M52TU B25 And B28 Engines: VANOS

The double VANOS system is used on the M52 TU engine. Double VANOS was originally introduced on the European M3 engine, however, the system for the M52 TU engine is designed specifically for series production engines.

The single VANOS system of the M52 engine is a simple ON/OFF system. With the double VANOS system, true variable timing for both the intake and exhaust camshafts is possible.

In addition to offering increased power, the double VANOS system offers the following advantages:

• Increase torque in the lower and medium RPM ranges - without a loss of power in the upper RPM ranges
• Less un-burned gas when idling due to less camshaft overlap
• Improved idling characteristics due to less overlap
• Internal exhaust gas recirculation in the part load range for lower NOx emissions
• Quicker warm up cycle for the catalytic converter for faster reduction in emissions
• Improved fuel economy