I got an idea after seeing Ernest Rowe add a larger plenum to his Impact test gun via the regulator gauge hole. He says "larger lung = faster dart". So I was going to machine one like Mr Rowe had until I noticed something on my bench that would work as is. Anyone with a Yong Heng compressor will recognize it as the little inline filter housing. The threads are M10x1 which is extremely close to 1/8" BSP. I ordered an M10x1 to 1/8" BSP male male coupler from Ebay to mate to the rifle and added 3 turns of heavy duty aluminum foil around the threads of my OEM FX manometer and used a steel washer with oring to be sure it sealed. The fit was very good with no leaks at all. The end result was a good bit more velocity but terribly inconsistent. Unmodified velocity is 887. With the 45g JSP Some shots were 840 up to 915 and everything in between. I plan to install a larger valve seat from Mr Rowe and make a twin transfer port and probe. I've taken my toys apart and modified them since I was a little kid, it's what makes me tick. What do you think caused the extreme spread?
EDIT: I didn't notice at the time of trying this that the valve housing lower bridge blocks the rear gauge hole. So my test was useless. Ernest Rowe mills the lower bridge off for his power tune.
EDIT: I didn't notice at the time of trying this that the valve housing lower bridge blocks the rear gauge hole. So my test was useless. Ernest Rowe mills the lower bridge off for his power tune.