A silencer is a device for reducing the amount of noise emitted by the exhaust of an internal combustion engine. Internal combustion engines are typically equipped with an exhaust silencer to suppress the acoustic pulse generated by the combustion process. The pressure and temperature of exhaust gases which flow past the silencer will be the direct cause for back pressure in engine. The engine power must be used to overcome the back pressure in the exhaust system. Performance of muffler under various operating conditions is generally obtained through an experimental testing of prototype. The availability of performance parameters for compressible flow is limited, and experimental testing can be cost prohibitive. In this case the computational fluid dynamics analysis provides better results. The capability of using computational fluid dynamics is a test to determine its viability for determining its performance parameters. The objective of the project is to analyse the flow characteristics of exhaust gases in the existing and modified design of muffler. The work is to focus on to optimize the design in order to have minimum back pressure and increased life of silencer. The computational Fluid dynamics analysis would be carried out by using CFD tool CFX. A comprehensive study would be carried out with the parameters such as pressure and temperature distribution, intensity of turbulence and fluid force at varying load conditions.