ZS Variable Intake System (VIS)

A graph of the VIS opening strategy from http://forums.mg-rover.org.

The intake unit (opened up, do not try this at home!) showing the six power valves feeding the cylinders and actuation arm operated by one of the motors. (Picture courtesy of Roger Parker, MGOC)

The two motors, plus the balance valve operated by the other motor. (Picture courtesy of Roger Parker, MGOC)