Ok just had another Harbor Freight blower take a dump I go through these things once every 1.5 - 2 years plus fight the neighbors on noise.
The set up 4" line through the wall to blower then 4" pipe straight up 15 feet. I have a box around the two motors but still lots of noise. I also would like to get more suction.

So any ideas?
Different motor / exhaust units / piping I need to do 2 of these eventually.
Thanks