Post by protocol1 on Jun 30, 2021 18:04:23 GMT -5
Just to clarify, the expansion chamber used for a best fit from a different engine, is mostly associated with the exhaust port timing. That is, the opening and closing times in degrees crank angle, and exhaust port open duration in crank angle degrees. This is because the dimensions of the expansion chamber pipe are set up to time the reflected exhaust pulse wave to arrive back at the exhaust port in time to push fresh air/fuel charge that escaped out of the open exhaust port, back into the cylinder in order to enhance the filling of the cylinder with fresh air/fuel mixture during the scavanging period. Expansion chamber exhausts work over a limited RPM band, since the maximum effect provided is synchronous with the exhaust event for each cycle. The time for the reflected exhaust pulse wave arriving back at the open exhaust port is the controlling variable and varies with expansion chamber dimensions.