What is the function of a car blow-off valve?
2 Answers
The function of installing a blow-off valve in a car is to ensure that the boost pressure remains near the specified value, preventing engine damage and keeping the pressure in the intake manifold below the limit. Working principle of a car blow-off valve: Intake blow-off valve: After fuel return, it releases the pressurized air before the throttle valve; Exhaust blow-off valve: Under continuous boost conditions, to prevent turbo overpressure and engine knocking, it releases a small amount of gas to maintain turbo pressure. Methods to relieve pressure in a car fuel system: You can turn off the ignition switch, cover the fuel line connection with a cloth and loosen it with a tool to relieve pressure; Alternatively, you can remove the fuel pump relay fuse and start the engine for a few seconds to relieve pressure; There is a pressure test valve on the fuel inlet line before the rail. Turn off the ignition switch, cover it with a cloth, and press down on the pressure test valve.
The blow-off valve plays the role of a guardian angel in turbocharged engines. When you step on the accelerator, the turbo compresses a large amount of air into the engine. The moment you suddenly release the throttle, the throttle valve closes, but the turbo is still spinning at high speed, generating excess pressure. The blow-off valve is designed to release these high-pressure gases, preventing airflow backflow that could damage the turbo blades. I've been driving a turbocharged car for over two years now, and without this little device, the least you'd experience is sluggish acceleration, while the worst-case scenario would be a completely ruined turbo. Especially during aggressive driving, you can even hear a 'psssh' exhaust sound the moment you let off the throttle—that's the blow-off valve in action. With long-term use, you'll also notice that it effectively reduces turbo lag.
