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/InstallationAir Intake Actuator [Full Auto Air Conditioner]
Purpose
The air intake actuator moves the air intake door in the blower unit to switch
the air intake port.
Function
The air intake actuator drives the motor based on the signal from the climate
control unit and moves the air intake door to the FRESH or REC position.
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Front Fog Light Aiming
NOTE:
Perform front fog light aiming if any of the following work is performed.
Front fog light replacement
Work that can affect vehicle height such as suspension replacement or
removal/installation.
1. Empty the vehicle by having all occupants leave ...
Fuel Pump Control Module
Purpose, Function
Controls the voltage applied to the fuel pump for reducing fuel pump load
and improving fuel economy.
Controls the voltage applied to the fuel pump based on the control signal
from the PCM.
Construction
The fuel pump control module is installed bel ...