Premium vs. Regular fuel fuel economy?

I am just wondering, if using premium fuel in the 2010 improves or decreases fuel economy. While it may be true that 87 octane fuel is actually more energy in the 91 octane fuel, the car might be able to advance its timing to more than compensate for the reduced amount of energy. Has anybody tried hypermiling using premium fuel instead of regular. I am not talking about fuel that is mixed in with ethanol however. I'm also curious if things have changed from the second-generation model. I am not talking about, whether the extra price is justified in terms of cost. I am just wondering if anybody has tried this, and what kind of results they found.

Sigh... Priuschat could have a full time moderator merging posts where the person was too lazy to search for the other dozens of threads on the subject.

No one has reported better mileage with Premium, some have reported worse. The guys doing hillclimbs, find a Horsepower increase with Premium.

I had to use premium in my Gen II a couple times where I ran into a gas station that only had premium. I didn't notice any increase in MPG.

This one is #3 on my special PriusChat keyboard. Numbers 1 and 2 are for "How long will your battery last?" and "Did you know that Hummers are more efficient than the Prius?"

Tom

no i didnt, but i do know that Hummers are "greener" than Pri's...

Darn it, now I have to go back and reprogram button #2.

Tom