Abstract-This paper investigates the effect of using unleaded gasoline with di ethyl ether blends on spark ignition engine (SI engine) performance, exhaust and combustion analysis. A four stroke, single cylinder SI engine was used for conducting this study. Exhaust emissions were analysed for carbon monoxide (CO), Hydrocarbon (HC), and Oxides of nitrogen (NOx) and carbon dioxide (CO 2 ) using unleaded gasoline, ethanol and di ethyl ether blends with different percentages of fuel at varying engine torque condition and constant engine speed. The result showed that the blending of unleaded gasoline with di ethyl ether increases the octane number and power output this may leads to increase the brake thermal efficiency. The CO, HC and NOx emissions concentrations in the engine exhaust decreases while the CO 2 concentration increases. Using di ethyl ether as a fuel additive to unleaded gasoline causes an improvement in performance and significant reduction in exhaust emission.