Chevrolet Performance LT5 Instructions De Montage page 4

Fuel System
Low Pressure (Fuel Tank to Engine)
The production system uses a returnless variable flow/pressure system that has been incorporated in the Chevrolet Performance
engine control kit. A returnless fuel system reduces the internal temperature of the fuel tank by controlling the speed of the fuel
pump and not returning hot fuel from the engine to the fuel tank. If using the Chevrolet Performance engine control kit, a pulse
width modulation capable fuel pump that delivers 500 kPa (72psi) at 45 gallons per hour is required. If not using the Chevrolet
Performance engine control system, then a fuel pump and a regulator that delivers 500kPa (72psi) with 45 gallons per hour of flow
must be used.
High Pressure (On Engine)
The LT5 engine is equipped with two sets of fuel injectors. The (8) DI/primary fuel system consists of 8 separate direct injection
fuel injectors, two high pressure fuel rails, a high pressure cross-over fuel pipe (connects the two fuel rails), a high pressure fuel
feed pipe (connects the cross-over pipe to the high pressure fuel pump), a high pressure fuel pump and a low pressure fuel feed
pipe. The injectors are each seated into their individual bores in the cylinder heads with two combustion seals to provide sealing.
The high pressure fuel pump mounts to the rear of the Engine Block Valley Cover in the engine valley. Motion is transmitted to the
pump from a tri-lobe on the rear of the camshaft through a hydraulic roller lifter.
A second set of (8) PFI/secondary fuel injectors are mounted to the Supercharger assembly. The PFI/secondary fuel injectors are
present to supplement fuel delivered to the engine when the DI/primary fuel system is not capable of providing the total engine
fueling demand. The PFI/secondary fuel injectors are only activated at high engine loads when substantial fuel enrichment is
necessary for exhaust system protection or to achieve peak engine torque/power.
The high fuel pressure necessary for direct injection is supplied by the high pressure fuel pump. The high pressure fuel pump is
mounted on the rear of the engine under the intake supercharger manifold and is driven by a three-lobe cam on the camshaft. This
high pressure fuel pump also regulates the fuel pressure using an actuator in the form of an internal solenoid-controlled valve that
is controlled by the ECM.
Crankcase Ventilation System Description (LT5)
A positive crankcase ventilation (PCV) system is used in order to provide a more complete scavenging of crankcase vapors.
Filtered air from the air induction system duct is supplied to the crankcase, mixed with blow-by vapors, and passes through
a crankcase ventilation metering device before entering the supercharger. The primary component in the positive crankcase
ventilation (PCV) system is the PCV flow metering device (valve or orifice). Vacuum changes within the supercharger result in flow
variations of the blow-by vapors. If abnormal operating conditions occur, the design of the PCV system permits excessive amounts
of blow-by vapors to back flow through the crankcase vent tube and into the engine induction system to be consumed during
normal combustion. This engine ventilation system design minimizes oil consumption and significantly reduces the potential for oil
ingestion during vehicle limit handling maneuvers. There are two clean air supply locations for PCV. One on the right side valve
cover and one on the left side valve cover. See Figure 1
The LT5 engine utilizes an integral positive crankcase ventilation system which is located in the Engine Block Valley Cover beneath
the Supercharger Assembly. The Engine Block Valley Cover contains composite oil separating baffles and PCV plumbing. Filtered
fresh air is routed from upstream of the throttle plate to the engine oil tank where it mixes with crankcase gasses and is passed to
both engine rocker arm covers. The rocker arm covers' design shields rocker arm oil spray, thereby reducing the potential for oil
being drawn back into the tank during backflow of the ventilation system. Blow-by vapors are routed from the Engine Block Valley
Cover through a fixed orifice 7.5 mm (0.295 in) within a steel PCV tube, then into the underside of the supercharger near the front
of the engine block valley cover.
LT5 Dry Sump Engine Installation
TITLE
ALL INFORMATION WITHIN ABOVE BORDER TO BE PRINTED EXACTLY AS SHOWN ON 8 1/2 x 11
WHITE 16 POUND BOND PAPER. PRINT ON BOTH SIDES, EXCLUDING TEMPLATES.
TO BE UNITIZED IN ACCORDANCE WITH GM SPECIFICATIONS.
19417106
IR 03OC18
PART NO.
DATE
03OC18 Initial Release - Rocko Parker
4
SHEET
REVISION
36
OF
AUTH
N/A