Refilled with non-ethanol 91 octane ...

[fnkngrv]

Originally Posted by Kar98

Gas with a higher octane rating will only improve your gas mileage if your car requires the higher octane rating because of a high compression engine like my VW Scirocco 16V. When I put in cheaper gas, it used more gas to compensate, and it ran like crap.

On the other hand, if your car is rated for regular gas, just use that, because you will not see an improvement in gas mileage.

Actually iirc even in the owners manual it states that you are not supposed to use non-ethanol gas whatsoever. Because of this alone regardless of the octane rating he very well may not be wasting money IF he gets that much better MPG out of it. I tried as much as possible when I was living in central AL to use the non-ethanol gas even though it was more expensive and usually after the first couple tanks netted on avg 3/4mpg better. Never bothered to do the math on the "savings" or "spending" but I can tell you that it ran better and I did get a much better response out of it. I really wish at this point that I would have been able to be tuned properly and had a solid dyno run to tell the difference if any between them. It just would have been intriguing to see if it were a placebo effect or not.