What does an octane rating tell?

Answer 1

The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When fuel ignites from compression rather than the spark from the spark plug it causes knocking in the engine which can damage the engine. For this reason you should use the octane as recommended by the manufacture. Using a higher octane than is recommended will provide no benefit whatsoever and it s waste of money. But using a lower octane than is recommend may cause damage. On modern cars with sophisticated fuel management systems the ECU may adjust for a lower octane fuel than is required so you may be able to use a lower octane at the expense of power and fuel mileage. Ask your dealer if it is safe to use a lower octane fuel before doing so.