Worked like a charm. Not particularly quiet at 116 db 3 feet away
but that can be fixed. More later.

Paul Lamar

Here is Tracy with the base set up. 98 to 102 db 3 feet away.

I put my hand in front of the [new] muffler and little or no exhaust
gas was exiting. Even less at 5000 to 6000 RPM. This is the first
cut with the end of the center pipe adjacent to the start of
the three inch exit pipe. There is room there for optimization
but optimization is not really needed IMHO.

Of course I could not hold my hand behind it for ANY length of time :)
We were not able to get the 90 degree down pipe in there between the
end of the muffler and the firewall so we tested it without the
down pipe. I am sure it would have been quieter with the down pipe.

Paul Lamar

Al Gietzen wrote:

Very important to have the 90 degree downpipe in order to have a
meaningful result.  A bit of back pressure at the exit is what will
cause exhaust to exit at the front.

Al

Well perhaps Al. But the position of the exit of the inner pipe
will also affect the results. What we have here is just a first guess.
The inner pipe stops right at the start of the down pipe.

I suspect continuing the inner pipe further along inside the down pipe
will improve the excellent results we have so far.

I will be doing further testing as soon as the dyno is done.

Paul Lamar
 
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