Duncan writes:

My daily driver is a 2013 Hyundai Genesis 5.0 R-Spec (with about 22,000 miles), making a claimed 429 hp on premium gas (91 octane, I assume). The power dips to 421 hp (claimed) when running on regular. Here in Iowa, we have the luxury of purchasing fuel with no ethanol.

The 87 octane gas w/o corn costs almost as much as 91 with. If it was your money, what would you put in the tank? 87 with no ethanol ($2.40ish a gallon), 87 with ethanol ($2.20ish) or 91 with ethanol ($2.50ish)? Running 87 or 91 without ethanol does improve mileage, whereas I do not notice an increase in performance running 91 or 93 — though it is recommended (but not required) by the good folks at Hyundai.

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David writes:

Hi Sajeev,

Is it worth the extra 40¢/gallon to go for 91 octane ethanol-free gasoline based on its durability merits?

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