New cooling system modifications and math.

TimTim Southwest PA Icrontian
edited March 2004 in Hardware
Made some good progress tonight. Took apart my Powmax ATX tower case, and did some cutting. Behind the front cover, I chopped out all the little grille lines that weren't needed to bolt a front fan in the computer. Don't think it helped much, but it certainly didn't hurt.

Then I pulled out my 2 80mm case fans, and with some damp paper towels to catch the dust, I Dremel cut out the fan cover plates with all the tiny 1/8" holes in them. Shattered a total of 11 Dremel cutting wheels in the process. Those things are FRAGILE!!!

Here's my math on the rear fan cover plates.

Stock, it has a total of 272 1/8" holes for the air to get out. Gross surface area of the holes is 3.33 square inches.

Once the cutting was done, I had 2 wide open 3" diameter holes. Gross surface area - 14.13 square inches! AIRFLOW!!!

But that's a gross number. It doesn't take into account that there's a 1-1/2" circle blocked in the middle by the motor and fan hub.

So, with the surface area of the motors subtracted, I now have 10.6 square inches for the fans to work with effectively.

That's a 318% increase from stock.

As soon as I started the computer and checked the hardware stats, I saw that the case fans has picked up around 200 rpms each. The CPU fan gained about 100 rpms.

Case and CPU temps also dropped. It used to idle with the case at 28 C. Now it's 24-25. Idle on the CPU was around 45, now it's 42.

While playing video, after a few minutes the case would get up to 35-36 C, now it's more like 30-31. CPU temps used to get up to 61-62 after about 8 minutes, now it peaks around 56 C.

So it has been a definite improvement. A successful project.

Comments

  • a2jfreaka2jfreak Houston, TX Member
    edited March 2004
    Yes they are fragile.

    Definite improvement in temps.
    Once you get a new HSF you should be doing even better.
    Tim wrote:
    Shattered a total of 11 Dremel cutting wheels in the process. Those things are FRAGILE!!!

    ...

    Case and CPU temps also dropped. It used to idle with the case at 28 C. Now it's 24-25. Idle on the CPU was around 45, now it's 42.

    While playing video, after a few minutes the case would get up to 35-36 C, now it's more like 30-31. CPU temps used to get up to 61-62 after about 8 minutes, now it peaks around 56 C.

    So it has been a definite improvement. A successful project.
  • profdlpprofdlp The Holy City Of Westlake, Ohio
    edited March 2004
    Impressive math skills! My dad, who taught HS Math for 50 years, would be proud of you. :respect:

    This is the first time I have seen specific before & after temps from such a mod. I'm going to have to check my rigs to see if any of them can be improved the same way.
  • Geeky1Geeky1 University of the Pacific (Stockton, CA, USA)
    edited March 2004
    I'm too lazy to do all that math :D but it doesn't surprise me at all. Especially if the powmax case has the REALLY cheap stamped fan grills that I think it does. The ones on Antec/Chieftec etc. cases aren't as bad, but they still do more harm than good. I mean, after all... how often do you go sticking your hand in fans? (well, unless you're me, anyhow... but I don't count :D)
  • DragstkDragstk Syracuse, N.Y.
    edited March 2004
    Tim, 11 blades broken :hair: You are wearing glasses, when your cutting, right? :cool:
    In my 3 computers I've cut 13 holes, and broken 2 blades. I just wore them out.
    Just go slow, let the blade work. Very little pressure on the Dremel, keep the RPM's up. The tighter the curve, try tipping the blade.
    Cutting is good, long as it's not your skin
  • muddocktormuddocktor
    edited March 2004
    I also imagine that the noise from the fans is a bit less too, Tim. I definitely noticed that quite a while ago when I first started cutting those cheese grater fan holes out from where my fans mount. More airflow+less noise=good! :D

    Dragstk, it's real easy to shatter the wheels when cutting those cheesegrater hole sections out, more so than just cutting a hole to mount a case fan in a solid section of the case. The more you use that dremel, Tim, the better you will get with using it without shattering the wheels. Like Dragstk said, nice and easy does the trick.:)
  • TimTim Southwest PA Icrontian
    edited March 2004
    Yes, I was wearing safety glasses. After the first wheel exploded. I've used my Dremel a lot for porting cylinder heads for my cars (1970's Chryslers) in both iron and aluminum. But that is all done with carbide cutters. Never had to use the cutting wheels that came with my Dremel set 4-5 years ago. Last night most of them got used.

    I wouldn't say the fan noise is quieter, but it's different.

    After I saw the fan rpms had increased, I took one of the cut out grilles and held it in its original place. Rpms dropped. Removed it, rpms went back up.

    I may bolt an extra 80 mm fan in the front of the case, but I'd have to extend the power wires and connect them to one of the unused plugs on the power supply. There's not really a lot of room in the front bottom of the case for air to come in.

    I had thought of placing the extra 80 mm fan up inside the case under the CD drive so it's blowing directly across the memory and onto the CPU.

    Still need to buy a good copper heat sink, though.
  • TimTim Southwest PA Icrontian
    edited March 2004
    I gave it another test. I re-encoded a video I'd made recently. It took about 5 minutes, and with the processor at 100% the whole time, the case temp stayed at 30 and the CPU didn't go over 58.

    Once the encoding was done, it dropped 5 degrees ( CPU ) in less than 15 seconds. Then came down the rest of the way to normal temperatures.
  • DragstkDragstk Syracuse, N.Y.
    edited March 2004
    Oh, I realize the discs break easily. I have broken my share of them. :D I am a hard core model builder, and have been since the 4th grade. So, I have cut a lot of plastic.
    I was just concerned about Tim,with that many disc breaking, as I have been hit by a couple :sawed: when they came apart.
  • GHoosdumGHoosdum Icrontian
    edited March 2004
    Tim wrote:
    I've used my Dremel a lot for porting cylinder heads for my cars (1970's Chryslers) in both iron and aluminum.

    I haven't been over on Slantsix.com in a while, Tim... how's your Duster project going? And is the Valiant still alive?

    By the way, I watched your videos with the Aspen R/T a while ago... that is a SWEET car.
  • TimTim Southwest PA Icrontian
    edited March 2004
    My Duster is in the same condition it was 15 months ago - untouched.

    I still have the Valiant, but it is semi-retired. I drive it once in a while. At night. The inspection is a year out of date!

    This spring I plan to swap the Valiants' drivetrain to the Duster. Everything will bolt right in, but first I have to buy a good clutch. And that's the holdup right now, with money and bills and jobs and getting laid off.

    I WILL be at the Pittsburgh /6 race in July - it's at my home track!
  • GHoosdumGHoosdum Icrontian
    edited March 2004
    You're still doing better than me with the project cars, Tim... I don't even have one right now. :(
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