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/InstallationHeadliner Removal/Installation
1. Disconnect the negative battery cable..
2. Remove the following parts:
a. Sunroof seaming welt (with sunroof system).
b. A-pillar trim.
c. Front map light.
d. Sunvisor.
e. Front scuff plate.
f. Rear scuff plate.
g. B-pillar lower trim.
h. Adjust anchor cover.
i. Upper anchor i ...
Rear Spoiler Removal/Installation
Removal
WARNING:
Using a utility knife with bare hands can cause injury. Always wear gloves
when using a utility knife.
1. Remove the liftgate upper trim.
2. Remove caps A.
3. Remove nuts B.
4. Attach a piece of wire between the liftgate striker and liftgate latch to
ho ...
Rear Heat Duct Removal/Installation
1. Disconnect the negative battery cable..
2. Remove the following parts:
a. Decoration panel.
b. Shift lever knob (MTX).
c. Front console box.
d. Shift panel.
e. Upper panel.
f. Rear console.
g. Side wall.
h. Front console.
i. Front scuff plate.
j. Front side trim.
k. Joint ...