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  1. #1
    Join Date
    Jan 2005
    Posts
    20

    Default Any modifications to Indmar engines to increase HP/Fuel effi

    another dumb question.... I'm an incessant tinkerer and cannot leave stock alone.

    My boat is a 2004 with the 320 HP Throttle Body FI engine. I see the factory offers a 350 HP engine, which has the same displacement and compression ratio. Supra offers a 380 HP engine with the same displacement and compression ratio.

    How did they go about getting an extra sixty HP out of the engine? I know part of it is the different exhaust manifold, and the multiport FI.

    Anyway to buy an aftermarket cam and/or exhaust manifold for these engines? Is it possible to remap the FI? I can hook my computer up to my motorcycle and remap the FI no problems, using an aftermarket blackbox and software from dynojet.

    Is it possible to increase the HP and/or fuel efficiency through standard modifications?

    I've got extensive experience on both automotive and motorcycle engines. I've rebuilt both, and raced motorcycles for a number of years (Suzuki GSXR 750, Honda RC-51).

    On every vehicle I've owned I've changed the axhaust and replaced the air filter, etc, for increased HP/better gas mileage.

    I would imagine you could do the same to a boat. Can you put a lower restriction muffler or a higher output exhaust manifold? How about changing the fuel injection mapping, or a different air filter.

    I know I'm ignorant about boats, so please be somewhat gentle. Yes, I'm aware of the impact it might have on my warranty.

    thanks,
    john

  2. #2
    Join Date
    Jun 2003
    Location
    Louisville
    Posts
    68

    Default Replying to Topic 'Any modifications to Indmar engines to in

    It wouldn't amount to much more than a few HP, but K&N does make high-flow marine flame arresters.

    http://www.knfilters.com/marine/flamearrester.htm
    2006 Outback V

  3. #3
    Join Date
    Jun 2019
    Posts
    18

    Default

    Quote Originally Posted by husky fan View Post
    another dumb question.... I'm an incessant tinkerer and cannot leave stock alone.



    Is it possible to increase the HP and/or fuel efficiency through standard modifications?

    thanks,
    john
    no-one has answered this: I would like to know as well.. for for bringing this from the dead!

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