tkisling

I know and abide by putting premium gas in my TL because that's what it says on the gas tank AND in the manual. My question is why?

Are the engines 'high compression engines' and the higher octane is necessary or what? I'll continue to use the premium gas, I'm just curious about the reason(s) behind it.

TheOtherDave™

You've answered your own question.

The compression ratio of the engine — combined with the design of the head, strength of the reciprocating assembly, ignition timing and type of fuel injection system employed — determine the minimum octane level needed to eliminate pre-ignition (aka "knock").

If you were to run a lower than recommended octane level, the resultant "knock" would substantially increase wear on the top-most piston rings as well as the rod end bearings.

Most modern engines are equipped with a knock sensor that can retard ignition timing to prevent serious damage. That said, the loss in fuel mileage usually wipes out any benefit one might see from buying the cheaper low octane petrol in the first place.

tkisling

Thanks. I assumed there was a reason behind it, I just wanted to know what it is.

I appreciate your response.