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  1. #1

    Circumventing the rev limiter?

    Ok, I have a 2005 F12X, and it gps's at 60.7 on average... I have been reading all the info posted on here of everyone trying to circumvent the rev limiter, and allowing the engine to turn up the rpm's to get it in the 70mph range.. first of all, mine is totally stock, and has about 51 hrs on it, and never a problem. Question is, I also have an 04 F12 engine collecting dust, including the ecm, and I was wondering if I swapped all the sensors, crank, cam, and whatever else is different, and swapped the ecm, would it allow the engine to turn beyond the 6400 rev limit? I tried swapping the ecm from the non turbo unit, and it ran great, but only at idle, and slightly over... when I cranked the throttle, it totally bogged down, and wouldnt get out of its own way. I feel there has to be a way to allow the engine to turn at least in the 7k range, since my old F12 did just that with ease... Any info reguarding this experiment would greatly be appreciated.


  2. #2
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    Simply put you need more HP to go 70. The RPM limit removed does not add HP.

    The F12 uses a much lower pitch and requires less power to turn. Even if you put a F12 prop on an F12x with the RPM limit removed you will not go fast, As you did not add HP by just reducing the load by the pitch change.


    Shawn

  3. #3
    Ok, that makes since, and I didnt realize that at wot, I wasnt hitting the limiter, just close. The thing I dont understand, is why I have an 18ft bass boat with a 135hp outboard, that will walk away from my ski with ease top end... and with less hp. Is the jet drive in my ski that un-officient compared to the boat prop??? I mean, my boat is about 2600 lbs, and will do 71 mph all day long, and I have an 800 lb ski with more hp, that will only do 60? Maybe I need to concentrate my energy on a more efficient pump assembly, and making it 'more slippery' with the water.... serious power and effiency is being lost somewheres, and I am gonna find it!

  4. #4
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    Yes, That is correct, work on the Hull and its components more till you hit the rev limit, Then worry about that.

    Jet pumps are a very inefficient way of transferring energy.

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