Bmw Turbo Repairs
Bmw Turbo Repairs
Bmw Turbo Repairs
Bmw Turbo Repairs

BMW Turbo Actuator

In a modern day turbocharger the variable vanes control the amount of exhaust gas pressure spinning the turbine, earlier turbochargers operated with out the aid of variable vanes which meant the exhaust gas pressure needed to build enough to spin the turbine there for creating what is know as turbo lag. Variable vanes operate by allowing a small amount of exhaust gas through to spin the turbine when the engine is at idle, this means the turbine is spinning before the engine speed is increased by the throttle, once engine speed is increased the vanes open fully and spin the turbine at full speed there for eliminating turbo lag.

The first variable vane turbos had a vacuum operated actuator controlled via a electronic solenoid valve, once vacuum is applied to the actuator the variable vanes are pulled to the minimum vane position allowing a small amount of exhaust gas pressure through to spin up the turbine. The actuator is spring loaded so once vacuum is disengaged the actuator pushes the vanes to the fully open position, the electronic solenoid is controlled via the ECU which receives various signal from engine sensors to determine how it reacts. Electronic actuators operate in almost the same way, they are not spring loaded but sit off set from the turbo, they are connected to the variable vane lever on the turbo via a small rod.