Octane vs MPG, 87 vs 93, anyone compared?

[James K]

The PCM modifies timing to curb power output when the knock sensor fires. This indicates detonation is occurring, and the PCM will retard timing (and power output) to prevent it. But it only does this at high power demand. There's no advantage to changing timing at lower power demand when detonation is not occurring, otherwise the PCM would do so ALL the time, not just when using premium.

All Ford Ecoboosts use a dynamic multiplier known as Octane Adjust Ratio

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[Mark S.]

We don't operate only at the bottom of the motors capacity.

No, but we--or at least I--operate the overwhelming majority of the time well below the power demand where detonation is likely to occur. And in situations where you will get the absolute BEST fuel economy (highway cruising) power demand is less than 20% of max power. The primary benefit of premium is that it requires higher temperature and pressure to ignite. I can think of no engine management strategy capable of using that advantage to increase efficiency below 20% of max power.

While we can't take your deposition on your real world experience on this subject (you having a hybrid and all) I'd be happy to give mine.

I don't have a hybrid. I don't even have a Maverick; I have a Bronco Sport with the 2.0L. I monitor this forum because the Maverick community seems to be a bit more enthusiastic about their cars than the folks over at the Bronco Sport forum.

Also, I have real-world data to back up my claim. I've been hand-computing fuel economy for my car since day one. For my use pattern (roughly 50/50 city/highway), there is no significant difference in fuel economy between regular and premium. You can view my data over on the Bronco Sport forum.