In a pursuit towards improving the fuel efficiency and carbon di-oxide (CO2) control, the paper shall be confined to optimize exhaust systems to have a reduced back pressure (BP) output which has a direct influence on fuel efficiency. This objective is achieved by an experimental study and to reduce the huge number of iterations; Design of Experiments (DoE) technique is used which shall pave way for reduced number of experimental analysis on different setups of exhaust systems. Results are achieved using Flow Analysis-Flow Lab and Engine Lab with constant inlet mass flow rate and inlet temperature (engine conditions). This methodology shall give a direct behavior of different exhaust setups for the same engine conditions and the exhaust system setup that achieves the most reduced BP output shall be chosen as the optimized assembly.