Audi 2003 A8 Technical Features page 26

Engine, Mechanics
V8 5V 3.7 l/4.2 l engine
The 3.7 l and 4.2 l V8 engines were adopted
from the predecessor model with certain
modifications.
These modifications relate to the intake and
exhaust systems and are described in the
following.
Variable-intake manifold in 4.2 l engine
This takes the form of a 2-stage variable-intake
manifold made of a die-cast magnesium alloy,
bonded and bolted together in four sections.
The two-stage design permits the use of two
intake paths with large cross section.
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Design and operation are described in
SSP 217.
The intake manifold must be replaced as
a complete unit when performing
repairs.
SSP282_013