Abstract: A tuneable exhaust pipe for an internal combustion engine having a baffle slidable longitudinally within the exhaust pipe at the upstream end a plug in the downstream end. The baffle and plug each have an opening for passage of exhaust gasses therethrough. The baffle defines a resonate chamber on each side of it. The chambers avoid turbulence and maintain the shock wave in the gasses so that the chambers cause an additive dynamic relationship calculated to cause a supercharging effect on the engine by increasing the internal pressures therein.