Exhaust System

MANIFOLD AND EXHAUST SYSTEM - K SERIES KV6

DESCRIPTION AND OPERATION

30-3-5

Description

Inlet Manifolds
The inlet manifold on the KV6 engine is located on the top of the engine, between the cylinder banks. The manifolds 
direct intake air into the cylinders where it is mixed with fuel delivered by the injectors prior to ignition in the cylinders. 
The inlet manifold comprises left and right hand cast aluminium inlet manifolds and a plastic moulded inlet manifold 
chamber.

Two handed aluminium inlet manifolds are secured to the cylinder heads using fourteen bolts and sealed with one 
piece composite gaskets. Three injectors, which are sealed with 'O' rings, are located in each manifold and are 
retained in position by the fuel rail. The fuel rails are secured to each manifold using two bolts. A coolant outlet is 
located in the left hand end of each manifold and a vacuum take-off point is located on the left hand manifold. Three 
'O' rings and three moulded seals provide the seal between the inlet manifolds and the inlet manifold chamber.

Inlet Manifold Chamber
The inlet manifold chamber is a one piece plastic moulding which is fitted on the inlet manifolds and secured with four 
bolts. Three 'O' rings and three moulded seals locate in recesses and seal between the inlet manifold chamber and 
the inlet manifolds.

The inlet manifold chamber features a single throttle body which feeds into a 'Y' piece, which separates into two 
secondary pipes. The secondary pipes connect to two main plenums, one for each bank of cylinders. At the closed 
end of the plenums is a balance valve which is operated by an electric motor. This valve enables the two plenums to 
be connected together.

From the two plenums, the primary tract length to the cylinder head face is approximately 500 mm. Each of these 
tracts has a side junction with a power valve leading to a short inlet tract plenum, approximately 350 mm from the 
cylinder head. Each power valve is connected to a link rod which is operated by a single electric motor.

Exhaust System
The manifolds and exhaust system is of welded steel construction and consists of five main parts;

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A RH (rear) manifold.

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A LH (front) manifold and catalytic converter.

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A RH downpipe and catalytic converter.

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A LH downpipe.

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An intermediate pipe.

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A tail silencer.

Close coupled catalytic converters are incorporated into the system to achieve fast converter light-off times after 
starting the engine. Heated Oxygen Sensors (HO2S) are installed upstream and downstream of each catalytic 
converter, to enable the ECM to exercise closed loop control of the air:fuel ratio and to monitor catalytic converter 
performance.

To reduce heat loss, the exhaust manifolds, the pipes between the exhaust manifolds and the catalytic converters, 
and the ends of the catalytic converters, are double walled with an air gap between the walls.

The system is suspended from the underside of the vehicle on mounting rubbers and a bracket on the downpipe and 
rear catalytic converter.