Manual Boost Controller
From WikiLEC
A Manual boost controller (MBC) is a bleed valve located between the Waste Gate Actuator and the Boost Control Frequency Valve.
It's purpose is to interfere with the ECU's control of the Waste Gate, increasing the amount of boost pressure being fed into the engine by the turbo.
Invariably combined with either a Fuel Cutoff Defender (FCD) or re-programmed ECU Memcal (chip) to overcome the inevitable fuel cutoff applied by the ECU to protect the engine - see Turbo : Increasing Boost.
