Questions:  at any particular RPM is the exhaust temp constant and
predictable?  It seems like the exhaust pipe length would have to
vary with the mixture.  Tracy is operating his engine one or two
hundred degrees below peak and most of  us want to do likewise.  How
does this reality interface with the ideal exhaust pipe length?  If
you tune you engine for 6000 rpm, is it then out of tune at 5500 rpm
or 6500 rpm?   Does a pipe become gradually more in tune as it
approaches the ideal length or is it suddenly in or out of tune.
Example,  I was trying to attain 32inch pipe length but had to settle
for 28 inches.  Does this mean that to have a tuned engine all I
would have to do is operate it at a higher rpm where 28 inches was
the perfect length?        Should the engine be tuned for max
performance at 6000 rpm or should it be tuned for best cruise
performance?    And so on.......Jerry

True but it does not seem to be that critical. +/- 500 RPM
will not make that much of a difference.

Take your pick. If you tune for cruise you might be able
to reduce the fuel burn.

Paul Lamar

Tom Webber wrote:

This is all fascinating,  I'll through in my little bit of experience with a tuned system.  I used
to own a Kawasaki GPZ1100.  Bought it new, during the break in period I was to keep the RPM below
4500.  The bike performed well,  But no great shakes.  The 500 Mile mark was made and it was time
to let the ponies out.  Well let me tell you that engine started to breath at 6000 RPM and pulled
hard right up to 8500.  It was like it had a turbo in it, but it didn't.  What a blast.  Anyway,
I think if we get our exhaust systems close to the optimum we will be better off then not trying.
FWIW.. T.W.

 
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