Airflow observation

Supa Koopa

Supa Koopa

Supa Koopa

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Joined
23 Jan 2007
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167
Location
Wakefield
I was checking a few things over on my PC last night and noticed that there doesn't seem to be much air moving through my top rad. It's a Nexxxos XT45 with 3 SP120 quiet editions. Even running at full speed (1,400rpm) the scientific test of putting your hand below doesn't seem to yield much air flow. If you put your hand on the other side there seems to be losts of turbulence, like the air is just boucing back and not actually going through. Now I've checked the fans and they are mounted the right way round, I've checked the rad and there are no blockages, this was with the side of the case off so no positive pressure build up. The front 280 is totally fine and there is loads of air moving through it.

Is this normal, a side effect of the XT45 or I'm losing my mind?
 
hmmm weird im using a the same rad but 280mm and using af140's and have no problem mine are in push pull although my fans are supposedly no good for radiators and work fine. prob a bad thing but i used my e cig to see what the air flow was like in the case with one exhaust and it's good no turbulence at all even with my fans only running at 400 rpm
my top rad is a alphacool 30mm thick 240 with sp 120's in push intake and no problems with that either?
sorry i can't help you i take it you have no bent fins or anything similar?
are all your fans set the same rpm?
 
Yeah it's really strange as my XT45 280 is absolutely fine. If it was the same I wouldn't have questioned it. I've had a look at the fins and they seem okay and the fans all run at the same rpm.

I like the e cig idea...! :)
 
Kaku - No dust filter. The 750d has a kind of magnetic mesh that you can remove, which I did for the tests. No account to post any pictures, sorry.

Almighty15 - I thought Corsair SP120's were good for rads, it seems so everywhere I've read?
 
No they're not, I told another guy on here to buy the £4 Arctic Cooling F12's as he was running Notua Fans ( £20 a pop )

He followed my advise and ended up with much cooler temps and less noise.

Air flow is the most pointless metric when picking a radiator fan.

Static pressure is king.
 
SP120QE's are perfectly fine, especially on a low fpi/low thickness rad like an XT45.
They're not 'crap' fans. I've had them running on AX rads and there haven't been any issues with airflow/pressure/temps.

Dude, seriously give the absolute opinion=fact stuff a rest.
 
Yeah i don't buy the BS of it's a bad fan.
Also just want to point out im also using the 750D i have the front as intake and the top intake and exhaust 1 fan rear.
 
I run SP120s, performance editions though. Chosen for aesthetic purposes - I don't have any performance data vs. other brands unfortunately - but they seem to do OK.

Can you get better for the price? Probably, they are reasonably expensive
 
Uncle Petey said:
SP120QE's are perfectly fine, especially on a low fpi/low thickness rad like an XT45.
They're not 'crap' fans. I've had them running on AX rads and there haven't been any issues with airflow/pressure/temps.

Dude, seriously give the absolute opinion=fact stuff a rest.
Click to expand...

Go and visit martinsliquidlabs and read his fan articles.
 
Uncle Petey said:
He has a lot of fan articles. Maybe you could link to the relevant one?
Click to expand...

Not while at work as the site is blocked ( But OCUK forums aren't :confused: )

He does a massive group test and there's a lot of poor results from fans that you would not expect!

In this test the little £4 Arctic Cooling F12's dominate fans costing 4x as much.
 
I'll have a look through later.

I had a couple of F12s a while back and yeah, they are great for the money. That doesn't make the SP120's crap though and they should be plenty adequate for this particular task.

When I used the SPQE's on AX rads, I could feel the air movement from a good few feet away and actually used it to dry the odd jumper that couldn't go in the dryer every now and then :D
 
Strange, I would have thought the front of a 750D would be more restrictive than the top. Do you have intake or exhaust at the top? Tried a tissue paper test to check the airflow?
 
Sorry I didn't mean to cause a bun fight. :)

Front is intake and top is also intake with rear exhausting. My logic was fresh air over the rads and hot out the back. What's a tissue paper test? I'm guessing a strip of tissue paper put in the flow to see if it moves?

I'm at a loss as I really can't see how there would be such little airflow at 1,400 rpm through the rads and so much bouncing back up, compared to the front that has such a definite force of air at only 800rpm. The xt rads are 11fpi so should be getting loads through it and are only a couple of months old so not full of crap. Now I'm starting to think if this is the cause of my comparatively poor temps. Everyone keeps saying (on here as well) that I should have enough rad space to cool what I have, but if the front is doing most of the work it could be a reason.
 
Intake. fans up against the top pushing through the rad.

That's what I find strange I can feel the air from the fans so they are working it's just not going through the rads, it's as if there is some restriction there, which there isn't.

Watercooling is a black art that I seem to struggle with. :)
 
No Sorry I guess I made it a bit unclear.

Front rad intake - Top rad intake - rear 140mm fan exhaust. All rads then get fresh cool air and there is positive pressure.
 
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