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MPG B Mode Trick

Discussion in 'Gen 3 Prius Main Forum' started by Eve Barbanell, Mar 11, 2017.

  1. fuzzy1

    fuzzy1 Senior Member

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    bisco said:
    sign on 70 mph rt95 in southern virginia: driving over 80 mph is considered reckless.
    In my sleep-deprived state yesterday (after ten days of elder care and frequent overnight livestock care), I read bisco's post as 'under 80 mph' rather than 'over 80 mph'. Reviewing it after a full night's sleep, a correct reading of his post takes the steam out of mine.
     
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    Still, sadly: it can be reckless, obeying speed limits these days. :(
     
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  3. fuzzy1

    fuzzy1 Senior Member

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    That speaks strongly to the particular local driving culture. In highly competitive urban combat driving, that would be true.
    In other areas that have lighter traffic and have degraded less from proper defensive driving standards and safe following distances rules, a normal downshift is still a non-issue. Though the rapidly increasing brain-on-mobile-phone disease may yet change that.
    This is very strongly driver-dependent. Except for the Prius, my household fleet has been all manual transmissions for more than three decades. So far, clutches have lasted the full economic life of the cars, we have never needed to replace them.

    FWIW, we have unloaded past stick shifts at 130k, 130k, 235k, and 175k, all with original clutches still serviceable. The spouse's daily driver has 195k.
     
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  4. The Electric Me

    The Electric Me Go Speed Go!

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    Oh....
    Once again someone has embraced a peripheral magic spell that "B" mode supposedly casts.

    Well?
    My advice has always been and continues to be...just use "B" mode as it is described in your owners manual and by Toyota. Which is pretty much, just a mode used while going down long, steep inclines.

    I don't recommend using it as approaching stop lights...pulling away from stop lights...or any other combination of Voodoo rituals.
    My opinion is Toyota has spent a lot of time, money and energy designing The Prius over the course of a lot of years. That means hardware and software both designed to return efficiency and be safe.

    Thinking "we" have found a way to out think this reality, I think invalid.

    That's not to say, some hypermiling techniques aren't very valid fuel improvement actions.
    But "B" mode? IMO...it's just "B" mode. The propensity to evolve it into something it was not designed to do, I think a waste of effort.
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    I agree with everything you're saying, well except the above. And maybe that's the issue: Toyota is royally terse on the subject, and the knowledge of B mode here has been largely unsupported by Toyota.

    Do they say anything about reserving it for protracted downhills? Somewhere, a white paper or something? I think they should, and I do think extreme downhills are it's sole application. But this is all I see the Owner's Manual:

    upload_2017-3-13_11-57-3.png
     
  6. The Electric Me

    The Electric Me Go Speed Go!

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    I agree.
    Toyota could end a lot of the debate, with clearer revelation of exactly how, when and why.

    Hey, I could be wrong. I'll repeat it...I could be wrong.

    But my understanding of the ultimate application of "B" mode was....when going down steep inclines.
    Outside of those parameters, I've never read much feedback that Toyota recommended using it for any other application.
     
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  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Works for me, and is simple. Basically: Mount Seymour.
     
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