And now for the finale...
It works. Really damn well.
These photos are after running it for 10 minutes straight at 100psi. It looks like I did increase the pump temperature by around 20 degrees because I'm sucking air through a warm cooler before running it across the compressor head.
(By the way, shop temps were around 55-60 degrees for BOTH tests. It wasn't a hot day here in the South at all.)
Temperatures dropped by 230+ degrees between the compressor head and the exit of the oil cooler, and then stayed fairly stable, with the tank holding less than 20 degrees above ambient during the full-blast test.
Lots of water in the mini-Franzinator, a bit in the tank. Dry air coming out of a hose plumbed directly into the side of the tank without any filters or separators (which I will be adding anyway, since I plan to paint with this setup!)
The unloader valve does hiss much longer / louder now that it has to depressurize the cooler and the water trap - it airs down for exactly 11 seconds after the pressure switch opens. But I really like having the separator / Franzinator Jr where it is - once the unloader pops off, I can simply drain the accumulated water without it blasting all over the floor. I'll be able to keep a small bucket underneath it and just twist the ball valve open every once in a while, as well as leaving it open to help keep the separator clean inside between uses of the compressor, without totally dumping the air out of the tank.
Now I can fix two small air leaks that I found during testing, and clean the pipe assembly up and shoot it with gloss black to match the tank.
Photo 1: Pump exit
Photo 2: Cooler in
Photo 3: Cooler exit
Photo 4: Tank temp