Is the Zizzing Sound When Deeply Pressing the Throttle in a Turbocharged Engine Normal?

[MilaMarie]

Turbocharged engines making a zizzing sound when the throttle is deeply pressed is normal; it's the sound of the turbocharger at work. A turbocharger is essentially an air compressor that increases the intake air volume by compressing air. It utilizes the inertial force of the exhaust gases expelled by the engine to drive the turbine in the turbine chamber, which in turn drives the coaxial impeller. The impeller then compresses the air delivered through the air filter's pipeline, pressurizing it into the cylinders. As the engine speed increases, the exhaust gas expulsion speed and turbine speed also increase synchronously, allowing the impeller to compress more air into the cylinders. The increased pressure and density of the air enable the combustion of more fuel, and by correspondingly increasing the fuel quantity and adjusting the engine speed, the engine's output power can be enhanced.