Twin turbocharger principle
When the driver steps on the accelerator pedal, the engine speed changes. Because the turbine and compressor have inertia, they cannot keep up with this speed change. This phenomenon is called “hysteresis”. "Hysteration" increases engine delay or reduces output power. This way, if you accelerate more quickly, you will feel that the engine is not getting stronger.
The use of twin turbocharging is a supercharged system with two independent turbochargers. When the engine is combined by two turbochargers, the intake efficiency is greatly improved, the supercharging effect is more remarkable, and the power is greatly improved.
On the other hand, when the engine speed is low, only one low-speed turbine works. At this time, less exhaust gas can drive the turbine to rotate at a high speed to generate sufficient intake pressure. When the engine speed increases, the high-speed turbine continues to work. Entering a state of high boost value provides a coherent power.
This twin-turbo technology can improve the "hysteresis" of turbocharging while improving engine power. However, the twin-turbo engine does not completely eliminate the "turbo lag" phenomenon. After all, the inertia of the turbocharger impeller still exists. In actual use, twin-turbo engines are usually equipped with on-line 6-cylinder or V-type engines with larger displacements.