BRA - VW Golf GTI Mk5/6 - BlackBoost Reference Adapter Suits VAG 2. 0 TSFI Engines Replacement Adaptor for Turbosmart VAG Valves Turbosmart's Boost Reference Adapters (BRAs) allow access to a reliable boost reference, without compromising the operation of the car's standard sensors and control systems. The BRA attaches between the vehicle's MAP sensor and the intake manifold, providing a pressure source to two ports, while still allowing full, uninterrupted pressure to the MAP