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/InstallationSide Sill Panel Removal [Panel Replacement]
Symbol Mark
Removal Procedure
Side sill (front side)
1. Rough cut the 2 locations indicated by (A) shown in the figure.
2. Drill the 18 locations indicated by (B) shown in the figure.
3. Remove the cabin side outer frame (outer side sill).
Side sill (component)
1. Rough cut the 3 l ...
Igniter Removal/Installation
WARNING:
Incorrect servicing of the discharge headlights could result in electrical
shock. Before servicing the discharge headlights, always refer to the service
warnings..
Igniter (LH)
1. Disconnect the negative battery cable..
2. Remove the air cleaner cover..
3. Remove th ...
Battery Inspection [Skyactiv G 2.0]
WARNING:
Since battery acid is toxic, be careful when handling the battery.
Since battery acid is highly corrosive, be careful not to allow it to contact
clothing or the vehicle.
In case battery acid contacts skin, eyes, or clothing, flush it immediately
with running wa ...