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/InstallationCylinder Head
Outline
With the adoption of the rocker arm (built into needle roller bearing), the
sliding resistance has been reduced.
With the adoption of the HLA, the valve clearance is maintained at 0 mm at
all the times.
The contact point of the rocker arm and cam is lubricated by ...
Rear Lower Arm Removal/Installation
WARNING:
Be careful not to allow the coil spring to fly off when removing/installing
the coil spring. Otherwise, the coil spring could fly off and cause serious
injury or death, or damage to the vehicle.
1. When working on the left side of the vehicle, disconnect the auto lev ...
Headlight Auto Leveling System
Outline
Automatically adjusts the headlight optical axis in response to changes in
load and passenger conditions to prevent blinding of oncoming vehicles from
headlight glare and to assure a range of visibility.
The AFS control module performs headlight auto leveling system fail ...