A boost controller is a device to control the boost level produced in the intake manifold of a turbocharged or supercharged engine by affecting the air pressure delivered to the pneumatic and mechanical wastegate actuator. A boost controller can be a simple manual control which can be easily fabricated, or it may be included as part of the engine management computer in a factory turbocharged car, or an aftermarket electronic boost controller such as those made by GReddy.
Read more about Boost Controller: Principles of Operation, Manual Boost Control, Electronic Boost Control, Dangers in Use, Past and Future