This paper focuseson the use of CFD in advancing the LPG/air blend development of a dual fueled IC engine (Diesel and LPG). LPG is introduced through a secondary gas tube to the intake duct of the engine, keeping up 45 point to the flow direction. The variations in the stream boundaries change the output of the engine. Thus there is apossibility for gas tube design to position it and to get an optimized performance. From the previous literatures, CFD tool can be utilized to streamline the gas flow boundaries to improve execution. Familiar programming has been utilized to tackle this issue and approved with trial results. The outcomes show that the streamlined flow boundaries by FLUENT demonstrate 3% improvement in performance of the engine and 11% decrease in NOx emission.