Lian Li XL - 3rd Rad vs 3 intake fans

[LewisN2]

Ok guys, so i was wondering if you could all give me some advice

I have a Lian Li XL with
Bottom Rad : 1 X XE (intake lian li 120mm fans on)
Top Rad: 1 X PE (exhaust lian li 120mm fans on)
1 Intake fan at the back of the case (blowing air into top rad)

what would be the most beneficial for the side space of the case:
PE Radiator (Noctua Slim fans) which is my current set up vs 3 full sized intake fans with no rad?


My friend seems to think i should get rid of the side rad and allow for extra airflow to the top rad (he thinks it is being choked of air), i personally think the 3rd rad with the slim fans is more beneficial. Does anyone have any experience with this?

Is it possible that if the top rad is being choked of air, that it is heating up my loop? the XE due to the thickness doesnt allow for much airflow and neither does the side slim fans really, but i do have the fan at the back blowing cool air, and there is atleast still some airflow.

it is worth noting that i did test without the side panel on (to allow for max airflow) and it seemed the tempratures did not change by a noticeable amount.

5800X3D
RTX 4090
EK D5 Pump

 

[LewisN2]

If the side rad fans are intake then the rear as intake blowing directly at them might be causing you some flow issues. Have you tried flipping that one alone just to see what difference that makes?

What's the goal here and what components are you cooling? Are you bothered by temps/noise and want to improve that in some way? Have you checked that there's at least some coolant flow if you're not using a D5 with that many rads/blocks?

I'm running side and bottom intake 60mm rads with a rear exhaust fan and don't have any thermal issues with my 13600k and 3080ti so unless you've got some really high power components you should be able to manage temps easily with 3 rads.

Hi yes i do have some pretty beastly parts - i have a 4090 and 5800X3D, and yes i have a D5 pump running at 100% when gaming so flowrate is not an issue

Now my temps and sound to not particularly bother me and they are acceptable.

My goal is just to find out if my temps would be better with the rad on the side (with slim fans), or to have 3 full sized intake fans blowing cooler air into the case.

It is possible that the back intake is causing flow issues but most likely its blowing air directly into the top rad.

 

[LewisN2]

ull bottom intake

As someone who has worked with CFD modelling I can tell you with certainty that it absolutely does not work like that. Providing fresh air may be beneficial to the exhaust rad up top, but if you're stopping the middle rad from exhausting heat then it's likely to be a net loss.

If you don't have any problems and are just chasing a few degrees then the only way to test it on your specific setup is to just change stuff and see what difference it makes as you've ruled out all the obvious stuff that might be causing problems. Or you could just call it job done and be happy with a quiet system!

so i tried flipping the back fan to an exhaust, and it actually made my tempratures ever so slightly worse believe it or not. i guess this probably means the back fan as an intake is not conflicting with the side rad intake.

 

[LewisN2]

There is also another option, i get a slim rad, and then put full fans on there to maximise airflow