Originally Posted by tjdonahoe
The idea that lower octane gasoline is lower quality is dead wrong. It has more btu's per pound than premium You are susposed to use what your engine was designed for.
If you have a Ecoboost or other high output small displacement engine you need to read your manual as this engine was designed for maximum performance with premium but will operate with regular with reduced power output.
Premium actually contains less BTU than regular and is designed to burn slower and at higher compression reduce pre-detonation thus allowing for more ignition timing advance and power output.
Burning premium in a normal non turbo or supercharged low compression engine will have no benefit.
So those who choose to burn regular in engines designed for premium are reducing their engine performance ,lowering their mpg and reducing their engine life while pinching pennies.