Purpose, Function
By lengthening the exhaust passage, the transmission of exhaust pressure waves to other cylinders can be delayed, and the amount of gas exhausted from a cylinder and forced back inside the combustion chamber is reduced By reducing the residual gas, the temperature inside the combustion chamber is reduced and the occurrence of knocking even at a high compression ratio is inhibited.
Construction
The exhaust manifold is installed to the rear of the engine. In addition, the catalytic converter (WU-TWC) is integrated (WU-TWC).

When the No.1 cylinder is at the intake stroke, the No.3 cylinder is at the exhaust stroke. By inducing the high temperature gas exhausted from the No.3 cylinder into the No.1 cylinder, the high temperature gas in the No.1 cylinder remains. If the amount of residual gas is high, the temperature in the combustion chamber rises and knocking can easily occur. With the 4-2-1 exhaust system, the transmission of exhaust pressure waves between each cylinder is delayed by the long exhaust pipes.

Exhaust System Removal/InstallationAdjuster Anchor Removal/Installation
WARNING:
The side air bag sensor is attached to the lower part of the B-pillar. When
working around the B-pillar, disconnect the negative battery cable or work carefully,
avoiding excessive impact to the lower part of the B-pillar (with side air bag
sensor No.1).
1. Switch the ...
Wheel Hub, Steering Knuckle Removal/Installation
CAUTION:
Performing the following procedures without first removing the ABS wheel-speed
sensor may possibly cause an open circuit in the wiring harness if it is pulled
by mistake. Before performing the following procedures, disconnect the ABS wheel-speed
sensor connector (axle sid ...
Oil Pressure Switch Inspection
1. Switch the ignition ON (engine off) and verify that the oil pressure warning
light is illuminated.
2. Start the engine and verify that the oil pressure warning light turns off.
If the oil pressure warning light is not illuminated or remains illuminated,
inspect the wiring harness ...