As a promising concept to improve efficiency of a long-haul heavy duty truck with diesel engine, organic rankine cycle (ORC) based waste heat recovery system (WHR) by utilizing the exhaust gas-es from internal combustion engine will be paid increased attention in recent years. The greatest achievable global efficiency may be however restricted by the engine. On the one hand influences the engine operating conditions the exhaust gas temperature and quantity as waste heat source, and on the other hand limits the engine cooling system the heat rejection from condenser of WHR system. This paper aims to evaluate the impacts of the varied engine applications considering the affects of WHR system on the global efficiency and engine emissions. A complex 0D/1D-simulation model for a turbocharged production heavy duty engine with low-/ high-temperature cooling cir-cuit and a WHR system with ethanol as working fluid have been in GT-Suite established. The WHR system recovers the heat from high pressure exhaust gas recirculation as well as exhaust gas after turbocharger. The engine parameter studies have revealed the engine-related restrictions for the global efficiency under various engine operating conditions. A comparison of one-/two-stage tur-bochargers considering the recovered exergy and an investigation of different integration posi-tions for the WHR system condenser with respect to the heat rejection potential have been carried out. This paper differs from the most current researches on ORC based WHR system by it, which it focuses upon the engine performance changes regarding the integration of WHR system rather than the control and optimization of WHR system for a fixed engine configuration.