The Master Thesis has been carried out in POWERTECH Engineering S.R.L., important consulting company specialized both in 1D engine simulation and in 3D Computational Fluid Dynamics, in collaboration with Aston Martin Lagonda. The subject matter of this research, performed using the software “GT-SUITE”, is the Detailed Model of a Spark Ignition Turbocharged Engine provided by Aston Martin Lagonda. The goal of the study is to obtain a Fast Running Model (FRM) capable of replicate with very good accuracy the performances at Full and Part Load of the original one. After the calibration and validation procedure in steady state conditions, the obtained FRM is further tested in transient conditions, by simulating some “Tip-In” maneuvers, in order to verify that FRM dynamic-response is coherent with the Detailed Model.