A supercharged internal combustion engine comprising: - a motor unit including a head and an exhaust manifold, - a turbocharger assembly fluid dynamically connected to said exhaust manifold, wherein said turbocharger assembly includes a turbine with a turbine body, a central body and a compressor with a compressor body, wherein - said turbocharger assembly comprises a lubrication channel for the passage of a lubricating fluid hydraulically connected to a lubrication circuit of said motor unit of said internal combustion engine, - said turbine comprises a jacket, provided at least in part in said turbine body, arranged for the passage of a cooling fluid and in hydraulic communication with an inlet channel and an outlet channel hydraulically connected to a cooling circuit (239, 240) of said motor unit of said internal combustion engine, - said inlet channel, outlet channel (42, 234B) and lubrication channel being integrated in said turbocharger assembly in correspondence of a connection interface between said turbocharger assembly and said motor unit of said internal combustion engine, - said turbocharger assembly is separated from said motor unit (201; 203) and is arranged for a mechanical connection to said motor unit (201, 203; 209, 248), - said central body comprises a cavity (24, 224) wherein a rotor assembly of said turbocharger assembly (4, 104, 204) is housed, and wherein said rotor assembly comprises a first impeller rotatably mounted within said turbine body, a bearing pack and a second impeller rotatably mounted in said compressor body, wherein said first and said second impellers (22, 25) are connected in rotation by means of a shaft, the internal combustion engine being characterized in that the central body, the turbine body and the compressor body are made in a single piece, in that said rotor assembly is arranged for the insertion in axial direction into said turbocharger assembly, and characterized in that said bearing pack comprises a sleeve including annular grooves (28, 29, 30) in hydraulic communication, by means of radial channels (31A, 31B, 31C) with an internal cavity provided in said sleeve, wherein said shaft is inserted in said internal cavity rotatably supported by a bushing. - a motor unit including a head and an exhaust manifold, - a turbocharger assembly fluid dynamically connected to said exhaust manifold, wherein said turbocharger assembly includes a turbine with a turbine body, a central body and a compressor with a compressor body, wherein - said turbocharger assembly comprises a lubrication channel for the passage of a lubricating fluid hydraulically connected to a lubrication circuit of said motor unit of said internal combustion engine, - said turbine comprises a jacket, provided at least in part in said turbine body, arranged for the passage of a cooling fluid and in hydraulic communication with an inlet channel and an outlet channel hydraulically connected to a cooling circuit (239, 240) of said motor unit of said internal combustion engine, - said inlet channel, outlet channel (42, 234B) and lubrication channel being integrated in said turbocharger assembly in correspondence of a connection interface between said turbocharger assembly and said motor unit of said internal combustion engine, - said turbocharger assembly is separated from said motor unit (201; 203) and is arranged for a mechanical connection to said motor unit (201, 203; 209, 248), - said central body comprises a cavity (24, 224) wherein a rotor assembly of said turbocharger assembly (4, 104, 204) is housed, and