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/InstallationAirflow Mode Actuator Inspection [Full Auto Air Conditioner]
CAUTION:
If the lever position exceeds the operation range shown in the figure, the
circuit in the actuator could be damaged. Always perform an actuator operation
inspection with the lever movement within the range shown in the figure.
1. Connect battery positive voltage to airfl ...
Hydraulic Lash Adjuster (Hla) Removal/Installation
WARNING:
A hot engine can cause severe burns. Turn off the engine and wait until it
is cool before servicing.
CAUTION:
If the camshaft is rotated with the timing chain removed and the piston at
the top dead center position, the valve may contact the piston and the engine ...
Active Command Modes Inspection [Instrument Cluster]
1. Connect the M-MDS to the DLC-2.
2. After the vehicle is identified, select the following items from the initialization
screen of the M-MDS.
a. Select “DataLogger”.
b. Select “Modules”.
c. Select “IC”.
3. Select the simulation items from the PID table.
4. Perform the acti ...