The rapidly growing consumption of petroleum-based fuels causes the government to expend a significant source of foreign currency on oil imports, which impacts the trade deficit in the government’s current account. The purpose of the feasibility is to see how unleaded fuel blends impact the performance of an unmodified engine operating on numerous blends. This testing was performed using a four-stroke, single-cylinder, water-cooled multi-fuel engine (Computer controlled variable compression ratio multi-fuel injection, kirloskar type engine) with a carburetor fuel injection system. Multiple parameters such as brake thermal efficiency, brake power, engine torque, brake mean effective pressure, and brake specific fuel consumption were assessed throughout the benchmarks.Regular unleaded blends with multiple fuel proportions have been used in these investigations. Six ethanol blend fuels were tested and their physical and chemical characteristics were analyzed, with 90 octane numbers achieved using unleaded fuel at E0, E5, E10, E20, and E40, along with variations in compression ratio. Research experiments were carried out at various different pressure ratios of 10.5:1 and 12:1, with engine speed calibrated to 1500 rpm. The findings demonstrate that blending unleaded fuel with a fraction of ethanol enhances the efficiency of the engine, such as brake power, torque, and brake thermal efficiencies and fuel consumption, thereby reducing brake specific fuel consumption. While compared to other proportions, the E20 (Ethanol 20%) ratio delivered the best brake power versus speed.