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Old 08-29-2009, 09:34 AM   #3 (permalink)
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A properly designed expansion chamber wil do a job similar to a supercharger.
It MUST be designed for the specific engine/rpm/curve you are looking for.
The way they work is harmonics. The pressure wave exiting the ex port draws some of the intake charge into the pipe. At the right time it is reflected back into the cylinder. As the intake ports have closed, the cyl is charged with a higher than atmospheric volume.
There are a few books out there on proper design of expansion chambers from the 70s and 80s.
After that time everyone went from single to multi stage units which are beyond anyone without a fluid engineering degree and cant be easily home rolled.
On a single stage the math is simple, and some basic welding will get it done in a weekend.
While youre at it have the cyl ported by a pro.
Uhhh,,, I guess I should add that this will result in more efficient use of fuel to stay on-board........
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