I know this is an old thread but I just read it and thought I would share some info from
Sunoco that might clear up some misconceptions.
Sunoco Race Fuels | Beyond Octane
Here is an excerpt from the above article:
"You might be surprised to learn that some of the highest octane fuels may also be some of the fastest burning fuels!"
Also, some of us go faster with 87 in N/A snowmobiles by a noticeable margin than if we were to use 93. 87 can make big power in some sleds with the right combination of
combustion chamber, compression and timing. 87 has as many BTU's as premium give or take depending on the batch and who is mixing it at the plant. I have seen no evidence or read any articles that state that premium fuel contains more BTU's than regular, ever.
This is an excerpt from the Consumer Energy Center...California:
"There is little difference in energy content of regular versus premium gasoline. They
both contain about 111,400 British Thermal Units of energy per gallon."
Regular Versus Premium Gasoline
I don't know where they come up with that number, maybe it is a California thing but the point is the BTU's are about the same in either premium or regular nationwide.
Here is an excerpt from Road and Track:
"The reason for this has nothing to do with energy content. In fact, depending on its
blending, a premium fuel may actually contain less energy per unit volume than regular. However, its potential for producing more power and enhanced mpg goes back to MBT and that knock sensor. If premium is recommended, this is the engine's optimal fuel. It'll run on regular—albeit with the sensor invoking ignition timing that's less than that associated with MBT. And with less than Best Torque, there'll be less performance and an mpg hit."
Premium Gasoline ? What Does Premium Fuel Do for Your Car?
Octane is simply resistance to detonation and nothing to do with how fast fuel burns or
how much energy it contains per volume.
I used to think of it differently like most of us probably do, or did at one time until
I started paying attention.
As far as timing goes in our cars, it is relative to the fuel we use. Just enough octane
to keep it from pulling timing is probably optimum. Works for me.
Hope some of this stuff helps.