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MAN 800 Fuel Burn chart?

Discussion in 'Cabo Yacht' started by MC02020, Jul 1, 2020.

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  1. MC02020

    MC02020 New Member

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    Have been trying to find online a fuel burn chart for MAN 800hp D2848 LE403

    Can anyone point me in the right direction?

    Trying to do work out a plan for canyon fishing and how far we can safely go, need for fuel bladder, etc.

    My prior boat was outboards so its new to me to not know exactly what I am burning for fuel.

    Thanks for the help!
  2. PacBlue

    PacBlue Senior Member

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  3. PacBlue

    PacBlue Senior Member

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    I see they ran they mechanical V-8's in some early models, here's some fuel data:

    upload_2020-7-1_12-34-41.png
  4. mapism

    mapism Senior Member

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    A fuel burn chart as we all think a fuel burn chart should be, as far as I know, does not exist for those engines.
    The one that PacBlue posted was made by the US MAN distributor, and it's what you can find also on boatdiesel website, but there are some (minor) mistakes in it.
    The following is the official MAN chart for that engine, and while it's the most accurate you can find, it's a bit "German", so to speak.
    In fact, if what you are interested in is how many GPH the engines burn at any given RPM, you can calculate that based on these curves, but it takes a bit of math.

    Regardless, there's a couple of important points to bear in mind:
    You can forget the "full load" curves which are meaningless, except at WOT and 100% load, and the best approximation you can get is by considering the so-called "prop demand curve".
    BUT, that is a purely theoretical curve, because the actual prop demand (which is what drives the engines load, hence the fuel burn) can be significantly different from a boat to another.
    And with mechanical engines, unless you install a fuel flow meter, your only chance to find out the real world fuel burn of your particular boat is through testing.

    [​IMG]
  5. mapism

    mapism Senior Member

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    Same block as the V8-800, but very different altogether, because the 900hp was the first common rail and fully electronic version.

    That said, if the OP boat is the same, that is an excellent reference, because it's reasonable to expect a very similar fuel burn at all speeds, with the only exception of a top speed possibly a bit higher in the 900 powered boat, courtesy of the higher power.
    But I don't think that could be worth more than a couple of knots - if that.
  6. MC02020

    MC02020 New Member

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    Thanks guys will try to digest this. We made a canyon trip this week and used a bladder to get our capacity up to 950, and then did our best to log hours at RPM ranges.

    Topped off when we got back so we know our total consumption and now trying to back into that to better project for the next trip

    Thanks!
  7. mrcina

    mrcina New Member

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  8. YachtForums

    YachtForums Administrator

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    PacBlue hasn't posted since Sept 2020 and he is missed by ALL of us. Hopefully someone else can supply a valid link.
  9. leeky

    leeky Senior Member

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    He hasn't posted since then, but he signed in at 9:07 PM Friday, Sept. 24, 2021. So, at least he's lurking.:D
  10. mapism

    mapism Senior Member

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    Here it is.
  11. mrcina

    mrcina New Member

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    Great guys!
    I am in the process of buying a Cabo 43 FB with C-12 engines, so this Cabo sea trials will help a lot.
    Thanks again for the quick response.