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87 vs 91 (or 92) Octane?

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Comments

  • andysdandysd Posts: 87
    Okay, Steve, if you insist. Let us know when you and your wife come to San Diego, and we'll try Hob Nob, or take you to Phil's BBQ and fix up your cholesterol.

    I have got to get my act together and write C&D. Oldbearcat's last contribution negates the mpg improvement part of the fun, but horsepower increase was actually the starting premise. Also, I'm just about convinced that smoother engine performance is a side benefit.

    In addition to trying higher octane, I plan something else with my Fit. Since I thrash it at the red line in the mountains, I figured out a way to effectively gain about 5 horsepower - and improve cornering: am going to remove the rear seats, which I've read weigh over 100 pounds. That will improve the power to weight ratio by about 2,550 / 2,450 = 1.04, as if the horsepower were increased by 1.04 x 117 = 121.8.
  • steverstever Viva Las CrucesPosts: 41,309
    edited December 2011
    Now you're talking. Forget if the Fit has a spare. Even if it's a compact one, stash it in the closest and replace it with a can of Fix-a-Flat.

    That said, I lost 30 pounds in the last year and my mpg nor performance haven't improved (hasn't helped my car's mpg or hp either :P ).

    Moderator
    Minivan fan. Feel free to message or email me - stever@edmunds.com.

  • andysdandysd Posts: 87
    But you're on the right track, Steve. Lose another 70-plus pounds and then see!
  • Sorry I sunk your ship. IMO, the software upgrade will no longer let the engine take full advantage of the additional octane. I'm going to run a couple more tankfuls just to make sure. I have run into stations here selling 93 that was actually 87, and, the price differential is not that bad right now. I also did this exercise on a 2008 Saturn Aura (previous business driver) that was equipped with a 3.5 liter pushrod V6 with fairly high compression and VVT. Using 93 octane gas had no effect on its fuel economy.

    Regards:
    Oldbearcat
  • steverstever Viva Las CrucesPosts: 41,309
    edited December 2011
    That gets us back to the question of whether your engine, software flashed or not, is designed to take advantage of the higher octane. Do they still make winter blend fuel? Keep hearing reports that there's little need to change the blend anymore, with all the ethanol in most gas. But that would have hammered your last tank if it was "winter gas".

    But what do I know; another 70 pounds and I'll be a 90 pound weakling. :shades:

    Moderator
    Minivan fan. Feel free to message or email me - stever@edmunds.com.

  • andysdandysd Posts: 87
    With a final grasp at floating flotsam or jetsam, Oldbearcat, can you explain the 34.5 mpg run in the CR-V?

    Regards,
    AndySD
  • No, I can't - and, I've never been able to duplicate it since. I do take solace in the fact that, with both cars running on 87 octane gas, the CRV manages to get 4.5 more MPG than my stock 1948 Chevrolet Fleetmaster does.

    Regards & Merry Christmas

    Oldbearcat
  • andysdandysd Posts: 87
    Jan 9, 2012: I finally emailed the editors of Car and Driver, following:

    Dear Editors:

    In the light of European Car magazine's July 2010 positive result, this is to suggest you repeat your November 2001 test to determine whether using premium gasoline increases horsepower for engines that are not required to use it. The European Car test can be read on http://www.europeancarweb.com/tech/proven/epcp_1007_2010_volkwagen_jetta_proven/- viewall.htmlxx. In their test, using premium gas in a 2010 VW Jetta 2.5 L, dynamometer tests showed an increase of 8 horsepower!

    I started what became a lively forum thread on this subject on Edmunds.com, Gasoline - 87 vs Premium. There seemed to be unanimity that such engines felt peppier but did not conclusively increase miles per gallon. My 2011 Honda Fit Sport 5MT definitely feels stronger with premium, and I wonder whether engines with higher compression ratio, like my Fit at 10.4:1, benefit more. Considering your success with the Fit in the 25 hour Thunderhill race, I hope you might use the Fit in your test.

    As an aside, I love driving my Fit on the San Diego East County two-lane mountain roads, and it flies through the curves, more than holding its own compared to friends' expensive sports cars. I installed 17" Kosei Racing wheels with 215-.45 Kumho SPT tires left over from an '04 Civic, and removed the rear seats reducing weight by 70 pounds.

    Sincerely,
    Andy...
  • steverstever Viva Las CrucesPosts: 41,309
    Heh, since Edmunds competes with Car and Driver for automaker ad dollars and has their own forums, you might get the cold shoulder by mentioning our forums. :shades:

    Maybe they'll edit that part out and get back to you. :D

    Moderator
    Minivan fan. Feel free to message or email me - stever@edmunds.com.

  • andysdandysd Posts: 87
    Good point, Steve, but at least they have the whole story. Let's see if they do anything.
  • andysdandysd Posts: 87
    I started this thread after reading an article in European Car that showed a dyno increase in h.p. as the result of using premium gasoline where not required. In summary, I wrote Car & Driver to suggest they conduct another test, quoted in an earlier message.

    All to no avail, and I'm signing off. I don't know the answer definitively, and probably never will . C&D never reacted.

    RIP
  • steverstever Viva Las CrucesPosts: 41,309
    edited June 2012
    A journalist would like to speak to someone who fuels up with 85 octane and has experienced engine issues or a weaker performance at lower elevations because of it. If you use or have used 85 octane, and would like to share your story with a reporter, please send your daytime contact info to pr@edmunds.com no later than Wednesday, June 20 at 2 p.m. Pacific/5 p.m. Eastern.

    Moderator
    Minivan fan. Feel free to message or email me - stever@edmunds.com.

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