Fuel, put regular unleaded in tank instead of premium

Hello,

This is a common urban myth that is circulating out there about gasoline octane ratings. Gasoline is gasoline is gasoline. The difference between 93 octane and 87 octane gasoline is it's resistance to detonation under compression. Octane is 100% resistant to detonation under compression and heptane is 0% resistant to detonation under compression. 87 octane gasoline is gasoline that under compression acts like is made of 87% octane and 13% heptane. 93 octane gasoline, you guessed it, acts like it's 93% octane and 7% heptane. Most cars manufactured today are not high compression engines and do not require more than 87 octane gas. Cars that are supercharged or turbocharged require higher octane gasoline because the air fuel mixture is being stuffed into the cylinders, the volumetric efficiency on the vehicle's is well over 100%. A supercharged or turbocharged vehicle that reaches 14.7 lbs of boost is putting double the air fuel mixture into it's engine's cylinders(and getting double the horsepower out of the engine) so it is very suseptable to detonation and requires the highest octane fuel available to be run in it.
What is detonation? Detonation is a very damaged event and is more commonly referred to as "knock". This happens when the air fuel mixture spontaneously combust in your vehicle's engine combustion chamber without the spark plug igniting it. The piston is still in it's upward travel in the compression stroke and the air fuel mixture goes off like a stick off dynamite. The "knock" you here is the detonation of the air fuel mixture "slapping" the piston on it's upward travel and can do major internal damage to your vehicle's engine. This is why vehicle's have knock sensors to retard the vehicle's timing when detonation is detected. There are other ways to prevent this outside the scope of this discussion.
Anyway, you are fine, and if you are buying premium gasoline because you think it makes your car run faster, stop. You are just throwing your hard earned money away.

Thanks,
Alex
2CarPros