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  1. #11
    Join Date
    Jun 2008
    Location
    De Pere WI
    Posts
    4,170

    Default

    assuming the computer used to run these engines is similar to a car. the computer will detect the knocking/pinging and retard the timing to compensate for it. as long as it continues to detect, it'll run in a retard state and you will have some sacrifice in power. I don't think anyone will ever notice a boat running full tune and one running with the timing advance in a retard state, but as mla suggested, this will have some longterm effects on the overall wear of the rings/pistons/valves and seals. most engines today have quite a bit of "safe" room in the tune tho..


    went to 2 tuners over the years to get the old mitsu evo's tuned. it was fun to watch the pc hooked up to it real-time detect and retard the ignition when picking up on knocking/pinging. one was on the interstates out by the salt lake city airport and done while driving. tuned the last one to the brink at a shop in portland on a dyno. original baseline dyno was 330hp/310tq. when I left, it was at 363hp/362tq with no other parts swaps, just an ecu tune. shows how conservative the engine tunes can be. sure mike has even bigger gains from diesels and tuners.
    '06 Supra Launch 20SSV-gone but never forgotten

  2. #12
    Join Date
    Sep 2013
    Location
    cape cod
    Posts
    18

    Default

    Thank you for your help

  3. #13
    Join Date
    Feb 2008
    Location
    Sylvan Lake, Alberta
    Posts
    473

    Default

    I put 400 hours on my 08 XLV and ONLY ran 87 and it never gave so much as a hic up.
    Levi
    Former owner of a 08 Mobuis XLV, Cat340, 2650 Lbs.
    I miss that boat!

  4. #14
    Join Date
    Nov 2010
    Location
    Katy, TX
    Posts
    4,150

    Default Fuel For My New Mojo

    Quote Originally Posted by 501 View Post
    I put 400 hours on my 08 XLV and ONLY ran 87 and it never gave so much as a hic up.
    As mike mentioned elevation plays a big factor as well. The higher up you are the thinner the air the less compression pressure the lower the octane needed. I know in Lubbock which is about 3400 ft above sea level you can't even buy 87, their low grade is 86 because the air is thinner. They say for every 1000 ft climb in elevation your engine loses 3% of its power. I don't think 87 to 89 is a big enough difference to cause any major damage. If it requires like 110 race gas and someone was using 87 then yeah, that would be a big deal. If you use 87 and don't want to pay for 89 then fill you tank half with 87 and half with 89 and now you have 88. Compromise haha


    Sent from my iPhone
    David

    2008 Mobius LSV, Gravity III , Wake Plate, Z5, Exile SX65c's, Exile XM9s, Exile XI12D, Exile Harpoon, Exile SM600.1 , Exile Xi800.4.

  5. #15
    Join Date
    Jun 2013
    Location
    Lake Orion, MI
    Posts
    429

    Default

    A lot of higher elevation areas (like CO) start at 85 octane for regular...I always wondered why that was and never realized that may be because of the elevation lol.
    2006 Mobius LSV
    Previous ride - 2000 Supra Launch

  6. #16
    Join Date
    Jan 2008
    Location
    Tallahassee, FL
    Posts
    11,242

    Default

    Quote Originally Posted by sandm View Post
    it'll run in a retard state and you will have some sacrifice in power.
    I been running this way for years. Wonder if I should be drinking Monster or Red Bull instead of Yeungling?
    My Mom said I'm not allowed to get wet!
    2008 LSV
    2000 Outback LS (sold)
    Exile Tunes
    PWI
    LLTR!!!!!!!!



  7. #17
    Join Date
    Aug 2006
    Location
    Baton Rouge, LA / Big Bay Lake, MS
    Posts
    2,246

    Default

    i have been told dont waste money on over 89 either as it is calibrated for 89.. if you blend higher with 87 that is worthy, but dont expect any improvements by running 93.
    Long running debate on here and wakeworld about 87 v 89. Many of us have done 87 plenty with no noticeable issues.
    I ran a couple of Acura TL's that demanded 91 or higher.. was a pain but its all about the compression, computer, etc.
    I try to stick to 89 most of the time though.
    Brad

    Mississippi/Louisiana
    2011 Launch 21V
    2006 Moomba Mobius LSV sold
    2004 Outback sold

  8. #18
    Join Date
    Jan 2008
    Location
    Tallahassee, FL
    Posts
    11,242

    Default

    Funny but on my '08 I'm pretty sure my boat manual says run 89 but my Indmar manual says run 87.
    My Mom said I'm not allowed to get wet!
    2008 LSV
    2000 Outback LS (sold)
    Exile Tunes
    PWI
    LLTR!!!!!!!!



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