Optimal distance between fan and rad?

t1rhinot1rhino Toronto
edited November 2003 in Hardware
I don't really know if this has been discussed before, but what is the optimal distance between a fan and the rad for watercooling?
Fan touching rad can increase resistance, but too far away can lower pressure?

What do you think?

Comments

  • DanGDanG I AM CANADIAN Icrontian
    edited November 2003
    I've got mine screwed right to the rad with a ghetto shroud, black electrical tape making a nice tight seal around the edge so all the air goes through the rad. Works well for me.
  • Geeky1Geeky1 University of the Pacific (Stockton, CA, USA)
    edited November 2003
    The shorter, the better.
  • TheLostSwedeTheLostSwede Trondheim, Norway Icrontian
    edited November 2003
    Geeky1 had this to say
    The shorter, the better.

    The opposite is actually correct. The closer a fan is to a radiator or a heatsink, the less flow area you have. The motor/spindle on the fan is a dead sone in the flow. Theoretically, if you have a shroud that is close to 100% air tight, you can have the fan as far away you want. But in a case where space is also a factor, between 2 and 4 inches will do just fine Rhino. Make that shroud as tight as possible though.
  • t1rhinot1rhino Toronto
    edited November 2003
    Okay. Here is my plan...

    I want to build a small external box for my watercooling setup.
    The width of the box should be no more than 7.8".
    I plan on using 1/2" material, leaving me with 6.8" inside.
    I plan on sandwiching 2 120mm fans between 2 of these rads (slightly modded).
    2-302.jpg

    Fan width = 1".
    Rad width = 2".

    So I should have 2.8" of space left. Therefore, I can create 2 shrouds, each 1.4".

    Atleast that's the plan. In the end, I hope to have something that works like this. http://web.wanadoo.be/ocyeti/site/wc.htm
  • t1rhinot1rhino Toronto
    edited November 2003
    This is a very simple diagram of my idea.

    I am concerned though, that the fans won't have enough power to push and pull through 2 rads. :scratch:
  • TheLostSwedeTheLostSwede Trondheim, Norway Icrontian
    edited November 2003
    Looks like a great idea and have it externally is even better.

    DOnt worry, the fans will be able to move air through it as long as it has distance between the fins. BTW, what rads are those? GM heater core? Can you use 2X120mm on each side?
  • TheLostSwedeTheLostSwede Trondheim, Norway Icrontian
    edited November 2003
    Sexiest Shuttle i have EVAR seen. Dang!
  • t1rhinot1rhino Toronto
    edited November 2003
    It's a GM core. Looks exactly like the Black Ice Extreme II. :)
    Do you mean like this?
  • TheLostSwedeTheLostSwede Trondheim, Norway Icrontian
    edited November 2003
    This is my rad with 2X120mm on one side if this is what you meant.
  • edcentricedcentric near Milwaukee, Wisconsin Icrontian
    edited November 2003
    Fans don't like back pressure or turbulance. Standing the fans back a ways will help as long as the shroud is very tight. Adding straightening vanes between the fan and rad can help.
  • Geeky1Geeky1 University of the Pacific (Stockton, CA, USA)
    edited November 2003
    Mackanz, yeah.... I read what you said, then I read what I said, then I re-read the title. I thought t1 was asking about the distance from the water block to the radiator for some reason... *sigh* :rolleyes:

    In terms of distance from fan to radiator, Mackanz is correct- to an extent. You want as much distance as possible, but not so much that the airstream from the fan is extremely diffuse by the time it reaches the radiator.
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