Wastegate: Description and Operation

Turbocharger And Wastegate Assembly:

Wastegate And Frequency Valve Operation:

The wastegate, mounted on the end of the exhaust manifold, allows exhaust gas to bypass the turbocharger when the maximum allowable boost pressure is reached. This limits the turbocharger RPM and consequently limits boost pressure.

The wastegate is operated by intake manifold pressure (boost pressure). A vacuum/pressure hose is connected between the intake manifold and a diaphragm chamber in the wastegate valve. When turbocharger boost reaches a certain level, pressure acting on the wastegate diaphragm opens the valve. A portion of the exhaust gas is routed directly into the exhaust pipe through a small section of semi-flexible pipe. This reduces the amount of exhaust gas going through the turbocharger limiting its rpm and boost pressure.