Air cooling question.

[o0OBruceLeeO0o]

Does it matter how many intake/exaust fans I have as long as I have the same amount of intake cfm and exaust cfm? Also why do they need to be the same amount? If they are both reasonably high whats the difference? Any help is appreciated. thanks!

 

[AZZKICKER]

its better to have more blowing out then blowing in
like if you have 175 cfm in it would be good to have 200 CFM out

 

[Silver]

And I kind of like a little positive pressure (to insure air to all components rather than a direct in/out path. Different strokes. As long as you are in the general range of equality then I suspect you will be all right.

I am presently running 1 60cfm AC in the front of the case, with three 21cfm's on the side cover (all blowing in). The two psu fans plus two additional give me roughly 120 cfm in and 80 cfm out. The slot below the vid card has the cover removed in order to take advantage of the positive pressure in assuring good cool air flow to the vid card.

 

[Dark Disciple]

You want to try and have about the same air-flow in both directions. But, if this is impossible to acheive, having a slight vacuum is better than the alternative (more air moving into the box than exiting it).

 

[AZZKICKER]

you want more blowing out than blowing in

fresh air come in that slot you have open right onto your vid

ALWAY have more out then in

its harder to push heat out than it is to push cooler air in

all your doing is warming up your cool air coming in by haveing more in than out

trust me

im the air master

 

[o0OBruceLeeO0o]

Ok cool! now i dont have to cut a hole in my window ... My case has 3 80mm front fans 2 80m back and 1 92mm back. If I was to add a blowhole that would make it perfect right? If thats a little too much I can get the louder panafolo fans in the front and the quieter in the back. Thanks for the help guys!

 

[Silver]

I would definately listen to the other guys as I run water and water/pelt cooling so my internal case heat load is minimal. Take Care.

 

[lazerin]

Here's the low down on the three different possible types of air flow in your case:

Positive Airflow - More air going in than out. In this setup, there will be less dust accumulating in your case because there is slight positive pressure, which pushes air out which keeps dust out.

Neutral Airflow - Equal amount of air going in and out. This is the same as having the side of your case open. This ensure a more or less continuing flow of fresh air getting in and out of your case. Dust is moderate in this setup.

Negative Airflow - More air going out than in. Slight negative pressure is created inside your case with this setup, which can cause a great build up of dust. This is because with negative pressure, air tries to enter from every hole in the case, which brings dust into all the little cracks in the case. However, the upside to this setup is that it will evacuate all the hot air in your case pronto, leaving the case at a cool temp all the time. I highly recommend this setup, and I use it myself.

To prevent dust buildup, cover up all the holes and cracks in your case except the fan intakes. Then, attach filters to all your intakes. This will ensure a dust free case for some time.

Hope this helps

 

[Yodums]

I sorta like positive airflow since as Silver said you are getting more cool air to the hardware. But however both ways are affected:

Negative: You are sucking out alot of air but you still need lots of CFM to push cool air in to make up for the negative pressure.

Positive: Very difficult for cool air to over ride the hot air around the CPU Area without good exhausts there.

 

[Robin Hood]

I was running an in/out ratio of 5/3 but lowered to 4/3 - too much case pressure made my YS-tech 120x38 (exhaust) very noisey.

 

[RideGuy]

Lazerin already started this depate with a poll.http://forum.oc-forums.com/vb/showthread.php?s=&threadid=106027

I voted neutral


Ride

 

[o0OBruceLeeO0o]

ok, thanmks for the info guys! How dusty does it get? anyone have a pic of there negative airflow case (that hasnt been recently cleaned) ?

 

[lazerin]

It won't be dusty if you cover up all the gaps that you dont want as intakes, and put filters on the actual intakes. You can use pantyhose as filters (I use black pantyhose) and they work great.

If you can't be bothered, with moderate negative pressure, say 3:1 then you will need to clean your case once every month or so.

 

[o0OBruceLeeO0o]

It won't be dusty if you cover up all the gaps that you dont want as intakes, and put filters on the actual intakes. You can use pantyhose as filters (I use black pantyhose) and they work great.

If you can't be bothered, with moderate negative pressure, say 3:1 then you will need to clean your case once every month or so.

what other holes will there be in the case to cover up?

 

[o0OBruceLeeO0o]

what other holes will there be in the case to cover up?

bump that

 

[lazerin]

what other holes will there be in the case to cover up?

You'll be surprised. For example, the space between your cd drives. The gap in the edge of your side panels. Gaps in pci slot covers at the back of your case etc.

Every little gap you can find. Just tape them up or something.

 

[o0OBruceLeeO0o]

You'll be surprised. For example, the space between your cd drives. The gap in the edge of your side panels. Gaps in pci slot covers at the back of your case etc.

Every little gap you can find. Just tape them up or something.

eeek, I am leaning towards positive air pressure now lol

 

[CyberFed]

i run about 100 cfm blowing in and about 120'sh blowing out (see avatar) the top blowholes have higher powered fans that pull air, my temps dropped 3C when i actually put my side panel on vs just leaving it off alltogether. Hope that helps a bit

 

[lazerin]

When I have my case on, my temps are also lower than when my case is open.