What does the red zone on the tachometer mean?

[MacBentley]

The redline RPM indicates that the car's speed has reached the red zone on the tachometer. If the engine remains at high RPMs for an extended period or exceeds the redline, the temperature inside the cylinders will rise sharply, leading to increased pressure and potentially causing engine seizure. Additional details include: 1. Most car engines are equipped with a fuel cut-off protection feature. This means that after the engine runs at high RPMs for a certain duration, the onboard computer will automatically cut off the fuel supply to prevent excessive load. Fuel cut-off does not mean the engine shuts off; instead, the engine will not respond when the accelerator is pressed, and fuel supply will resume only when the speed drops to a reasonable range. 2. Occasionally revving the engine to the redline on the tachometer does not harm the car. However, if this continues for 3-5 minutes or longer, even the best cars can suffer engine damage due to excessive strain.