Paul,

Agreed.   I finally found a way to get the Rhino file attached to you.
Sorry it only took a week:)
I have just shown the outside of the spin muffler.  The inside has two
perforated baffles that allow sound waves to interact but keep the gas
spiraling towards the center outlet.   Gas takes the path of least
resistance of course. Recently I`ve come to the conclusion that instead
of injecting cool air through the middle pipe, that it is wiser to block
off the inlet, have many holes drilled (at an angle)  in the center pipe
within the chamber, and put a  valve downstream of the muffler before it
joins with the turbine exhaust pipe.  Standard off the shelf valves can
be used or a cable activated device of your chosing.

The concept is to smoothly introduce the exhaust gas from the engine with
as little restriction as possible.  Ditto on  by passing through the
central pipe.  The outer casing can be standard Inconel pipe of about 4
inches.  The two inner baffles hang on the inner pipe.  The component
sizes would be determined depending on whether the inner pipe performed
an additional measure to support a built in turbine wastegate, or a
became a complete bypass.


Doug in Japan.

Nothing was attached Doug? You and Michiwaw need to have a child so
he or she can be put in charge of computers :) I don't think Yutaro is
up to it.