Working out Airflow/Fan Direction

[Alphanos]

I'm going to be building a new system, most likely in an Antec SX1040 case, and am trying to work out proper airflow in my case. I would like to put on a side panel with a side fan hole, but this introduces some airflow problems. I don't really want the side fan blowing in because it would look ugly to put a dust filter there, but if I have it blowing out I'll have 4 fans blowing out (2 back + 1 side + 1 PS), and only 2 in (both filtered, reducing airflow). I've heard this will cause more dust problems as air will get sucked in from any cracks due to low air pressure inside the case.

So, is it a viable option to run 2 front + 2 back fans blowing into the case (filtered, reducing airflow), with the PS and side fans blowing out? Would this require that the out-blowing fans churn out more CFM, or is it okay to have a higher air pressure inside the case? I don't know much about this kind of airflow because I've never really built a system before, nor used on with this many fans.

 

[1sikbITCH]

I'm not an expert by any means (I had to ask a similar question a little bit ago) so someone correct me if I'm wrong.

One conclusion I've come to from reading posts here is that since positive pressure is better, if your fans are set up right you'll have air being sucked in from every little crack and space in your case anyhow. This will negate any filters you put on your fans, and so you may as well not have any filters and have your intake = side and front, and exhaust = rear.

Filters or not, your case will still get dusty and need to be blown out with a Can-O-Air every so often.

You can't have air coming and going from all different directions because this will only create turbulance in the middle, which will be very loud and not very efficient. All the air should basically flow in one direction I think and not get hung up fighting in the middle.

 

[0roo0roo]

remember that fans have sh*t in terms of fighting backpressure. blowing air into a confined space counts. cfm spec is for the fan blowing in free air. so to combat this you have to have more fans blowing in then out, or atleast as equal as possible.

just remember fans no good for making vacumns

unless you start stacking fans in series to make em more powerful heh.

 

[1sikbITCH]

Yikes... I guess I'm off to buy a 120 mm for the front of my case. I've got one 80 on the front and one on the side. Then 2 exhaust in the rear + the PSU and one exhaust on top.

Should I get a rheobus and turn down the exhaust fans?

 

[0roo0roo]

don't think turbulance inside your case will make any noise. its doubtful you have fans blowing fast enough to have it happen. its turbulance at the fangrill if the holes are too small/slits too small that makes noise. that and vibration if the fans are not isolated from the metal. i run my 4 case fans at ultra low rpms with wire grills so no vibes anyhow.

 

[PCHPlayer]

You can always use lower CFM fans in back and higher CFM fans in front to balance the airflow.

 

[0roo0roo]

not much point in lower rpm fans in the back. probably help increase resistence of air for the front fans.

 

[PCHPlayer]

Not if he has 3 fans blowing out and 2 blowing in

 

[mechBgon]

I vote for just skipping the vented side panel altogether. Its main benefit would be to provide direct cooling to the video card. Without it, you have a pretty even front-to-back airflow. PCHPlayer suggested a slick filtering method about a year ago, using Airkontrol 4" x 12" HVAC filters behind the SX1000's bezel (more info here).

While we're on the topic, you may find this thread of interest for cooling the top section of the case better.