Air Intake System

Air is supplied to the supercharger via an intake cleaner/duct, throttle assembly and intake elbow which are similar to those used for normally aspirated engines. The supercharger delivers pressurized air to two separate charge air cooler units, each unit being mounted on the cylinder bank which it supplies. Pressurized cooled air is fed from the charge air coolers directly into each inlet port.

Air Intake Assembly





The air cleaner assembly consists of a two piece box containing the air filter, an airflow/temperature unit (MAP sensor) and the air intake duct, which connects to the top of the throttle assembly. The engine full load breather feeds into the intake duct from the bank 1 camshaft cover. Two tuned stubs on the air intake duct reduce the intake noise level.

Temperature Sensor





A second intake air temperature sensor (IAT sensor 2) is fitted at the outlet of the bank 1 charge air cooler. The sensor provides an input to the ECM.

Intake Elbow and Bypass





The intake elbow directs the metered airflow from the electronic throttle outlet (underside of the throttle body) into the intake of the supercharger.
The supercharger by-pass valve assembly is bolted to the intake elbow. The butterfly valve inside the assembly is opened by a diaphragm actuator operated by vacuum feed from the elbow. At closed or partially open throttle positions, the butterfly valve opens, allowing the airflow from the two charge air cooler inlets to be directed back to the supercharger inlet. This action inhibits the supercharging effect and reduces engine torque to non supercharged levels. Progressive opening of the throttle causes the by-pass valve to gradually close.
On the right-hand side of the elbow a large diameter pipe connects to the brake servo. On the left-hand side the smaller pipe supplies vacuum control for the evaporative emissions system valves.
Emissions from the engine part load breather (bank 1) and purged fuel vapor from the EVAP valve are drawn via a common T piece into the left-hand side of the intake elbow. Re-circulated exhaust gas enters the intake elbow via the EGR valve, which is mounted directly on the rear of the elbow. Where the EGR system is not used, a blanking plate is fitted.
The fuel system and emission control systems are described more fully in the relevant sections.

Fuel Pressure Regulation and Cruise Control Vacuum Feed
The inlet vacuum feed for the fuel rail pressure regulator and the cruise control system is taken from the supercharger outlet duct. The feed pipe is located below the large charge air cooler coolant filler plug.








Supercharger and associated components

Supercharger
The supercharger:
is attached to the three mounting bosses between the V of the cylinder block
has a filled for life internal lubrication system
is positively aligned with the drive belt by a doweled mounting bracket.

Charge Air Cooler System
Each cylinder bank is fitted with a charge air cooler unit, which supplies pressurized air to the four cylinders via an adapter block. The inlet ports to the two charge air coolers are connected to the supercharger outlet by an inlet assembly consisting of rubber ducts and clamp plates. An outlet stub at the rear of each charge air cooler unit provides the connection for the by-pass valve airflow. The charge air coolers are water cooled via a radiator and coolant pump.

Charge Air Cooler Coolant System





Each charge air cooler unit is a fin and tube air to liquid heat exchanger. The coolant circuit for the charge air coolers consists of a pump, radiator, connecting hoses and a bleed pipe.