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/InstallationTorque Converter [Fw6 A EL, Fw6 Ax EL]
Purpose/Function
By use of an optimized torus shape (wing) matching the output characteristics
of the engine, the torque converter achieves efficient force transmission and
reduced fuel consumption.
Construction/Operation
A three-member, single-stage two-phase type torque c ...
Climate Control Unit Removal/Installation [Full Auto Air Conditioner]
NOTE:
The climate control unit prior to replacement stores the vehicle specification
information.
The new climate control unit does not store any vehicle specification information.
When the ignition is switched ON after the climate control unit is replaced,
the climate ...
Rear Drive Shaft Removal/Installation
CAUTION:
Performing the following procedures without first removing the ABS wheel?speed
sensor may possibly cause an open circuit in the harness if it is pulled by
mistake. Before performing the following procedures, remove the ABS wheel?speed
sensor (wheel side) and fix it to an ...