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/InstallationExpansion Valve Removal/Installation
1. Disconnect the negative battery cable..
2. Discharge the refrigerant from the system..
CAUTION:
If moisture or foreign material enters the refrigeration cycle, cooling ability
will be lowered and abnormal noise will occur. Always immediately plug all open
fittings after removing ...
Rear Differential Removal/Installation
WARNING:
When replacing the coupling component, read the special character string
before installing a new coupling component and write it to the AWD control module
after replacement. The special character string is indicated in the two locations
shown in the figure.
1. D ...
Center Accessory Socket Removal/Installation
1. Disconnect the negative battery cable..
2. Remove the upper console..
3. Insert a tape-wrapped flathead screwdriver into the gap between the cap tab
and socket.
4. Move the flathead screwdriver in the direction of the arrow (1) shown in the
figure, press the center accessory socket ...