Forced air induction system
Turbocharger known as a turbo, Magna charger, or supercharger is a turbine-driven forced induction device that increases an internal combustion engine's efficiency and power output by forcing extra compressed air into the combustion chamber
A wastegates job is to control boost pressure.
To prevent over boost and severe engine damage, most turbocharger system uses a wastegate. A wastegate is a valve similar to a door that can open and close.
It is a bypass valve at the exhaust inlet to the turbine, which allows all of the exhaust into the turbine, or it can route part of the exhaust past the turbine to the exhaust system.
If the valve is closed, all of the exhaust travels to the turbocharger. When a predetermined amount of boost pressure develops in the intake manifold, the wastegate valve is open.
As the valve opens, most of the exhaust flow directly out the exhaust system, bypassing the turbocharger.
When less exhaust flowing across the vanes of the turbocharger, the turbocharger decreases in speed and boost pressure is reduced.
When the boost pressure drops, the wastegate valve closes to direct the exhaust over the turbocharger vanes to again allow the boost pressure to rise.
The wastegate operation is a continuous process to control boost pressure.
The wastegate is the pressure control valve of a turbocharger system.
Some of today's cars the wastegate is usually controlled by the Powertrain Controlled Module (PCM) through a boost control solenoid.