I figured it was a marketing gimmick to get you to buy 88 and then they would finally raise the price, but it’s been years. are they adding extra ethanol or something?

  • pelletbucket@lemm.eeOP
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    2 months ago

    okay so I had AI do the math for me.

    the 88 octane fuel with 15% ethanol would need to be approximately 4.7% cheaper than the 87 octane fuel with 10% ethanol to compensate for the lower fuel efficiency caused by the higher ethanol content.

        • FiskFisk33@startrek.website
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          2 months ago

          E10 has an energy density of 108,608 BTU/gal and E15 has an energy density of 106,814 BTU/gal.

          source: http://www.airimprovement.com/reports/national-e15-analysis-final.pdf

          This gives us tha the 88 octane has 106.8/108.6 ≈ 0.983 times the energy density of the 87.

          1-0.983 = 0.017

          The correct number is that the 88 needs to be 1.7% cheaper than 87 to give equivalent distance per dollar.

          LLMs are fantastic tech, good at many things. Math is not one of those things.

          • pelletbucket@lemm.eeOP
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            2 months ago

            yeah that’s why I labeled it as ai. like I can figure it out as a word problem to tell somebody, but I can’t figure out the math from there

            I didn’t feed it the energy density of e10 vs. e15, I just told it that ethanol was 30% less efficient, and gave it the percentages.

            • TheGalacticVoid@lemm.ee
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              2 months ago

              The AI does nothing with the percentages because it is an LLM, not an AI designed for math. All an LLM does is take a small number of words and turn them into a different set of words. It does not use your small set of words to run any formulas on your behalf.