Originally Posted by mishka
My friend said that because 93 octane (premium gas) has "less contaminants" , that's why it can "clean out" the car.
Yeah your friend doesn't know anything about gas, apparently.
The octane rating is based off the knock percentage in a test engine as a result of the ratio between heptane and octane in the fuel, along with other additives such as ethanol and detergents. "Regular", "Midgrade", and "Premium" and all of that garbage are just marketing terms, and marketing people are generally complete blithering idiots.