Intake Air Distribution and Filtering

Intake Air Distribution and Filtering

COMPONENT LOCATION









INTRODUCTION
The intake air distribution and filtering system comprises:
- Dual air intakes, air cleaners and air ducts.
- A supercharger and intake manifolds.
- A noise feedback system.

AIR INTAKES, AIR CLEANERS AND AIR DUCTS









The air intakes supply air from behind the front bumper to the air cleaners. A grommet and bracket attaches each air intake to the related side air deflector of the radiator. Quarter wave tubes are installed on the air intakes to reduce air induction noise. The RH (right-hand) air intake incorporates a bracket for the pollution sensor.
The air cleaners are located forward of the front wheels, behind the fender splash shields. Two mounting points, both consisting of a grommet installed on a bracket, attach each of the air cleaners to the fender extension of the related front side member and to a bracket on the front bumper beam. Each air cleaner consists of a casing with inlet and outlet connections. A removable cassette drawer holds a tray and a replaceable air cleaner element. Two screws secure the cassette drawer in the closed position in the casing. The underside of the casing incorporates a drain valve to prevent the accumulation of water in the air cleaner. The outlet connection of each air cleaner incorporates a MAFT (mass air flow and temperature) sensor.

Air Cleaner









The air ducts direct the air from the air cleaners to the electric throttle. The air ducts consist of LH (left-hand) and RH (right-hand) outlet ducts, LH (left-hand) and RH (right-hand) engine intake ducts and a throttle T-piece duct. Hose clamps connect the ducts together and to the air cleaners and the electric throttle.
The air ducts incorporate the following mounting points, which all consist of a grommet installed on a bracket:
- One on each outlet duct, attached to the related front side member.
- One on each engine intake duct, attached to brackets on the front cross member.
- One on the throttle T-piece duct, attached to a bracket on the RH (right-hand) cylinder head.
The air ducts also incorporate the following:
- On the outlet ducts, quarter wave tubes to reduce air induction noise.
- On the LH (left-hand) engine intake duct, a resonator, to reduce air induction noise, and a connector stub for the engine full load breather pipe.
- On the throttle T-piece, a resonator, to reduce air induction noise, and a connector stub for the vacuum tube of the bypass valve actuator on the supercharger.

SUPERCHARGER AND INTAKE MANIFOLDS
The SC (supercharger) increases the pressure, and thus mass, of the air supplied to the engine, to increase the engine's power output. Two separate intake manifolds direct air from the SC (supercharger) to the cylinder inlet ports.
The intake manifolds are attached to their related cylinder heads and the sides of the SC (supercharger). Two dowels locate the SC (supercharger) in position on the cylinder block. A charge air cooler tank top is installed on top of the SC (supercharger) and intake manifolds to form the air duct from the SC (supercharger) outlet to the intake manifolds. A charge air cooler is installed in each intake manifold.
The charge air cooler tank top incorporates four studs for the attachment of the engine cover. A NVH (noise, vibration and harshness) pad is attached to the side of each intake manifold.

Supercharger and Intake Manifolds - Assembled









Supercharger and Intake Manifolds - Exploded









Supercharger
The SC (supercharger) is a Roots blower with high angle helix rotors driven at 2.1 x engine speed by the secondary belt of the accessory drive.
The two rotors of the SC (supercharger) are contained in a housing. The ends of the rotors are supported in bearings in the front cover and the bearing plate. A rear cover seals the bearing plate and incorporates a filler/level plug for lubricant. A pulley transfers power from the accessory drive to the shaft of one of the rotors.
A pneumatic actuator on the front cover is attached to a by-pass valve in the housing. The bypass valve regulates a flow of air from the outlet of the SC (supercharger) back to the inlet side of the rotors, to control the outlet pressure of the SC (supercharger). Hoses connect the pneumatic actuator to the throttle T-piece of the air ducts, upstream of the electric throttle, and to the front cover, downstream of the electric throttle. A lever connects the actuating rod of the pneumatic actuator to the shaft of the bypass valve. A screw in the front cover limits movement of the lever in the closed direction to allow calibration of the SC (supercharger) output.
The front cover also incorporates:
- The SC (supercharger) air inlet and mounting face for the electric throttle.
- A connector stub for the part load breather.
- A MAP (manifold absolute pressure) sensor.
- A connector stub for a hose from the EVAP (evaporative emission) canister purge valve.

Intake Manifolds
Each intake manifold is attached to the SC (supercharger) with three screws and a bolt. Two dowels ensure correct alignment of each intake manifold. The RHD (right-hand drive) intake manifold incorporates a connection port for the noise feedback system. The LH (left-hand) intake manifold incorporates:
- A connector stub for the brake vacuum system.
- A MAPT (manifold absolute pressure and temperature) sensor.

NOISE FEEDBACK SYSTEM









The noise feedback system generates a sporty, powerful engine sound in the passenger compartment, at high engine load and speed settings, to enhance the driving experience. The noise feedback system consists of a symposer system, a feedback tube and a resonator. Activation of the noise feedback system is controlled by the ECM (engine control module).

Symposer System
The symposer system modifies induction sound waves of a specific frequency range, at given engine settings, to produce the required engine sound. The symposer system consists of:
- An inlet pipe and flange.
- A symposer and pneumatic valve assembly.
- A tuning valve and associated vacuum tubes.
- An outlet pipe.
- An outlet adapter.
The inlet pipe and flange transfer induction noise from the RH (right-hand) intake manifold to the symposer. The pipe is a push fit on the symposer and the flange, which is attached to the rear face of the RH (right-hand) intake manifold.
The symposer contains two pairs of chambers, one pair on the inlet side and one pair on the outlet side. The inlet pipe connects to one of the chambers on the inlet side of the symposer, and the pneumatic valve connects to one of the chambers on the outlet side of the symposer. A calibrated orifice in the inlet pipe connection on the symposer limits the range of sound waves that pass through it. A 'paddle' installed in a diaphragm forms the separating wall in each pair of chambers. The paddle is able to pivot about its lateral axis where it passes through the wall that separates the two pairs of chambers.

Symposer









The pneumatic valve controls the flow of sound from the symposer outlet. It is a normally-closed valve connected directly to the outlet of the symposer and operated by vacuum pressure. Two isolators, one on the pneumatic valve and one on the symposer, locate the assembly on a bracket attached to the SC (supercharger) rear cover.
The tuning valve controls the application of vacuum pressure to the pneumatic valve. Two screws attach the tuning valve to the same bracket as the symposer and pneumatic valve. The tuning valve is a normally-closed solenoid-operated valve installed in the vacuum line between a T-connection in the brake vacuum system and the pneumatic valve. A vent cap on the tuning valve allows atmospheric pressure into the vacuum line to the pneumatic valve when the tuning valve is closed.
The outlet pipe carries sound from the pneumatic valve to the feedback tube via the outlet adapter. The outlet pipe is a push fit on the pneumatic valve and in the outlet adapter. A screw attaches the outlet adapter to an engine harness bracket installed between the two intake manifolds.

Feedback Tube
The feedback tube transfers the sound from the symposer system to the resonator. Clips secure the feedback tube to the outlet adapter of the symposer system and to the resonator.

Resonator
The resonator directs the sound from the feedback tube into the passenger compartment. The resonator is installed in the passenger compartment side of the engine bulkhead, on two mounting grommets each consisting of an isolator and a compression limiter.

CONTROL DIAGRAM (NOISE FEEDBACK SYSTEM)

NOTE:
A = Hardwired









PRINCIPLES OF OPERATION

Supercharger
At closed or partially open throttle positions, the bypass valve is fully open, allowing a flow of air from the SC (supercharger) outlet back to the inlet side. This results in little or no pressure increase across the SC (supercharger). Progressive opening of the throttle reduces the depression downstream of the electric throttle. This is sensed by the pneumatic actuator, which moves to close the bypass valve. As the bypass valve closes there is a corresponding increase in the outlet pressure from the SC (supercharger), which increases engine power output.

Noise Feedback System
Sound waves from the RH (right-hand) intake manifold are filtered by the calibrated orifice in the inlet pipe connection on the symposer. The sound waves make the paddle oscillate and generate pulsations in the outlet chambers. When the pneumatic valve is open, the pulsations are transmitted through the outlet pipe and feedback tube to the resonator in the passenger compartment.
The tuning valve of the noise feedback system receives a power feed from the power distribution box and is connected to ground through the ECM (engine control module). At lower engine loads and speeds the ECM (engine control module) keeps the ground open circuit and the tuning valve is de-energized closed. Atmospheric pressure is sensed at the pneumatic valve through the vent cap on the tuning valve, which keeps the pneumatic valve closed and prevents sound from the symposer entering the feedback system.
At higher engine loads and speeds the ECM (engine control module) connects the tuning valve to ground. The tuning valve energizes, blanks off the atmospheric vent and opens the vacuum line between the brake vacuum system and the pneumatic valve. The depression in the brake vacuum system is sensed at the pneumatic valve, which opens and allows sound from the symposer into the feedback system.
The status of the pneumatic valve at various engine loads and speeds is given below:

NOTE:
Values are for valve opening with increasing engine load and speed. Deduct 0.05 g/rev and 50 rev/min for valve closing with decreasing engine load and speed.