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/InstallationFront Seat Back Trim Removal/Installation
WARNING:
Handling a side air bag improperly can accidentally operate (deploy) the
air bag, which may seriously injure you. Read the service warnings/cautions
in the Workshop Manual before handling the front seat (side air bag integrated)..
If the sliding mechanisms on both ...
Manifold Absolute Pressure (Map) Sensor
Purpose/Function
Detects the intake air pressure introduced into the cylinder as basic information
for mainly determining the fuel injection amount.
Detects the intake air pressure introduced into the cylinder and inputs it
to the PCM as an intake air pressure signal.
Cons ...
Driver and Front Passenger Occupant Classification System
First, please read “Supplemental Restraint System (SRS) Precautions” carefully.
Driver Seat Slide Position Sensor
Your vehicle is equipped with a driver seat slide position sensor as a part of
the supplemental restraint system. The sensor is located under the driver seat.
The sensor ...