On our PA 24-250 we have twin Rajay Turbos, after market with manual operation. Usually I am pretty savvy with this stuff but have a problem I can't seem to identify.
I tend to fly 9 to 12000ft and in my part of the world, the Eastern side of the continent with North South trips, I usually only use the Turbos to climb keeping 25/25 to altitude and then pull them off.
My problem is that as I add the boost, initially it works and keeps 25/25 but then suddenly all boost is lost. I had problem years ago with the hinges on the flapper plate in the air box breaking, that is the plate that closes closes the normal air inlet and directs the Turbo air into the system. That problem caused the complete loss of boost. The hing and hinge pin were replaced and its worked ever since, until now. I now check this hinge and pin every annual. Also all air hoses are without leaks, and Turbo Oil pressure light goes out indicating adequate pressure.

The only thing I can think of is that the flapper plate is initially closing, directing the Turbo air correctly and then suddenly falling back, but I am lost as to why. Looking for suggestions or if anyone has experienced such a thing, and what was the fix.

Chris Elgar
Burlington, Canada.

Chris,
Check the wastegates. If it is not closing all the way, as soon as the ram air pressure has enough force to open the flapper door, all boost will be lost.
-Zach