Engine gas exchange processes are characterized by overall parameters. The volumetric efficiency is the most important of these parameters, and depends, in addition to fuel and operating variables, on the design of manifolds, valves and the ports of the engine. Moreover, the gas dynamics of the flowing gases including the pressure waves and the boundary layer thickness of the flow due to friction play an important role. A smart device is fitted to the exhaust pipe and used to improve the engine volumetric efficiency, power and fuel economy. This controlling valve takes its commands, depending on engine loading conditions, from signals of some sensors such as manifold air pressure, engine speed, air mass flow, and inlet air temperature. Hence, a suitable amount of air and fuel flow, achieves optimum performance conditions. Furthermore, this work was also intended to develop a neuro-fuzzy controller model for improving the performance of the spark-ignition engine (SIE) fitted with smart device. Experiments were carried out on a 4-cylinder, 1.8 L displacement volume, Mitsubishi engine using PID Controller. Full range of road-load test conditions were covered. A hydraulic dynamometer was used, in addition to a scan tool and exhaust gas analyzer. The obtained results show that using the smart device improves power by 3-21% and bsfc by 9-21% between 25% and 75% load. Whereas, the neuro-fuzzy-based controller enhances engine power (30% 60%) and reduction in brake specific fuel consumption (12%-35%) in comparison with the PID controller used in the basic engine. (C) 2015 Energy Institute. Published by Elsevier Ltd. All rights reserved.