Currently the turbocharging is actively used in piston engines to increase their technical and economic indicators (from automobile to diesel locomotives and ship engines). The efficiency of piston engines with turbocharging significantly depends on perfection of processes in the intake and exhaust systems. Results of experimental researches of unsteady gas dynamics and heat transfer in the intake system of the piston engine with a turbocharger are presented in the paper. Studies were conducted on full-scale model of the single-cylinder engine with a turbocharger. It is shown that significant pulsations of pressure and flow occur in the intake system of the combined engine during the entire working cycle. The method of stabilization of flows in the intake system due to the controlled discharge of excess air after the turbocharger is proposed. A design study of the intake system with a pneumatic valve for diesel locomotive used on the railway transport of the Russian Federation is presented. This method will reduce the difference in the cylinders of multi-cylinder engine, reduce noise, increase reliability, and increase the efficiency of the turbocharger.