The ever-increasing emissions restrictions on internal combustion engines have led researchers into the study of alternative fuels solutions. As hybrid and electric vehicles started becoming more and more present in the markets worldwide, the popularity conventional internal combustion engines started to decrease (we see this especially with diesel fueled engines). For spark ignition engines, alcohols and gasoline-blended mixes have proven to be attractive solution in the last years. Out of these alcohols we mention ethanol, methanol and butanol. Butanol is a promising solution because of its high oxygen content with the possibility of improving the combustion process and thus even reduce emissions. Butanol also has a high combustion speed and can potentially reduce the combustion duration while improving the overall thermal efficiency. High miscibility is another important aspect of butanol, allowing higher percentage volume of butanol to be mixed with gasoline. The additional oxygen content may also improve combustion stability thus reducing cyclic variability. The objective of this study is to determine what is the impact of fueling a spark ignition engine with a blend of 10% vol. n-butanol and 90% vol. gasoline. The study will look at combustion stability, variability, thermal efficiency and emissions. A baseline was established at fueling the engine with pure gasoline at an engine speed 2500 min-1 and engine load of 55%. After the baseline, the same measurements were done at fueling with a blended mix of n-butanol and gasoline.