This research evaluates the performance of the two most utilized light-vehicle engines in Tehran, Iran. This paper aims to assess exhaust gas emissions of blended ethanol-gasoline combustion in two of Iran's national engines, TU5 and EF7, at different engine speeds. For this, exhaust gases, including CO2, CO, HC, and NOx, are analyzed using ANOVA statistical analysis. Fuel samples with 0, 20, 40, 60, and 80 vol.% ethanol in gasoline are tested in the TU5 and EF7 engines at different engine speeds, i.e., 850, 1000, 2000, 3000, and 4000 rpm. Findings suggest that the amount of exhaust gases is majorly dependent on the engines' characteristics, particularly the air-to-fuel equivalence ratio. According to the experimental results, CO2, HC, and NOx emissions from the EF7 engine are higher than the TU5 engine at all speeds. CO is higher in the TU5 case, on the contrary. As per the variance analysis results, exhaust emissions are primarily contingent upon and influenced by the oxygen rate required for combustion, fuel richness, and cylinder temperature rather than the composition of ethanol-gasoline blends.