12.7 under extreme boost 28-30lbs I hear teapot sound. Air Dryer?.

The compressor intake air line from the Manifold often fails at the compressor. Often it’s connected on the side, in a tight spot, between the compressor and block. It gets hot and fails. Hard to target the noise, especially if it’s just a small hole. Once it blows out more, you lose boost and power.

 

April of last year mine developed a loss of power on hard pulls. I looked and looked but couldn’t see the problem. Finally my high powered flashlight and my reading glasses helped me find a very small hole in one. It was the original hose 9 years plus and it showed signs of heat exposure.

 

Pressure test the CAC and hoses. Check the hoses under the rings, check the turbo boost outlet elbow clamp, look under the intake for a blown intake manifold gasket, the compressor supply hose, etc. Or just keep throwing parts.

What you think you're hearing is not what you're actually hearing is my bet.