My K40 is now 5 weeks old and has finally found a home in my basement! (Although I can’t quite understand why my wife didn’t like it on the coffee table next to the fireplace, to keep the peace I had to find a different place to vent it ). I know that the stock exhaust fan and connection leave a bit to be desired, but I wasn’t quite ready to throw in the towel and buy a new blower just yet.
Using some 4" duct piping, and some wood, I made some manifolds and a custom exhaust. I hacked the fan body as shown in the photos to try to maximize flow. I also took time to remove the flash off the plastic fan components to ensure smooth flow, especially around the inlet where the flash was really bad. I chose to use steel pipe rather than the flexible blue pipe to decrease resistance losses. I also tried to minimize the exhaust length and the number of elbows, again to minimize resistance losses and maximize air flow. (those fluid dynamics courses years ago finally pay off!)
I’m still going to tape up all the joints, but I’m pretty happy with the performance so far. Unfortunately I haven’t done any real world testing yet by actually cutting something. That will be next. Unfortunately, I have to go away on business for the next two weeks.