Jerry Hey wrote:

Here is how version  3 of my exhaust system turned out.   The
muffler
to rad clearance is 4.375 inches.  Plenty of room for a shield.

    Another feature are the bellows.  With them I  can wiggle the
muffler an inch any direction. Of course it will eventually be
secured
to the aircraft frame. I am just going to tack weld the bellows. In
the
event they burn out, they can be removed with  a little grinding.  I
thought about kerfing the collars and clamping the bellows in place.
Probably should have done that.

  Another feature is the tube within a tube concept at the  flange.
This
was done by welding a stub to the inside of the flange.  This sticks
about about an inch.  The outer pipe which is expanded to fit
loosely
over the stub is welded to the outside of the flange.   BTW I like
the
heavy stock exhaust flange as opposed to the light weight Hatch type
flange.  The heavy flanges can absorb a lot of heat without getting
that hot. They should help control the temps in the first inch of
exhaust pipe where PowerSport's burned off.

This is intended to be a free flowing system. As far as noise is
concerned  I am hoping that the exhaust pulse will become
disorganized
when  it dumps into the pre-muffler and then tumbles out the square
muffler.   If it is too loud, I am prepared to add turbulators in
the
downward sloping portion of the muffler.  The exhaust pipes are
"tuned"
at 16 inches (32/2) in length. To get the length I had to extend the
pipes into the pre-muffler about an inch or so.

The entire system is made out of 304 SS.  The exhaust pipes are .065
and the muffler is .070.  The curved face on the  pre-muffler was
made
heat and a hammer.    Jerry

Jerry,

  Where did you get the exhaust bellows? I take it that it is also
304 SS?
Any guesses as to how well it will stand up to the heat? Might be a
solution for me but I'd need it in 2.5" size to go in after the
collector
on my header.

Mike Wills

Mike, the flexible exhaust bellows is made of quite thin 304 SS and it
may burn out in a minute or two.  I don't think it will however because
it is in a straight run of pipe.  The outside of bends is the danger
area.  At least  that is the theory I am operating with. Tomorrow I
will test a piece of. 020 304 in my forge and then we will know more
about what to expect.   Don't know why I did not think of it before.
Everything else about the bellows is perfect.  It provides capacity for
large relative movement between components.      I bought it after an
internet search from www.seniorautomotive.com.   Jerry

 
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