Turbocharger apparatus (1) comprising a housing (4), a compressor, a turbine (40), a first inlet (39) for enabling air to be conducted to the compressor, an outlet (36) for enabling air from the compressor to be conducted to an engine, a second inlet (53) for enabling exhaust gases from the engine to be conducted to the turbine (40), a chamber (96), a bearing assembly (82) for permitting the rotation of the turbine (40), and a control system (5, 10) for controlling the speed of the turbine (40), the control system (5, 10) having an exhaust gas sealing system (8, 21, 26) which prevents exhaust gas leakage from the turbocharger apparatus (1), and which allows expansion of parts within the exhaust gas sealing system (8, 21, 26) at high temperatures.