HP shutting down with boost increase.

[AndyF]

It was an interesting problem to solve. I never thought of the inlet collapsing when you first posted the issue. It sounded like an ignition problem, but someone noticed the boost going negative on the datalog and that was the clue. Proves the value of the datalogs.

[jdefina]

Yes, it was an interesting problem with so many possible causes.
In one of the tests I decided to keep my foot in it after the failure.
That's what showed negative manifold pressure at Wide Open Throttle.
Didn't make any sense, but the 8.9 A/F Ratio kind of confirmed this.
Pulling the input tract and removing the blower proved it wasn't
ignition related, even though lack of boost made ignition easier.
Hope this post will make life a little easier for somebody in the future
with a similar problem.