This work describes upgrading of an existing spark ignition engine. Upgrade means achieving more power without physical modification of the engine by using turbocharger with air cooling system for getting more power. The project analysis of engine is created in Lotus Engine Simulator software which give us results after we build up virtual engine and set up all input parameters. After debugging, the simulation is ready for run and obtained results contain detailed data of overall engine performance and thermodynamic and mechanical characteristics of its main parts. First part of this work describes main terms and properties used for evaluating and projecting turbocharged system. In the following part there are all calculation results with complete evaluations which has been done in commercial computer software-s. There are also drawings and 3D models about positioning of turbocharged system which are also made in commercial computer software-s for designing and 3D CAD modeling.