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/InstallationFresh Air Duct
Purpose, Function
Conducts fresh air from outside the engine compartment.
Increases air density by taking fresh air, which is cooler than the engine
compartment, to enhance the charging efficiency, ensuring the combustion stability.
Construction
The fresh-air duct is i ...
Air 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.
...
Rear Brake (Disc) Inspection
Brake Judder Repair Hints
Description
1. Brake judder concern has the following 3 characteristics:
Steering wheel vibration
1. The steering wheel vibrates in the rotation direction. This characteristic
is most noticeable when applying brakes at a vehicle speed of 100—140 km/h {62.2—86.9
...