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Rev limiter questions

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  • Rev limiter questions

    Does my 04 larson 230, which is equipped with a 5.0 GXI Volvo penta setup have one?? How do I know when it kicks in?

    Background; I have been working with a prop manufacturer to get me a custom SS 4 blade lab finished prop. In my latest round of testing, I was attempting to see how many RPM's the prop would allow me to run. WOT is listed as 4800-5000. At 5300 I noticed a slight cutout in the engine. Was this my rev limiter? It coincidentally would not go any faster. In my first round of testing, I backed out of the throttle at what I thought was 5400.

    I thought all newer boats were equipped with rev limiters. Is that limit 300 over max WOT???

    Confused?!?!
    "Everyone's an a** except for me and you... and I'm not so sure about you."


    2004 Larson 230LXI W/VP 5.0 AKA [COLOR=#00ff00]Mr Toads Wild Ride
    2003 Dodge ram 2500 W/5.9 Diesel-6spd manual


  • #2
    Re: Rev limiter questions

    WOT and your rev limiter are two different things, WOT is with a load (prop) and the range at which your motor will is most efficient. you want the prop to allow your rpms to fall into this range when the throttle is wide open. the rev limiter is there to keep you from blowing your motor up and protect the accessories such as alternator, power steering, etc.

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    • #3
      Re: Rev limiter questions

      I'm betting you do have a rev limiter, and that's likely what was causing the slight miss at 5300. Your WOT range of 4800-5000 rpm is your target, not a hard rev limit. As you've seen, you can exceed this range if you under prop, or shove the throttle with the drive disengaged, etc... , the rev limiter kick in to keep the engine from running over it's limit. Not sure how far over the upper end of the WOT range is your red line. Now that you mention it, I don't know what my boat's red line is either. Also, your boat's tachometer could be off by a margin so the 5300 or 5400 your tach was indicating might be off.

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      • #4
        Re: Rev limiter questions

        Your rev limiter is preset at 4950 rpm. Your tach is off by 250 rpm at 4950 it will shut off the fuel supply creating a lean burn so do not spend much time there. Vortec engine's run out of air at that point..(head cam design) so prop to 48-49...It sounds like a minute miss at wot.
        Stickly a opinion your milage may vary.

        Speed is how fast you hit the wall
        Torque is how far you move the wall"

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        • #5
          Re: Rev limiter questions

          The rev limiter is an internal part of the ECM, it's set to stop fuel injectors from working until the rpm is at or below the set limit. It's normally set to 200 rpm over the max rpm of your engine range, in this case 4600 to 5000 rpm. Which would make your rev limiter starting at 5200 rpm.
          Don S.

          sigpic

          Please, no PM's (Private Messages) regarding boat/engine problems.
          That is what the forums are for.
          Only forum/moderator issues will be answered in PM's.

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          • #6
            Re: Rev limiter questions

            Good thing all posts are in agreement as always . . .

            TG,

            Where'd you find 4950? Seems odd to be lower than recommended WOT range
            Torque gets you there. Horsepower gets you there in time for dinner.

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            • #7
              Re: Rev limiter questions

              Originally posted by QC View Post
              Good thing all posts are in agreement as always . . .

              TG,

              Where'd you find 4950? Seems odd to be lower than recommended WOT range

              My laptop of course uisng a mefiburn program....But he does have a v8 and most importantly the Oracle has spoken....And so it is.....Hey 50 isnt bad its a monday geesh...
              Stickly a opinion your milage may vary.

              Speed is how fast you hit the wall
              Torque is how far you move the wall"

              Comment



              • #8
                Sign up today
                Re: Rev limiter questions

                So.....I understand and agree that the Tach could be/probably is not completely accurate. 5200 sounds correct since I was reading 5300+ or - when I was feeling the 'miss'. Okay, so I feel reasonably sure I understand this.

                Talked to my boat mechanic today, and he will run a tach check on it when we winterize(Yeah I said it!!!! suck suck suck) in a few weeks.

                My plan is to prop to 4800, prop guy assured me he could take all factors and plug them into his 'program' and create the perfect prop. So far 2 runs, and were still overpropped. On the plus side, I really like the feel of the SS prop. I'm sending it back to be re-worked, and hopefully we get it closer.
                "Everyone's an a** except for me and you... and I'm not so sure about you."


                2004 Larson 230LXI W/VP 5.0 AKA [COLOR=#00ff00]Mr Toads Wild Ride
                2003 Dodge ram 2500 W/5.9 Diesel-6spd manual

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