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Thread: octane question

  1. #1
    Join Date
    Aug 2012
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    Kaukanua, WI
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    Default octane question

    Hey guys -

    I am probably just being paranoid, but I have a fuel octane question. I have the 6.0L 409 HP Indmar engine and the owners manual says to run fuel with a minimum of octane rating of 91. I have about 40 hours on the boat and I have done this to this point. We are going on a trip and will need to fuel on the water, and based on a few phone calls to marinas on the water most carry 87 clear (no ethanol). Is there any risk in running a tank or 2 of this through my boat?

    Thanks,

    Luke
    2013 LSV

  2. #2
    Join Date
    Jun 2012
    Location
    Portland Oregon
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    805

    Default octane question

    Bring some bottles of octane booster with you.
    -Jake

  3. #3
    Join Date
    Feb 2011
    Location
    Monroe, WA
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    Default

    It takes quite a bit of octane booster to get that kind of increase. Read here:
    http://volvospeed.com/Review/misc_pe...o_reviews.html

    -J
    2008 Mobius XLV | 325HP | OJ 5-blade | 3300lb ballast

  4. #4
    Join Date
    Aug 2011
    Posts
    1,054

    Default Re: octane question

    It'll just run with less power and use more fuel... The computer will retard the timing with the lower octang...

    Sent from my Nexus 4 using Tapatalk 2
    2002 Moomba Mobius LSV - Sold
    2006 Moomba Mobius LSV

  5. #5
    Join Date
    Aug 2012
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    Default

    Listen for knocking. If you don't hear it (sounds like marbles in a coffee can) you are not hurting the engine at all.

    With knock sensors, you will almost never get detonation out of 87 octane.
    Nate

    2008 XLV GG (sold)
    2013 LSV

  6. #6
    Join Date
    Feb 2008
    Location
    Traverse City, MI
    Posts
    2,393

    Default octane question

    It seems odd that you can't find higher octane on the water - our lake has 87 with ethanol, and 91 without. I opt for the 91

  7. #7
    Join Date
    Jun 2012
    Location
    Portland Oregon
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    Default octane question

    Only 87 at Shasta. I run it. The MC gets booster.
    -Jake

  8. #8
    Join Date
    Aug 2012
    Location
    Kaukanua, WI
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    Default

    Quote Originally Posted by beat taco View Post
    Only 87 at Shasta. I run it. The MC gets booster.
    Hey Jake what octane does your engine call for? What booster do you use? I am hoping to find some higher octane on the water but I picked up a couple bottles of Lucas Oil Booster in case....

    -Luke
    2013 LSV

  9. #9
    Join Date
    Jun 2008
    Location
    De Pere WI
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    Default

    as mentioned above, there have been several car mag tests on octane boosters and most won't raise it enough to make it worth your money. remember that if it says it'll raise it by 5 points, it's not 87 up to 92, it's 87 to 87.5 and that's a maybe.
    just don't run the engine wot and take it a little easier on it. the computer and sensors will do the rest.
    '06 Supra Launch 20SSV-gone but never forgotten

  10. #10
    Join Date
    Jun 2012
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    Portland Oregon
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    805

    Default octane question

    Quote Originally Posted by LopinLH View Post
    Hey Jake what octane does your engine call for? What booster do you use? I am hoping to find some higher octane on the water but I picked up a couple bottles of Lucas Oil Booster in case....

    -Luke
    The Supra gets 87 and nothing else.

    The 6.0 ilmor in the MC gets Torco Accelerator which I believe is good for 20 points so would raise it to 89.

    What these guys are saying is true about the knock sensor, it will protect the engine and you can run 87. But for better performance run 93. That's exactly what the ilmor manual says.
    -Jake

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