I like the open wastegate idea but the intake leak is probably a dead end (although it may give some good clues as to what is happening, maybe that's all you meant). 

 

I

 

Tracy, why do you think that the intake leak is a dead end?  I wouldn't thing a solution would be that simple, but OTOH I don't see any reason why it won't work if surge is really my problem.  At least as a temporizing measure until I can build-up and install the ported engine.

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Dave Leonard
Turbo Rotary RV-6 N4VY

Just a gut reaction based on turbo stuff absorbed in reading over the years (and zero experience).  To summarize:

 

Every inch of boost is a hard fought battle won by carefully matching intake manifold, exhaust turbine, turbine housing, compressor turbine & housing, engine operating point, etc, etc.  Dumping that pressurized air overboard to match things up is the equivalent to sending your fuel pressure regulator return to an outside vent.  It will work but the efficiency factor sucks. 

 

It could be argued that the exhaust energy was free anyway so it doesn’t matter.  I don't have enough real world data to back it up but I don't think this is true.

 

Took a look at the pictures you sent and I do see what you mean about your intake manifold  - wow.  You were right. 

 

Tracy