Paul,

With your new approach on potting the outside of the rotor housing this
might be the time to reconsider in housing butterfly valves again.   I
need one point cleared up though.

Is the downside of a butterfly valve just the reduced cross sectional of
the port tube or is it an issue of  turbulence at WOT?

If the former than just increase the port size where the butterfly area
resides.
For instance if you start the tube dia. at 50 mm ID and after the valve
neck it down to your preferred size 48.6 then velocity would increase,
your desired cross sectional area remains the same but more importantly
the valve could go right into the housing like Power Sport did it.

Doug in Japan

I think it is both as well as an aerodynamic issue.
The preferred size is limited by the support the apex seal gets
as it crosses the port. The bigger the better. That is one reason
I am disappointed with the narrow rotor Mazda 16B.

BTW The wide rotor Aixro would generate much more power with a larger
p-port and a longer p-port runner. A whole bunch more power but the
charged cooled rotor temperature would be a negative issue.

Paul Lamar