Abstract: The exemplary embodiments herein provide a system and method for maximizing the fuel efficiency of an internal combustion engine. The system includes an insert for placement in portions of an exhaust system downstream from the header but before the muffler. Inserts can also be placed within the intake system of an internal combustion engine in order to maximize fuel efficiency. Whether placed in the exhaust or the intake, an exemplary embodiment would not affect emissions compliance of the exhaust system and combustion engine.