This master thesis has been developed at POWERTECH Engineering S.R.L., an engineering consulting company, specialized in the field of 1D and 3D CFD analysis, in collaboration with McLaren Automotive Ltd., high end performance car manufacturer. The subject of this thesis is a high specific output, V6, S.I. engine currently under development at McLaren Automotive Ltd., which will equip a future, high performance vehicles. Numerical simulation allows a significant reduction in the need for physical testing, which in turn reduces costs and cuts time to market. It has become an essential tool in the development and optimization of new engines. In this perspective, this project was developed using GT-SUITE, a 1D CFD software, which also includes extensive tools for mechanical simulation.