Copyright by Goodheart-Willcox Co., Inc.
Chapter 16 Turbocharging and Supercharging Systems 345
9
5
3 7
10 6 4 8 1
2
A
B
Figure 16-28. Reinstalling a supercharger. A—Carefully clean
the mating surfaces and install a new gasket. Use sealant as
recommended. B—Torque the fasteners in the recommended
sequence.
1 7 5 9 4
3 10 6 8 2
Figure 16-29. When reinstalling an intercooler, torque the
fasteners in the recommended sequence.
Figure 16-27. Remove all of the bolts that secure the super-
charger to the engine.
to a radiator shop for pressure testing. A radiator shop can
also flush the intercooler to remove scale or deposits in the
cooling tubes.
When reinstalling the intercooler, carefully clean all
gasket surfaces. Apply sealer as recommended and fit the
new gaskets. Without hitting and damaging any of the fins,
carefully lower the intercooler into place. Torque the inter-
cooler fasteners to specifications in the specified pattern,
Figure 16-29.
Warning: Never open the intercooler
cooling system when it is under pressure.
The operating temperature of the intercooler
coolant is hot enough to cause severe burns. Remove
the intercooler radiator cap slowly to verify that the
system is not under pressure.
Summary
Normal aspiration means the engine uses only out-
side air pressure to cause airflow into the combustion
chambers. With only outside air pressure to carry oxygen
into the engine cylinders, engine power is limited by the
engine’s volumetric efficiency. Turbocharging and super-
charging pressurizes the incoming air. This has the effect
of increasing the volumetric efficiency.
Turbocharged and supercharged engines normally
have several modifications to make them withstand the
increased horsepower. A few of these modifications
include lower compression ratio; stronger rods, pistons,
crankshaft, and bearings; higher-volume oil pump; larger
radiator; O-ring–type head gasket; valves with increased
heat resistance; and an oil cooler.
The major parts of a turbocharger are the turbine
housing, turbine wheel, turbo shaft, compressor wheel,
compressor housing, bearing housing. During engine
operation, hot exhaust gasses spin the turbine wheel. The
compressor wheel, which is connected to the turbine
wheel by the turbo shaft, spins to compress the incoming
air in the intake manifold.
Turbo lag is a short delay period before the turbo
develops sufficient boost. Boost is any pressure above
atmospheric pressure in the intake manifold. Turbo lag is
caused by the compressor and turbine wheels not spinning
fast enough.
Adequate lubrication is needed to protect the turbo shaft
and bearings from damage. A turbocharger can operate at
speeds up to 100,000 rpm. For this reason, the engine lubri-
cation system forces engine oil into the turbo shaft bearings.