Lower MPG om high octane fuel?

[tcpty]

Originally Posted by 127.0.0.1

higher octane means less energy per gram of fuel

it only makes more power if:

you have higher compression engine that can make use of the
(obviously) bigger injectors, higher air/fuel compression pre-spark and pack
more air in (bigger intake, forced air induction)

or

if you have a normal motor, but it is running crappy or has deposits
on the cylinder, or for whatever reason the knock sensor is always
retarding the ignition...then high octane might make the knock sensor
quiet down and you'd get better overall performance. But this
is treating a symptom not fixing the root cause


High octane fuel in an engine that doesn't need it is a waste of money
and you get less mpg


all high octane does is, it has less tendency to detonate at the higher compressions,
[so you can squeeze the crap out of it and then light it]. Now you get more power and
speed, and perhaps the same MPG. but without high comp pistons, and special
intake mods (turbo-blower) and an ecu designed for it...you will only end up with less
power and less mpg with high octane.

RIGHT ON THE MONEY!! EXCELLENT EXPLANATION !! KUDOS!!