This is an experimental setup, so please excuse the un-finished look of it. It's been running successfully for a while, so I thought some of you may like to see it's progress so far.
As you can see in the pictures
, I moved the PSU to the bottom of the setup after removing the fan. There is a 120mm fan in the center of the lower case, blowing out through the PSU. This is the only fan in the whole computer, other than the stock Intel cpu fan.
The whole case is sealed at all other openings, so all the air blown out the psu opening has come through the filter at the top, across the board and cpu, down and over the hard drive, through a 4" hole under the hard drive, into the lower case and out through the PSU.
It works perfectly with both fans under-volted. With the cpu fan running about 3200 rpm, and the case fan running about 1500rpm, the setup is very quiet. I'm still working on a new muffler setup for the lower case....more to follow.