Since this is a gasoline related question, decided to post it to the engine related subforum.

This is not a question of which grade works fine with the engine nor is it a why-am-i-getting-low-mpg qns .

I (newbie) was curious as to whether a higher grade gasoline (eg 93 or even 97 in some countries) burns faster in the engine than a lower grade (eg 87) hence resulting in an mpg usage difference. Of course this is hard to tell in daily driving but I am asking about it more in a controlled testing (eg. in the lab)

If it does burn faster but doesn't result in a noticeable change in mpg, then that's fine with me too.


Thanks experts!

 

grade =/= refinement. all gasoline from the same brand is refined to the same level, then octane boosters are added

 

Gasoline's octane ratings reflect it's RESISTANCE to burn. Higher octane ratings actually mean it's harder to ignite. ie.. why it's better at resisting detonation etc...

 

As far as MPG is concerned what's important is the BTU value of the gasoline per gallon.
E10 will be at least 3.3% lower than conventional gasoline.
Thinning out BTU is a time honored method of making a cheaper gasoline. Why diesel which has at least 10% more BTU than gasoline is more expensive.