Manifold and Turbocharger Section

The manifold incorporates the turbocharger turbine intake shut-off valve which is connected by a rod to the pressure actuator which is mounted on the turbocharger. The turbocharger turbine is also located within the manifold fabrication. The turbocharger housing is attached to the manifold with a two-piece clamp which is secured with a bolt and nut.

The turbocharger compressor is located within the turbocharger housing. Pressure pipes are connected to the inlet air side of the turbocharger housing and are connected to a turbine intake shut-off solenoid valve. When the solenoid is energized by a PWM (pulse width modulation) signal from the ECM (engine control module), the valve opens and pressure is used to operate the turbine intake shutoff valve vacuum actuator.

The turbine intake shut-off valve will start to open at about 0.35 bar (5.07 lbf/in² ), and will be fully open at about 0.55 bar (8.00 lbf/in² ) applied pressure at the actuator. The opening is controlled by the ECM, and may be modulated away from these values to provide optimum performance. The pressure to the actuator is modulated through the turbine intake shut-off solenoid valve, mounted on the bracket on the compressor housing.

On a quick throttle closing, the compressor can be running at high speed with no air flow, which is an unstable operating condition. This creates to a sound, or surge, which is quite noticeable in vehicle. To counteract this, the turbocharger is fitted with a vacuum actuated recirculation valve. The valve is connected via a tube to the intake manifold. The valve addresses the sound by responding to intake manifold vacuum (created when the throttle is closed). The vacuum activates the valve in the turbocharger which opens up a channel from the compressor outlet back to the compressor inlet. This recirculation of compressor air minimizes the unstable surge condition and the related noise.