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  1. #1

    Default Supra 2015 SA400

    Hi All,
    My Indmar 400 tops out at 4000rpm. All the specs Iíve read mentions maximum torque is at 5,400rpm.
    Iíve only owned the boat for 12month and I know wake boats arnít designed for speed, but Iím wondering if Iím missing out on power or possibly throttle cable adjustment to allow for WOT.

    Any thoughts or experiences??

    Thanks


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  2. #2
    Join Date
    Aug 2011
    Location
    Commerce Lake, MI
    Posts
    1,562

    Default

    Quote Originally Posted by mor3naz0 View Post
    Hi All,
    My Indmar 400 tops out at 4000rpm. All the specs Iíve read mentions maximum torque is at 5,400rpm.
    Iíve only owned the boat for 12month and I know wake boats arnít designed for speed, but Iím wondering if Iím missing out on power or possibly throttle cable adjustment to allow for WOT.

    Any thoughts or experiences??

    Thanks


    Sent from my iPhone using Tapatalk
    4000rpm exactly, or somewhere around there?

    If so it could be the ECM is limiting the engine to 4000rpm due to an out of spec condition it is seeing. Do you have a check engine light?

    If itís around that and not exactly that speed, you might have a prop on with too much pitch. What prop is on there? Get the part number and/or specs of the back of the hub.


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    2017 Moomba Craz

  3. #3
    Join Date
    Oct 2018
    Location
    Hockley, Tx
    Posts
    206

    Default

    Quote Originally Posted by mor3naz0 View Post
    Hi All,
    My Indmar 400 tops out at 4000rpm. All the specs I’ve read mentions maximum torque is at 5,400rpm.
    I’ve only owned the boat for 12month and I know wake boats arn’t designed for speed, but I’m wondering if I’m missing out on power or possibly throttle cable adjustment to allow for WOT.

    Any thoughts or experiences??

    Thanks


    Sent from my iPhone using Tapatalk
    I believe that the Maximum Torque with the Indmar Raptor 400 is achieved between 2,500 & 3,500 RPM. The WOT RPM is supposed to be between 5,000 & 5,400 RPM. I have to agree with Stazi if it is holding exactly 4,000 RPM might be an engine problem but other wise and maybe more likely it is a proping issue.
    2019 Makai (On Order)

  4. #4

    Default

    Thanks boys.
    Iíll check the RPM plus prop over the weekend and reply back.

    I am a little confused though. If it just a ďpropĒ specification and not the ECU telling it to stop at 4K why wouldnít the engine rev still rev to 5400?

    Does the prop create so much resistance/drag that the engine canít reach that RPM?

    I guess Iím drawing similarities to a car with different sized wheels. Engine still reaches same RPM but different speeds for different sized wheels.



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  5. #5
    Join Date
    Aug 2011
    Location
    Commerce Lake, MI
    Posts
    1,562

    Default

    You canít directly compare it to a car as the load on the car is not constant, like it is on a boat. You cannot coast in a boat there is always load on the engine when moving forward. Think of it more like Top Speed in a car. So depending on what gear you are in you will reach a different top speed. In a boat the pitch of the prop dictates how much the engine can rev depending on the load on the engine which is directly related to the pitch of the prop.

    If you had a prop with no pitch so it was basically a disk, the engine would rip all the way to redline and bounce off the rev limiter, but you wouldnít move. Now think about it if you had a prop with a pitch that was letís say 45į, so itís pretty aggressive. The power of the engine can only turn the prop so fast and it will not reach redline as it will never be able to generate enough power to get there.


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    2017 Moomba Craz

  6. #6
    Join Date
    Jan 2008
    Location
    Tallahassee, FL
    Posts
    14,029

    Default

    That is a dang good explanation right there. You should also mention the elevation where you are running as it can affect things as well.
    My Mom said I'm not allowed to get wet!
    2008 LSV (sold)
    2000 Outback LS (sold)
    LLTR!!!!!!!!



  7. #7
    Join Date
    May 2018
    Posts
    616

    Default

    Also how much ballast is in the boat.


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  8. #8
    Join Date
    Oct 2018
    Location
    Hockley, Tx
    Posts
    206

    Thumbs up

    Quote Originally Posted by Stazi View Post
    You can’t directly compare it to a car as the load on the car is not constant, like it is on a boat. You cannot coast in a boat there is always load on the engine when moving forward. Think of it more like Top Speed in a car. So depending on what gear you are in you will reach a different top speed. In a boat the pitch of the prop dictates how much the engine can rev depending on the load on the engine which is directly related to the pitch of the prop.

    If you had a prop with no pitch so it was basically a disk, the engine would rip all the way to redline and bounce off the rev limiter, but you wouldn¬ít move. Now think about it if you had a prop with a pitch that was let¬ís say 45¬į, so it¬ís pretty aggressive. The power of the engine can only turn the prop so fast and it will not reach redline as it will never be able to generate enough power to get there.


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    Good explanation right there ^^

    Props can affect a lot about how a boat acts and performs.
    2019 Makai (On Order)

  9. #9

    Default

    Quote Originally Posted by Stazi View Post
    4000rpm exactly, or somewhere around there?

    If so it could be the ECM is limiting the engine to 4000rpm due to an out of spec condition it is seeing. Do you have a check engine light?

    If itís around that and not exactly that speed, you might have a prop on with too much pitch. What prop is on there? Get the part number and/or specs of the back of the hub.


    Sent from my iPad using Tapatalk
    Hi,
    Have only just gotten time to get to the shed where the boat is kept. Iíve taken some pics of the prop, itís a 1235.
    What type of prop is this?



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  10. #10
    Join Date
    Aug 2011
    Location
    Commerce Lake, MI
    Posts
    1,562

    Default

    Thatís the standard wakeboard prop. Your boat should not ever have an issue with it. Sounds like something else in the engine management system is limiting the max rpms.


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    2017 Moomba Craz

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