The demand of Torque from an engine is highly variable, good torque at lower engine speeds improve drivability at city driving condition and good torque at higher engine speeds improves cruising at highway driving, conventionally engine produces better torque at one particular speed leaving poor drivability at others. The Torque characteristics of an engine depends upon the volumetric efficiency of the engine, volumetric efficiency of a naturally aspirated engine can be improved by tuning the intake manifold.For improving volumetric efficiency, several technologies were developed, among that Dual Intake Manifold system is one where the flow of charge is channelized between longer and shorter flow path depending on the engine operating speed. Application of conventional Dual Intake Manifold system is limited due to increased cost, complexity in assembly and need for an external power source for actuation.In this work a novel Dual Intake Manifold system is designed in which the charge is channelized between either of the two paths by a flap valve which is actuated based on the manifold pressure at different operating conditions namely lower and higher engine speeds. In this method a simple flap valves is used to channelize the charge and the actuation of valve is a self a regulating system, which works based on the manifold pressure and no external actuation mechanism or power is required, which further improves the reliability of the system. Experimental results have shown significant improvement in Torque and Power at lower engine speeds without any sacrifice of performance at higher engine speeds.