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/InstallationRoof Carrier Bracket 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 ...
Floor Under Cover Removal/Installation
1. Lift up the vehicle.
2. Remove bolts A.
3. Remove fasteners B.
4. Remove the floor under cover No.1.
5. Remove nuts C.
6. Remove fasteners D.
7. Remove bolts E.
8. Remove the floor under cover No.2.
9. Remove bolts F.
10. Remove the fastener G.
11. Remove the floor ...
Front Seat Side Cover Removal/Installation
WARNING:
Handling a side air bag improperly can accidentally operate (deploy) the
air bag, which may seriously injure you. Read the service warnings in the Workshop
Manual before handling the front seat (side air bag integrated)..
If the sliding mechanisms on both sides are ...