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 Over Fender Removal/Installation
1. Remove fastener A.
2. Pull the front over fender lower in the direction of the arrow (1) while removing
hook B and pin C.
3. Remove fasteners D.
4. Pull the front over fender upper in the direction of the arrow (2) while removing
clips E.
5. Install in the reverse order of ...
Intake Air Temperature (Iat) Sensor Inspection
IAT Sensor No.1
Resistance inspection
NOTE:
Because the IAT sensor No.1 is integrated in the MAF sensor, replacing the
IAT sensor No.1 includes replacement of the MAF sensor/IAT sensor No.1.
1. Disconnect the negative battery cable..
2. Disconnect the MAF sensor/IAT sensor No.1 ...
Oil Pump [Skyactiv G 2.0]
Outline
The oil pump has a mechanism for feedback control of oil pressure. As a result,
an oil pressure increase of more than the set pressure is suppressed and oil
pump drive resistance is reduced. In addition, because the set pressure can
be changed (oil pressure two-step control) ...