Spent some time on the boost controller project today. First tried to find a spring that would allow the check valve to open at maybe 8-9 pounds but no luck. So I just removed the check valve allowing the system to function like the Vibrant with only the needle valve to provide bleed.
It works pretty well. I've currently got the controller set to provide a maximum boost pressure of 12.3 pounds. This is a bit under the 12.8 or so maximum for stock so I've got a bit of a cushion for now. I'll continue to monitor things for awhile and maybe open it up just a bit more provided EGTs don't get out of line or the pressure creep up. No smoke to speak of either.
So for the time being I'm happy with the much improved performance the additional boost provides.
Not sure I like the yellow silicone tubing, but anyway here's my installation -
By the way, the fittings on the Tee are way too small for the tubing, so I used a small length of silicone tubing as a shim. With the clamps it's quite secure.