ethanol free fuel - who uses it

Discussion in 'Fuel Economy' started by TheStepChild, Apr 11, 2012.

  1. some_other_dave

    some_other_dave Well-Known Member

    The only problem you'll run into running 91 in an engine made for 87 is the extra cost. 4 points isn't enough to cause any trouble.

    If you were talking ~30 points, then you might wind up with trouble.

  2. RedylC94

    RedylC94 Well-Known Member

    That's right.
  3. 08EscapeHybrid

    08EscapeHybrid Moderator

    It is common in some areas to have ethanol free 90 or 91. If you take 91 E0, and dump ethanol in it to make E10, you end up with 94 octane E10.
  4. roothorick

    roothorick Active Member

    It won't *break* things but it's out of spec for the PCM tuning, which will hurt power and efficiency. I'd hate to load up on E0 91 at ~$8 more per tank only to find my fuel economy is significantly worse.
  5. 08EscapeHybrid

    08EscapeHybrid Moderator

    All things being equal, the lowest octane approved by the vehicle manufacturer will yield the best economy. However when comparing 87 E10 to 91 (or greater) E0, I find that the E0 still yields better economy than the 87 E10.
  6. DaveJ

    DaveJ Well-Known Member

    My finding on 3 cars also.
  7. some_other_dave

    some_other_dave Well-Known Member

    It would be very odd if it were significantly worse. I might expect slightly worse, or no measurable difference. But a significant drop would be odd.

  8. RedylC94

    RedylC94 Well-Known Member

    Right, if you measure "fuel economy" in gallons (or liters), but not if in dollars.

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