At low engine speed, the longer manifold path can help to "press" more air into the cylinder before the valve closes, thus improving the torque output and making the vehicle start and climb more powerfully.
The intake manifold is where the fuel nozzles are installed. It provides an ideal space for fuel and air to be fully mixed before entering the cylinder to form a uniform combustible mixture, ensuring efficient and clean combustion.
It distributes the single airflow from the throttle to the intake valve of each cylinder smoothly and evenly, ensuring that each cylinder can get the same amount of air (or mixture), which is the basis for the stable operation of the engine.
At high engine speed, the system will switch to a shorter intake path. This reduces the intake resistance, allows air to flow into the cylinder in large quantities more quickly, and meets the intake demand at high speed, thus improving the maximum power output.