My perception on real gas

4x4ord wrote:
Ethanol has about 2/3 the energy content of gasoline. If your comparing 93 octane ethanol free to 93 octane E10 you'd expect the ethanol free gasoline to perform about 3% better. A 3% increase in fuel economy could maybe be measured but I don't believe any of us could "feel" a 3% gain in power or fuel economy. Any actual studies that I have read have found more like a 1% reduction in fuel economy and no change in power when using E10 fuel vs ethanol free gasoline. Some engines have been measured to perform slightly better on gasoline with ethanol.

I believe the perception the op had with regard to how his engine performs on one fuel vs another is about like someone saying he finds it easier to walk up a flight of stairs when he has waffles for breakfast vs pancakes.

^This.
And while the OP's perception may be just that, as the performance difference between premium with 10% corn and premium pure gas is literally minuscule, especially in a modern vehicle that monitors and changes fuel delivery to match or meet a set of parameters in real time.
OR, a marginal quality tank of premium ethanol blend vs a good fresh tank of non eth could yield an actual performance change that is seat of the pants perceptible.
Speaking strictly stock OE run of the mill vehicles, there is no real disadvantage to using the appropriate octane E10 that I'm aware of. If the fuel is used in due time and not left to sit and absorb more moisture than pure gas.

And in certain conditions (that Turtle more than alluded to, although blew out of proportion, like his 7 second street car or whatever that other thread was about) alcohol blends or oxygenated fuel has performance advantages.
But those advantages or the corresponding disadvantage of using the same octane pure gas are small until you start really playing with afr's, boost, timing, compression, valve timing/lift/duration, etc.

I have the same "perception" as the OP about using pure gas, although I know better except in applications where the fuel may sit unused a long time. Pure gas smells better, lol (it really does smell perceptibly different) and last longer. That is it's main advantage.
But by the same token, I was pumping a tank full of 92 ethanol free into the boat last year and it didn't "smell" right. Pulled a sample later and it was a bit yellow, and I "felt" the engine wasn't quite as responsive. Didn't leave me stranded, didn't cause other issues, but I burned through it and moved on with life. Based on that, I could say pure gas is not as good.

One thing I don't do is mess around with quality of fuel. But there are times that spending more money is actually worth it and times that it's just a perceived value.