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Case airflow question

Discussion in 'Overclocking & Cooling' started by Scougar, Feb 3, 2011.

  1. cameraheaven


    Joined: Jan 15, 2011

    Posts: 48

    Location: Aussie near Highwycombe

    Because Scougar want it to sound like a PC!....Not a F15 on the number 1 catapult!
    You can actually get to the stage were no matter how much air you blast at it ...cooling differential doesn't move much any more. OLDFART!...Your mouth in gear first comment of "I'm afraid you have it all wrong" did make me laugh!...Let me explain..... All the laws that apply to fluid dynamics , apply to air, the property's and characteristics are the same. Forgetting about maximum critical flow limits for a given tube/hole size.......The difference between a 1" tube and a 2" tubes ability to deliver a fluid is 8 times.....that is, a 2" tube has the ability to deliver or exhaust 8 times more fluid/air. "FACT!"

    Of course a 180mm fan will eat a 120mm fan for breakfast......It's not rocket science!!!

    But when you change a fans characteristics to perform a given task (Penetrator) regardless of size......there has to be a design trade off....Better focus of air stream means you have to take a hit on DBA (noise) or CFM (volume) or even both. The golden approach is be to make (pick) the heatsink that's more efficient for the air to act upon..........And the magic bullet is getting the hot air "OUT" as quickly and efficiently as possible, not making a computerized hovercraft

    Aussie Allan


    Joined: Jun 19, 2004

    Posts: 6,506

    Location: n/east-the toon

    Hi AA, lol not the baffle me with science ploy > Fluid Dynamics and even rocket sience, yes if case designers took that into account, its only the last couple of years where case manufacture's have taken case air flow into thier design of the interior, etc IE: Lian-Li. But there is still quite alot that stick to x1 exhaust fan / x1 intake fan both the same, one or two have installed a faster exshaust fans. If you look at the front fan in most case's its blocked by the HD bays, in some you can remove half to help improve air flow. So when you think about it the top fan has a lot of work to do, as the air flow is hampered by the HD bays as in scougars case. So fitting a fan in the side panel would work alot better as its blowing straight onto the motherbroad, OK it does not have to be a 180mm, but if he measured it out properly he could have the fan blowing onto the CPU cooler area which would help with the temps a Prolimatech Blue Vortex Blue Wings 140mm Fan looks the job.

    Prolimatech Blue Vortex Blue Wings 140mm Fan > side panel
    - Dimension: (L)140mm X (W)140mmX (H)25mm
    - Bearing Type: Sleeve bearing
    - Rated Voltage: 12 VDC
    - Operating Voltage Range: 7~13.8 VDC
    - Rated Current: 0.2 Max.Amp
    - Rated Power: 2.4 Max.Watt
    - Rated Speed: 1000±100RPM
    - Airflow: 87 Max.CFM
    - Noise Level: 18.1 dBA
    - Net Weight: 162 Gram
    - Connector: Terminal Connector(3-pin plus 4-pin molex)

    Yes l said put a 180mm fan in the side panel but the would cool a greater area on the mobo again improving temps, he could use the 180mm thats in my case 180mm 100cfm 18dba silent or the penetrator 2 speed 700rpm:80 cfm 16dba silent mode > 1200rpm:130cfm 34dba. He could turn the front fan to exshaust, so that would give him two exhaust fans and he would lose some through air presure. But he could also fit x2 120mm Vipers on fan controller, saving him the job of cutting the 120mm front mounting hole or a side panel fan, so he could adjust the air flow when need be.

    Your bringing Fluid Dynamics, into it, but have a look at my case nothing fluid about it the FT01 x2 180mm intake fans-700rpm 100 cfm 18dba-x1 toprear / x1 front bottom. x1 120mm top rear exhaust 900rpm 35 cfm 18dba, just looks a standard case inside nothing special see photo, even the rear looks like any other case. But it works on positive air pressure with the top fan doing most of the cooling, hot air exhausting out the lower back due to a small vent 25mm W x 80mm H drilled with 4mm holes + vented PCI brackets quite a few case have them and the rest anywhere it can due to the high air pressure helps keep the dust out. As for sounding like F15 on take, the fans are very silent and l wouldn't call 100cfm a trade off as you put it and if you think about it the top rear fan 100 cfm is pushing the hot air down not up as it should giving the the 120mm 35cfm exhaust fan a hard time as it interupts its air flow and they are very close together. I used a H50 with a Viper-push / Apache-pull which worked very well as the top 180mm fed it cool air. If l had something like a Akasa AK-Artic Frezer 13, l would have mounted it facing down if possible going with the main air flow + turned the 120mm round to intake, to see if it cooled any better. Yes even the 180mm pentrator 2 speed low > 700rpm 80cfm 18dba high > 130cfm 34dba giving him chose of cooling when need be, but there's still a quite a few 120mm fans round the 34dba if you want good cfm.

    But l have given scougar of couple of ideas for cooling 1- sidepanel fan 140mm or 180mm or 2-vipers on a fan controller.
  3. Scougar


    Joined: Jan 30, 2007

    Posts: 12,073

    Location: PA, USA

    Interesting reading chaps :)

    I installed the Scythe Kama Bay today. Didn't have much time as it was after a horrendous start to the day, but got it in there. Currently sat at max of 67 on the hottest core after an hour and twenty minutes and it hasn't budged for the past hour. This is with the case side ON! So basically just as good as with the side off, although it is a few degrees cooler in here at the moment (3 to 4 cooler). The included kama bay fan is pointing directly at the cpu cooler, although I want to change the fan for a better one when possible. It really isn't perfect though as the IDE cable is directly in the air flow so I will have to move my HDD's around or change my DVD rom drive to a sata unit.

    The other changes I made where to change the rear fan for an Enermax TB Silence 12cm fan, because I sold all my ambers and had to have a fan on there so this is only temporary. Also I had to remove the fan controller (d'oh) as I no longer has enough spare bay's to mount a 5.25 inch controller in. I will have to find a 3.5 inch controller.

    Didn't get a chance to try the blowhole.. not sure I will anytime soon, but will do it when I get a moment without the baby/wife combo that doesn't need me or the PC lol.
    Last edited: Feb 16, 2011
  4. CurtGuven


    Joined: Feb 16, 2011

    Posts: 30

    One of the best tricks in the book!

    Make sure your front intake is not blocked by anything either - my case (CM690) is poorly designed as it cuts off airflow from the front fan with the hard drive bays - if you can, stick an fan in your 5.25" bays pulling in air, that way you get air flowing directly through the case, through the CPU fan and out the back.
  5. Scougar


    Joined: Jan 30, 2007

    Posts: 12,073

    Location: PA, USA

    That's precisely what I did yesterday with a Scythe Kama Bay 120cm feeding directly onto the CPU cooler. Only downside is I lost my 5.25" fan controller and the IDE cable is semi is directly in the airflow (annoying).

    I'm still running a slow fan on the back , so want to replace that soon, which may happen if I can change the front bottom fan to an air penetrator or similar.