Premium fuel is for high compression engines. Premium fuel detonates at a higher temperature. A higher compression engine compresses the fuel air mixture more before the spark plug sparks. When things are compressed they heat up. If you compress an air fuel mixture enough it will get hot enough to detonate before the the spark goes off causing pre-ignition. So, now you have an explosion in the combustion chamber before the piston was in the correct spot. Our engines are not high compression engines and therefore will see no benefit from a high octane gasoline. Another misnomer is that premium gas has more energy per unit... it does not.