 70% fan on a 2,000 RPM fan to keep the temps at 55-60c or below (GPU) and coolent temp around 47C. So I figured getting a radiator that is more than double the size and only adding a bit more power with the 2080ti and CPU would be okay.

I could extend the loop out to add a second, single 120mm radiator on the back, although that would make the loop way more complicated. I already know I'm going to have lots of pains trying to bend these acrylic tubes around in circles for the first time. I could also add two more of the same fans on the back of the radiator to have a push/ pull configuration, although I am not sure how much that would actually help. Seems like I would just double the noise for not a lot of benefit, but not sure.
 

EarthDog

Gulper Nozzle Co-Owner
Joined
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Location
Buckeyes!
Thick and thin are part of it......... FPI is another........which the specs say 16 FPI. That isn't terribly dense, but you'll want good airflow over that single rad for best results.

A THIN 280 isn't going to cut it even if your CPU is at 100W and the GPU 225. That's still over 300W load. While it will work fine, I'm not sure you'll be pleased with the temperatures after that loop saturates...especially the CPU. When you say add a little more to the 1080ti with a 2080ti and CPU, you are literally adding ~50% more wattage to cool. From ~225W (1080ti alone) to ~325W+ (2080Ti and CPU).

47C coolant temp... wowzas! :shock:
 
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bassnut

Premium Member
Joined
Aug 16, 2009
In through the front and out through the top and back load up that case with fans ...... that being said you are way short on rad for the loop you have planned by 50 to 70% for good temps I think you will be disappointed in your temps. If I was you I would be looking at something like the UT60 rad in a 280 version, if such a beast exists especially if your stuck on using low speed fans, as already mentioned.

Ut45's ..... https://www.overclockers.com/alphacool-releases-five-new-radiators/
 
OP
S

SPL Tech

Member
Joined
Nov 28, 2006
What about adding a single 120mm on top or on the back of the case? I am not sure which would be preferable over the two--back or top.
 

EarthDog

Gulper Nozzle Co-Owner
Joined
Dec 15, 2008
Location
Buckeyes!
I dont think it will make much difference honestly. You may have to test and see what works better...
 

bassnut

Premium Member
Joined
Aug 16, 2009
You're limited by your case. All you can do is try. What I would do if you have not bought the parts yet is get a thicker rad and better fans 4 basic batb fittings and a couple feet of flexible tube. Lay out your loop and use the flexibletube for the run to and from your 120 rad and see what you like best. You can drain the loop and replace the soft tube once you're happy with the loop. Bling is nice to look at but more often than not hurts performance.
 
OP
S

SPL Tech

Member
Joined
Nov 28, 2006
I cant run a thicker rad because it wont physically fit in the case. This is a mid tower case, not a full size. Plus those 1250 RPM fans cant handle a rad that thick I suspect. It wont be able to push the air through. I could add another 240 or 280 to the roof, but the thing is the case only has an open exhaust hole for one 140mm fan so half of the rad will be blocked. So not sure if it's worth it to do that or just run the 120mm.

Also, btw i run a 1080Ti overclocked off a single 120mm rad and it works fine, so I would think adding another to the 280 would help. The coolent temp at the moment gets to 47C, but I also have the fan at only 1500 RPM and its a single 120mm fan.
 

bassnut

Premium Member
Joined
Aug 16, 2009
Hey it's your build do what you're going to do. You asked for advise we gave it. I hope it works out for you, let us know.
 

Mizzery

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Jun 9, 2002
Location
Troy, NY
As someone who recently built into an nzxt case with a restrictive front intake like that - get more powerful fans. I've got a 280 up front and a 120 in back and I'm not happy with my temps using low speed, low static pressure fans.
 
OP
S

SPL Tech

Member
Joined
Nov 28, 2006
Well I got it built. 50C water temp running Superposition on loop with the fans maxed out. I need more radiator power. I bought a 120mm for the back. I hope that will help a bit. I am not sure what else to add. I am not changing the fans as this is a Corsair RGB build so I need the correct RGB fans. RGB is the focus of the build, not performance, but clearly I want the best performance I can get with the fans I am going to use.

I could add a 240mm rad on top, but the issue is the top of the case only has holes for a single 140mm fan. So half of the rad would be blocked essentially. Not sure how useful it would be.
 

bassnut

Premium Member
Joined
Aug 16, 2009
Why not add a 140 rad as well up top or a good 120 putting a 240 up top is pointless if half is blocked. Putting high speed fans on a low fpi rad is not really going to help your issue much. You are limited by your choice of cases and the rgb fans. Nouse blocker does make an ELoop rgb fan but I doubt you'll see a noticable impact on your temps of the expense of the fans. Right now you are asking a small rad to cool to much.
 
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OP
S

SPL Tech

Member
Joined
Nov 28, 2006
Why not add a 140 rad as well up top or a good 120 putting a 240 up top is pointless if half is blocked. Putting high speed fans on a low fpi rad is not really going to help your issue much. You are limited by your choice of cases and the rgb fans. Nouse blocker does make an ELoop rgb fan but I doubt you'll see a noticable impact on your temps of the expense of the fans. Right now you are asking a small rad to cool to much.

I can add a 140 up top, but that will create two issues:

1. It will be hard to fit a fan on the 140. The mobo VRM heatsinks get in the way. With the 140 mounted up top, I have 1/2cm between the block and the VRM heatsink. I might be able to fit a 120 fan on it, if I offset it to the left side and modify the fan a bit.

2. I wont have any fans in the case anymore that arnt pushing air through the rads. The case has options for four fans: 2 140s up front, 1 140 on top, 1 120 on back. With this arrangement, all 4 fans will be mounted to a radiator. Not sure if that's a bad thing or not.
 
OP
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SPL Tech

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Nov 28, 2006
The 120 helped more than I expected. Went from 53C to about 44C water temp. GPU temp 61C to 52C. That's a lot for a little 120mm. Also, it's noticeably cooler in the case now that I have a rear exhausting radiator removing some of the heat. It would be nice to get a 140mm on top.
 

EarthDog

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Buckeyes!
You've essentially increased your radiator size by ~40%... makes sense there would be notable improvements.

How long is your testing for temps, BTW? It should be for AT LEAST 30 mins so all the loop saturates and normalizes.
 
OP
S

SPL Tech

Member
Joined
Nov 28, 2006
You've essentially increased your radiator size by ~40%... makes sense there would be notable improvements.

How long is your testing for temps, BTW? It should be for AT LEAST 30 mins so all the loop saturates and normalizes.

More than that. I am gaming for a few hours. I wonder if its worth it to try to add a 140 on top. It's just getting pretty tight in there with these many hoses and rads.
 
OP
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SPL Tech

Member
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Nov 28, 2006
Changed the case to a Corsair 550x. Added a 360mm, 280mm and 120mm radiator. Dropped water temps down to 40C. GPU is about 49C in game. Much better.
 

EarthDog

Gulper Nozzle Co-Owner
Joined
Dec 15, 2008
Location
Buckeyes!
Changed the case to a Corsair 550x. Added a 360mm, 280mm and 120mm radiator. Dropped water temps down to 40C. GPU is about 49C in game. Much better.
What did you gain from this change? Gpu temps were already below the point of dropping bins.