My perception on real gas

I don’t know how you measure your turbo not working as hard, but your engine running smoother is very possible.
With today’s engine controls, timing will advance until the knock sensor(s) pick up a signal at which time ignition timing will stop advancing or re-tard the timing. Advancing the timing can produce more power and better performance. Using a higher octane fuel will allow the ignition timing to advance farther before the knock sensors start picking up a signal.
Maybe that’s why your engine felt as though it was performing smoother.

philh wrote:
As an engineer, I hate "feelings" not supported by hard data.

1/4 tank left, went with premium. With tank down to 1/4 again, came across a station offering 93 ethanol free and filled it up again. started climbing the hills between SC and NC. Filled up again at another station in NC and proceeded over the mountain.

I perceived the turbo working a lot less and engine just seemed to be smoother. Not the experience I was expecting.

I don't know if it's my understanding or your reporting but I'm not grasping what you're trying to say? Your first tank was premium; second tank was 93 ethanol free; third tank was ??? And the engine ran smoothest on which fuel?

Well so far a lot of feelings but no data to support the feelings. Did you get better mileage based on cost per mile? Was the extra mileage worth the extra cost? I have no qualms about real gas being better but at 30-50 cents a gallon more is it worth it? For small engines like lawn mowers and leaf blowers perhaps.

“Feelings?” National Enquirer and Car and Driver report “feelings” regarding unknown vehicles.

There's is no comparison. Non ethanol gas is much better for performance and mileage than gas with ethanol added. When I had my V-10 Excursion I filled with 93 non ethanol when ever I could. Always felt like I picked up another 30HP when I did. And I gained noticeable fuel mileage.

philh wrote:
As an engineer, I hate "feelings" not supported by hard data.



I perceived the turbo working a lot less and engine just seemed to be smoother. Not the experience I was expecting.

Then as an engineer, what you perceive is just a "feeling" until you prove it! lol

What were you driving?