SEST lower idle Rmp 850

Discussion in 'Engine, Fuel and Exhaust' started by wishbiker, Nov 25, 2009.

  1. wishbiker

    wishbiker Member

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    I would like to know if is bad for engine (flhrc 09) to low the idle rpm to 850?

    The local dealer think that the mini rpm is 952 and it's not possible to lowering more because it's make a problem for oil pressure and voltage.

    It's strange in fact because the mini value to the super tuner is 800 rpm:small3d031:

    If you have a idea ... Many thanks

    :FRANCE
     
  2. chester1957

    chester1957 Member

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    The dealer is right, maunual states 950 to 1050 at idle. Not sure about voltage, more about oil volume.
     
  3. wishbiker

    wishbiker Member

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    Just a small precision I talk about hot engine temp (96 degre) for 850 idle rpm
     
  4. wishbiker

    wishbiker Member

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    [​IMG]

    It's screen values to mysuper tuner
     
  5. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    With EFI, ECM to control fuel metering and ignition, probably is possible for the idle to be dropped way low, but as the dealer said, the charging system will be operating in "loss mode" (less than min. 12.6V charge voltage) with all that electronics and headlight running puts big time load on battery, which is designed for float charge, not deep discharge. And yes, oil output will be quite low, with possibly insufficient pressure to keep cooling misters and oil galleries pressurized to keep bearings and reciprocating parts from contacting with enough lubrication when starting up.

    I would not use a "chart" that tries to optimise say engine temperature & idle speed only...there are many other factors that weigh in to the dynamic performance of an engine than just a two dimensional calculation. That was the type of scenario done in the early days, and even fundamental engines 101 says there are 3 items minimum for a 3 dimensional map: air, fuel and heat...JMHO
     
    Last edited: Nov 25, 2009
  6. Hoople

    Hoople Account Removed

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    Does HD really think your head temp could go to 375 degrees F..

    You could melt solder..Wow !:p
     
  7. Hoople

    Hoople Account Removed

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    I guess it really can. Now that I think about it, I saw mine go to 309* and I was just sitting in my garage playing with the SERT on a cool summer night.
    Downtown afternoon summer traffic in Dallas Texas....O Ya!:p I am sure your gonna see some really high numbers.
     
  8. Hoople

    Hoople Account Removed

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    Yes, that is some really good info to know. I have never noticed that feature kick in so far, but I am running a pretty fat A/F ratio at idle & cruise.

    Think I may take some rosin core solder and wrap a few turns around my cylinders. If I see it when I look down, I have nothing to worry about!:p:p
    They don't call me sick puppy for nothing!
     
  9. wishbiker

    wishbiker Member

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    I modified all table (afr 13.5, IAC...) but I don't understand why SEST can change the value rpm to 800 if is bad for the engine?

    WHen the engine is hot 110°C the oil pression is to 30psi at 850 rpm is normaly good. :yeahright
     
  10. Hoople

    Hoople Account Removed

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    I would say if your positively sure your oil pressure is 30 PSI when the engine is HOT and your battery is Positively charging, you are not doing any damage or will have any problems.

    Software will always allow you extremes with any settings. Another example is cylinder timing. SERT will allow you to set your timing to 45 degrees advance for the rear cylinder while under WOT. But would you really ever want to do it.
    Don't ever think just because the software "allows" you too, you are safe. I am sure there are engines out there that have clearances which would result in much lower oil pressure than 30psi @ 800 RPM.