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 ...
Front Door Key Cylinder Removal/Installation
1. Disconnect the negative battery cable..
2. Remove the service hole cover.
3. Detach the screw from the front door key cylinder.
NOTE:
The screw cannot be removed because the front outer handle bracket has a
stopper which prevents the screw from falling.
4. While pre ...
Flywheel Inspection [C66 M R]
1. Remove the flywheel..
2. Perform the following procedures to inspect the flywheel.
If there is any malfunction or it exceeds the maximum specification, replace
the flywheel..
a. Inspect the surface that contacts the clutch disc for scratches, nicks, and
discoloration.
...