WHAT IS A WASTEGATE?

A wastegate is essentially a valve which ‘wastes’ the gas pressure we don’t want sent into a turbocharger. When a wastegate is shut, all exhaust gases exiting the engine are forced through the turbo. This creates boost, which encourages more exhaust gases to be produced.

The turbo then spools even faster, creating yet more boost. By allowing some of the gases to bypass the turbo through a wastegate, we have control over how fast the turbo spools, which gives us the ability to control the amount of boost being generated. Without a wastegate, the cycle of increased boost pressure would continue until vast pressure forced mechanical failure. That said, some variable-geometry turbochargers (VGT) don’t require a wastegate thanks to aerodynamically shaped vanes in the turbine housing at the inlet. The vanes rotate in unison to vary the gas swirl angle. For the vast majority of turbocharged cars, however, a wastegate is essential forced induction componentry.