WARNING: FRIKKIN' NOVEL AHEAD!
I can read and the fact that you are claiming better gas mileage and power improvement just shows that you know nothing about what a higher octane gasoline is. It is not a more powerfull or explosive gas. It's not a better cleaner gas. The higher octane only means that it burns slower which is more resistant to detonation. A slower burn means that not all the gas is being burned in the combustion chamber leading to carbon build up in a stock timing engine. With the gas not being burned in the chamber that means your mixture is rich and you are getting less power. This is not like a normal rich condition where the o2's will see it and the computer will adjust. The raw gas is expelled into the exhaust and and burned in the header. This causes the o2 sensor to read lean which makes the computer add fuel leading to power decrease and mpg decrease. There is no way to gain mpg or hp by running 93 octane without a tune.
OK, see, I and other people have observed the same thing. We observe "reality," which trumps theory. If I was in your shoes I'd dispute our claims as well. But real-world testing is the observation of the physical world. No reputable scientist worthy of the label would argue with real-world observation. That's the cornerstone of the scientific method - form a theory, deesign an experiment to test the theory, execute the experiment, observe the results, and amend the theory to match the real-world observed results. Theory falls before reality. Whenever reality differs from theory, theory is wrong, NOT reality.
Most sources I find say higher octane doesn't burn significantly slower, it just ignites later under pressure and heat. In other words, it takes more pressure/heat to make it combust. A spark will ignite it the same as lower octane. Even if it burns slower, it's such a minor difference in the time it takes the flame front to advance it is a moot point. Most N/A engines only burn for the top 90* of crank travel regardless of octane requirement. It's all burned before the exhaust valve opens either way.
And let's just say you are right, it takes so much longer to burn. Therefore the crank travels farther around while the fuel is burning as a consequence. That just means more power is generated. As fuel burns it pushes the piston and crank farther around the circle. Once the all the fuel is burned, the resulting gasses start to cool and stop pushing on the piston. The farther you can push the piston during combustion the more power you make. F/I engines ideally push the piston down past 90*, that's how they make more power on the same displacement. You can't burn more gas in the same amount of time with the same size cylinder. It takes longer to combine more O2 and gasoline, so it pushes the piston farther around the circle and hence transmits more power to the crank. You just provided a valid theory on why higher octane gas makes more power - by burning slower
In addition, consider that a fast-moving flame front compresses the unburnt mixture in front of it, giving rise to the possibility of pre-combustion that may or may not be noticed in the midst of a combustion event, but wastes power. A slower-moving front gives less chance for this condition to develop and higher octane fuel makes this more unlikely, and therefore less power is wasted from pre-ignition during lower rpms, such as are encountered during cross-country travel. High-rpm operation gives little opportunity for knock or pre-ignition (in front of the spark-ignited flame front) so differences in octane due to knock or pre-ignition would be less noticeable.
I'm not endorsing the idea that higher octane burns slower, merely showing that if it did, the effects would be entirely beneficial. I don't know if it does, I just know my results of real-world testing.
In Minnesota (where I live) the only non-oxygenated gas is 93 octane. Oxygenated gas has less energy content than non-oxygenated, so mileage and horsepower WILL be higher with non-oxy gas. Oxygenated gas at first seems to be a benefit to power since the fuel is delivered along with a portion of O2, but mileage suffers because you are paying for a portion of a gallon of oxygen for each gallon of fuel. Non-oxygenated gas is "all fuel" and all the O2 is provided by the atmosphere, so you see higher mpg numbers. Power should not suffer during closed-loop where the O2 sensors have input, but during open-loop where fuel is dumped in according to a stoichiometric number, it probably doesn't assume a portion of the "fuel" is O2. So if open-loop operation at the factory assumes non-oxy fuel and you run oxygenated fuel, the engine actually delivers less fuel than the factory planned for and power output suffers. It's not that high octane contains more energy bacause of the octane number, it's that non-oxygenated fuel contains more energy and 93 octane is almost always non-oxy in MN.
Given that, a person in Minnesota buying non-oxygenated gas will see a mpg benefit over oxygenated gas, and a benefit at the dyno most likely. The extra cost for non-oxygenated fuel here means there is no monetary savings, but the mileage and power benefits are real.
Look, give it a try under conditions you consider valid. That's all you can do. You're not a fool, so you can come up with a valid test. It's called physics, the observation of the physical world.
I've done it and am convinced. You would be too if you just gave it a shot. I know higher octane isn't magic and doesn't contain more power just because it has higher number somewhere. I am unable to explain my results scientifically and unassailably, but that's because I observed them in a practical application with nothing to prove. I had as much motivation to see higher octane as a waste of money, but that wasn't what I found. I've stated before that I doubt it's a cost-effective way to spend your money, so it's not like I'm justifying the extra cost. It just happens that in my car higher octane results in real-world benefits.
Regarding higher octane burning slower, I refer to these pages (without endorsing them across-the-board - too much "garage science" and not enough "lab science"):
"The antiknock ability is related to the "autoignition temperature" of the hydrocarbons. Antiknock ability is
_not_ substantially related to:
---The energy content of fuel, this should be obvious, as oxygenates have lower energy contents, but high octanes.
---
The flame speed of the conventionally ignited mixture, this should be evident from the similarities of the two reference hydrocarbons. Although flame speed does play a minor part, there are many other factors that are far more important. (such as compression ratio, stoichiometry, combustion chamber shape, chemical structure of the fuel, presence of antiknock additives, number and position of spark plugs, turbulence etc.)
Flame speed does not correlate with octane. "
from
IMOC Articles - Octane ratings, fuels and water injection
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"A lot of people also confuse octane with flame-front propagation speed which is yet another independent factor. Take the old-days measurement of octane-ratings with iso-octane (2,2,4-trimethylpentane) with a octane-100 rating and n-heptane with a 0-octane rating. They both have the exact same flame-front speed, yet one of them has a fairly high anti-knock index. The other, n-heptane, has such low knock-resistance that you can just tap the beaker and the stuff would explode!"
from
Octane Rating - Thor Racing (Japanese Performance Car Tuning)
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Flame speed - Wikipedia, the free encyclopedia
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Your questioning of what I've found makes me question it. Yet the more I test it and the more I research it, the more convinced I am that my findings are not BS or wishful thinking. Believe me, if I could find a way to convince myself that cheap gas was as "good" as high octane, I'd be down with it. But at the end of the day, it seems you get what you pay for whether that was the original idea or not.
