The Active Muffler Control (AMC) system is used across the Buell XB12 series. The AMC serves two purposes; to improve mid-range torque and to decrease noise.

Torque is managed by effectively changing the exhaust system pipe length. An electronically controlled actuator opens or closes a butterfly valve (via a cable) that controls exhaust flow through a multi-chamber muffler. The Engine Control Module (ECM) monitors engine speed and throttle position while alternating flow paths between the chambers to adjust effective tuned length and therefore backpressure, optimizing torque and horsepower for the riding condition:

1. At low RPM with a wide-open throttle (WOT), the valve is opened (SHORT Exhaust Pipe) so the engine can gain RPM quickly.

2. In the mid-range, the valve is closed (LONG Exhaust Pipe) to increase acceleration torque.

3. At high RPM, the valve opens (SHORT Exhaust Pipe) again to maximize horsepower.

Note the actuator operation relative to the tachometer readings as seen in the video. When the cable wheel is fully clockwise the AMC valve is closed (AMC OFF), fully counterclockwise is open (AMC ON).

Operational States:
AMC OFF (Muffler Valve CLOSED = LONG Exhaust Pipe)
AMC ON (Muffler valve OPEN = SHORT Exhaust Pipe)

Operation:
AMC OFF below 1450 RPM
AMC ON above 1500 RPM
AMC ON below 3300 RPM
AMC OFF above 3350 RPM
AMC OFF below 5050 RPM
AMC ON above 5100 RPM

Normally the AMC is only active under WOT conditions. In order to slow down the action to make this video I overrode that particular setting using an ECM programmer (ECMdroid and BuellTooth device).

свернуть