[moonmonkey]

i have seen a 2cyl engine with an active port size (valve), that was added to lend low end torque to the engine while still allowing top end power. and we know that exaust size works better/worse depending on rpm and other factors, would an active exaust size ("valve") that was controlled by engine rpm,load and other fators help? i almost never exceed 3300 rpm and the majority of the time stay between2500-2750 rpm, since my engine hits peak torque at a higher rpm, could it be retuned to be more efficent at a lower rpm ? im talking about exaust pipe size not the valve in the head.