Ford 2003 Mustang Workshop Manual page 2113

SECTION 303-12: Intake Air Distribution and Filtering 2003 Mustang Workshop Manual
DESCRIPTION AND OPERATION
Intake Air Distribution and Filtering —Supercharger,
Charge Air Cooler
The supercharger (SC) is a positive displacement pump. Its purpose is to supply an excess volume of
intake air to the engine by increasing air pressure and density in the intake manifold. The supercharger
is matched to the engine by its displacement and belt ratio, and can provide excess airflow at any
engine speed.
NOTE: The supercharger is repaired only as an assembly. Disassembly of the supercharger unit may
void the warranty.
NOTE: The supercharger is not a bolt-on option. It is part of an integrated engine system. Many
components of the supercharged engine are not interchangeable with similar parts from a non-
supercharged engine.
The supercharger contains two three-lobed rotors. The helical shape and specialized porting provide a
smooth discharge flow and low level of noise during operation. The rotors are supported by ball
bearings in front and needle bearings at the rear. The drive gears are pressed into place, therefore the
supercharger is installed new as a unit, and is not repairable.
The supercharger system is a blow-through type with the fuel injected directly into the intake ports. The
supercharger is belt driven off the crankshaft through an idler pulley. The throttle body controls the
amount of intake air to the supercharger through the intake plenum. Air from the supercharger is
routed through the charge air cooler (CAC), then to the intake manifold. The resulting denser air
charge in the combustion chamber provides for a higher power output of the engine over a non-
supercharged engine of the same displacement.
NOTE: It is not possible to increase manifold pressure or engine power output by altering the bypass
valve or the actuator.
At partial-throttle opening or when vacuum is present in the intake system, a vacuum-controlled
bypass valve reroutes some discharged air from the supercharger back through the intake plenum.
This prevents the supercharger from cavitating, causing reduced performance, increased
temperatures, and poor fuel economy.
The supercharger has a self-contained oiling system that does not require a fluid change for the life of
the vehicle. However, at every 30,000 mile interval, the supercharger fluid level should be checked.
The vehicle should be parked on a level surface, the engine cool, and not running. To check the oil,
remove the Allen head plug located at the front of the supercharger. The oil level should be at the
bottom of the fill plug threads when cold. If the fluid level is low, add Synthetic Supercharger Fluid
E9SZ-19577-A or equivalent meeting Ford specification ESE-M99C115–A
Supercharged vehicles are equipped with a charge air cooler (CAC). The CAC cools the pressurized
air from the supercharger, increasing the air density, which improves combustion efficiency, engine
horsepower and torque.