Is it worth it to use premium fuel?

[MoVolvos]

I don't agree with your definition of Stable Fluid which included it's not about better mileage and power.

Not my definition, I included sites, that know better then we do, that use the same term. Octane is a measurement, not an ingredient. It's a measurement of fuels ability to withstand pre-ignition under high pressure and heat, i.e stability.

So saying it improves gas mileage is very misleading. In our engines, higher octane maybe prevents loss of mileage because the engine isn't retarding timing to avoid damage.

To the OP, if you run regular fuel and you car is not retarding timing, then you will receive the same gas mileage. If your car is losing mileage on regular your engine is retarding timing to protect itself from damage due to knock. If your Volvo requires 91/93 octane, that is because there is concerns the engine will have to retard timing to prevent knock or pre-ignition, aka engine damage. You can run a regular octane as long as the car can retard timing enough to prevent knock. Under these condition you will see a loss of mileage and performance, but if timing can't be retarded enough to prevent knock, it will damage your engine. This is why saying high octane improve gas mile is very misleading. The engine is retarding time to prevent knock, knock is very damaging to the engine. The loss of mileage is a side effect of retarding timing. Octane has no impact on mileage, any change in mileage is a side effect of the engine trying to prevent damage.

Octane is only a measurement of the fuel stability, any mileage gains/lose is a side effect of the reason stated above.

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No one tracks or can track nor need to track what you are purporting and that is pinging as the major factor in MPG. There are way way too many factors for just one individual such as the condition of the car, geographic and driver's habits that could lead to MPG change.

Given all things equal. With just one person in their daily weekly, monthly driving habits in one car, if the person used 87 vs 91 the following would occur, regardless of the half full or half empty cup reasons we create to explain it, the results will be the same. Cleaner and more complete burning, smoother running engine, increased longevity of the engine, higher MPG and better butt feel / driving experience. For some the extra cost is not worth it but for others it's a win, win in totality with too many pros that are not quantifiable.
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[velorider]

"No one tracks or can track nor need to track what you are purporting and that is pinging as the major factor in MPG"

I don't think " no one can track", perhaps you can't because you don't have an understand what octane rating is and why there are different grades. Without that understanding your statement are equivalent to the ancient people of earth trying explain what they see without the understanding of how things work.

[MoVolvos]

"No one tracks or can track nor need to track what you are purporting and that is pinging as the major factor in MPG"

I don't think " no one can track", perhaps you can't because you don't have an understand what octane rating is and why there are different grades. Without that understanding your statement are equivalent to the ancient people of earth trying explain what they see without the understanding of how things work.

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Please explain with source reference how to and who has tracked Octane & Pinging together while relating it to MPG. Thanks.
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[abscate]

Bob is the oil guy is a good website to have these discussions.

Fair warning about non MVS auto websites. You are leaving the Adult Sector