1. According to the type of engine, the discharge of emissions into the atmosphere through an exhaust pipe is different. We can reduce the emissions by the use of catalytic converter. Even the catalytic converter is used, itself casing the problem of increasing the back pressure.2. The emissions and the back pressure are identified at different speed. the back pressure exerted by the catalytic converter during the working condition causes the decrease the volumetric efficiency and it leads to increasing fuel consumption.3. So here the back pressure is reduced by using the air box, by which atmospheric air enters into the exhaust emissions will increase the performance of the engine as well as performance and durability of the catalytic converter.