Paul,

 I hope you don't think I'm nuts, but what would you think of essentially
 using your muffler as a manifold for mounting a turbocharger?  The
 turbocharger would be used mostly for normalizing  for altitude and the
 reduced heat and energy out of the muffler would prolong the life of the
 turbocharger.  The muffler must also be fairly stout to survive being
 mounted directly to the exhaust ports it should minimize the weight for
 the
 whole installation.  I think it would also be more compact than using a
 manifold and turbocharger with a muffler downstream.

 Steve Brazil

 It will work. What you wind up with is a slightly less efficient
 aerodynamic systems so you lose a bit of velocity on the turbine.
 The same goes for the intake side. If you want the best BSFC
 on a turbo engine use p-ports.

 Paul Lamar


 Another thought..  A turbocompound engine should be very quiet without
 a muffler.  Turbines in series.  Except when wastegate(s) is(/are)
 open.

 Matt-


 Matt,

 I agree that the turbo-compound would be the best, but I'm looking at
 hardware that is available or at least not prohibitive for me to develop.  I
 can build the muffler.  The goal is an affordable helicopter engine with
 turbine-like performance and reliability.  I can live with a little less
 efficiency if the turbine lives longer and the package is lighter and more
 compact.

 Steve



Steve,


  I have been thinking along these lines as well.  The only
issue I found is under the cowl clearance.  It other words
the addition of the  six inch 'log' the manifold to it and
then the seven inch width of the turbocharger adds a significant
amount of  width to your engine installation.  Compare that
to the auto engine package which is extremely tight and
only adds about seven inches to  the engine width.


Doug in Japan