Delta fan mod

[Godfodda]

I just finished a Delta fan mod trying out an idea for quieting the turbine. (Actually, taking the fan off, I discovered it was a generic, maybe. Galaxy.) My thought was that part of the noise was coming from the fins rotating so closely to the 4 supports that run from the motor to the fan housing.

I used a Sears imitation Dremel and shaved these supports to about 1/2 their normal thickness, taking off the upper part near the fins. At first I thought there was a difference in sound, but I now believe this was due to my ears comparing the fan to the Dremel, which is much louder. I believe it has actually had little or no effect.

Just though I'd drop this out there for anyone who may be interested. I'm also considering removing 2 of the 4 supports just for the heck of it. If anyone has a fan they want to chop up and some way to measure db, I'd be interested in comfirming this.


I have noticed a temp difference since I remounted the fan, but I can't yet attribute it to just the fan mod since I'm trying several things at once. This CPU (the 1100) normally runs at 10+C over case temp. Right now it's 2C over (29 CPU/27 case, ambient somewhere below 21, closed case). But I'm playing with fan locations, case on / case off, fan directions, etc. Will update if it seems the difference is due to the Dremel work, though I don't really see how it would be.

BTW, all temps are 100% load with SETI.

[Diggrr]

I used a bong some time back, and I hacked the shroud off of my Panaflo to mount it recessed into the pvc 'Lip'. I noticed one of it's secrets to quieter airflow was that the fan motor supports are an airfoil shape (cross section) and not square. You might try this too.

Just a thought.

Mod on!

[Godfodda]

Originally posted by Diggrr
I used a bong some time back, and I hacked the shroud off of my Panaflo to mount it recessed into the pvc 'Lip'. I noticed one of it's secrets to quieter airflow was that the fan motor supports are an airfoil shape (cross section) and not square. You might try this too.

Just a thought.

Mod on!

Thanks for the note. As long as I'm chopping away, I'll give that a go before I whack off the two supports.

I'm still getting only a 2C diff in CPU/case temps (29/27), going as high as 3 and as low as 1.5. I had expected that after it ran for a while the temps would be back where they "belonged". I know the case temp is more elevated than before due to poor airflow, but the CPU is cooler. I'm a bit perplexed, really. After I finish messing with a 486 project, I'm gonna pull the cover back off and see what I did. :)

[Yodums]

Originally posted by Godfodda


Thanks for the note. As long as I'm chopping away, I'll give that a go before I whack off the two supports.

I'm still getting only a 2C diff in CPU/case temps (29/27), going as high as 3 and as low as 1.5. I had expected that after it ran for a while the temps would be back where they "belonged". I know the case temp is more elevated than before due to poor airflow, but the CPU is cooler. I'm a bit perplexed, really. After I finish messing with a 486 project, I'm gonna pull the cover back off and see what I did. :)

I believe radio shake sells some external probes which are like a few bucks. All you do is put it on your core and it'll show the temperatures. So you can try that or I have no other idea its that or something is wacked with your internal diode, like some diodes dont even touch the cores.

[Godfodda]

Originally posted by tsunami


I believe radio shake sells some external probes which are like a few bucks. All you do is put it on your core and it'll show the temperatures. So you can try that or I have no other idea its that or something is wacked with your internal diode, like some diodes dont even touch the cores.

I don't think it's a probe problem. After I transferred the CPU from the Abit to the AOpen, the temps were similar (ie: 10 or so C above case temp).

[Yodums]

Originally posted by Godfodda


I don't think it's a probe problem. After I transferred the CPU from the Abit to the AOpen, the temps were similar (ie: 10 or so C above case temp).

Edit: Your CPU temperatures are never that close to your case temperatures and if they were it wouldn't be possible with air cooling.

A Swiftech would not even cool a high end system that much.

[Godfodda]

Originally posted by tsunami


Edit: Your CPU temperatures are never that close to your case temperatures and if they were it wouldn't be possible with air cooling.

A Swiftech would not even cool a high end system that much.

I disagree, and I think others will too. It would be fairly easy to have case and CPU temps near one another, especially with poor airflow.

So is my main system wrong according to you too? Those temps are only separated at the moment by 6C (27/21) but have been about 4-5C apart most of the day. And that's at 170 FSB!

edit: My above statement should show you that it's not only possible, but is what's happening. Case 1 - 21C, Case 2 - 26C. CPU 1 27C, CPU2 28.5C. That's up-to-the-second temp reporting too. :p

[Diggrr]

Hey Godfadda,
You don't have a duct to the hsf fan? In that case it's perfectly sensible that the cpu would go down with the improved fan, and the case temp would go up. It's removing more cpu heat into the case area. Now you need to improve case airflow, then you should have this puppy licked.
Now that they are getting close together (temps), improving case flow should bring them both down together.

Thanks for the ideas about modding those supports. I had my own idea about mounting a fan on the window. Remove the motor supports, but copy new ones into the plexiglass. Then just glue the fan's back plate to the center, with a pvc or aluminum shroud also glued onto the plexi. The fan would look like it's floating, and I could shape them like the panaflo's supports too.

Just my thoughts...Glad your succeeding! Ciao

[Godfodda]

Originally posted by Diggrr
Hey Godfadda,
You don't have a duct to the hsf fan? In that case it's perfectly sensible that the cpu would go down with the improved fan, and the case temp would go up. It's removing more cpu heat into the case area. Now you need to improve case airflow, then you should have this puppy licked.
Now that they are getting close together (temps), improving case flow should bring them both down together.

Thanks for the ideas about modding those supports. I had my own idea about mounting a fan on the window. Remove the motor supports, but copy new ones into the plexiglass. Then just glue the fan's back plate to the center, with a pvc or aluminum shroud also glued onto the plexi. The fan would look like it's floating, and I could shape them like the panaflo's supports too.

Just my thoughts...Glad your succeeding! Ciao

I thought it was sensible, too. ;)

The "floating fan" sounds cool. I'd like to see pics of that when you get it done.

No duct to the CPU on mine. This is a hacked case I grabbed off ebay to hold a SETI rig, but I'm working on cooling so I can boost the speed. I have 8 more 80's coming in next week, so now I have something to do with them. :)