a turbocharged diesel engine is described . the engine has a two stage turbocharger assembly including low pressure turbochargers coupled and parallel and arranged in series with a single high pressure turbocharger . this allows all turbochargers to be of comparable dimensions for interchangeability of parts . the turbochargers may be mounted on an enclosure which encloses the turbines and the exhaust gas duct work which communicates with the exhaust pipe to insure that any leaking exhaust gas escapes to the atmosphere via the exhaust pipe . a cartridge is also described which contains the moving parts which can be removed without disturbing the turbine housing .