Active valve control system

The ECU is programmed to operate control valves that adjust the delivery of the hydraulic pressure in order to move the camshaft into the position that will provide the engine with the best performance while meeting emissions standards.

A dual AVCS system phases both the intake and exhaust camshafts on the EZ36 found in the 2008+ Tribeca, 2009+ Outback 3.6R, 2009+ Legacy 3.6R, and on the 2008+ STi EJ257 (W25 heads).

In AVCS, the engine computer (ECU) can command a solenoid which advances or retards the camshaft rotation by up to 35 degrees.

At very high engine loads, AVCS advances the intake valves further to open even sooner during the exhaust stroke.

This results in improved volumetric efficiency, increased dynamic compression, and helps to generate higher power output.