The Dual VANOS system found on BMW’s S54 engine is a high-performance variable valve timing system that provides continuously variable control of both the intake and exhaust camshafts. Unlike the lower-pressure VANOS system used on engines such as the M52TU and M54, the S54 uses a dedicated exhaust-cam-driven radial piston pump to generate approximately 100 bar (1,450 psi) of hydraulic pressure, allowing extremely fast and precise camshaft adjustments even at high engine speeds. The DME controls four solenoids, advance and retard for each camshaft, to direct pressurized oil to the VANOS pistons, which move helical-splined adjustment shafts to change camshaft timing. This allows the S54 to continuously optimize valve timing and overlap for strong low- and mid-range torque, high-RPM power, throttle response, idle quality, emissions, and overall engine efficiency, while providing the rapid camshaft control required by the S54’s 8,000 RPM operating range.
