According to Kelley Blue Book, octane is a colorless component that boils at high temperatures. Octane is added to fuels, including gasoline used in vehicles, to eliminate preignition in combustion engines. The higher the octane rating, which is a measure of a fuel’s ability to resist “knocking” or “pinging,” the less likely the fuel is going to explode unexpectedly. In fact, KBB notes that gasoline with a high octane rating can withstand more compression than gas with a low octane rating.
So what does this mean for the average driver when he or she arrives at the pump and has to choose between 87, 89 or 93 octane gasoline? Likely very little. The U.S. Department of Energy notes that most gasoline vehicles are designed to run on 87 octane gasoline. However, some vehicles are still designed to run on higher-octane fuel, so drivers should always consult their owners’ manuals to determine which octane is best for their vehicles.