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Thread: Optimum idle rpm base setpoint or target idle speed

  1. #1
    Tuner in Training
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    Optimum idle rpm base setpoint or target idle speed

    Brand new user here. Is there a method for determining what is "best"?

  2. #2
    Tuning Addict 5FDP's Avatar
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    I mean sorta.

    It depends so much on what the vehicle is, what transmission it's running and other mods done to the engine like displacement, camshaft, turbo/supercharger etc etc.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
    Tuner in Training
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    Thanks for the quick response. Vehicle is an 08 Silverado 5.3 4L60e e38 ecm. Mods are K&N cold air intake and a BTR Stage 2 Truck cam thanks to a D.O.D. lifter failure. 212/218 111lsa -7 overlap.

    It will start and idle fine on the factory rpm. Low, but it holds, no surging or hunting. It does however die sometimes coming to a stop.

    I attempted to use a few recommended baselines and my situation was always worse. So I made the decision(hopefully not bad) to address one parameter at a time.

    If I go to vcm scanner and use the controls function I can manually adjust idle. Raising it increases the throttle opening, and decreases kpa. I'm assuming this is directly inverse with lowering so neither of those 2 parameters would be judges. I've attempted to great a graph and chart for desired vs actual rpm including error, but error reporting will not appear on either. Not sure what I'm missing there. Also interesting, and disappointing that I dont have a spark advance option through the controller, only retard.

  4. #4
    Tuning Addict 5FDP's Avatar
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    I would do a 650-700rpm idle with that camshaft. Aim for something like 18-20ish degrees of timing at idle.

    Make sure the over/underspeed spark correction tables aren't to wild. Keep it around +/- 8-10 degrees. Most stock tables will be like +/- 20 or more degree sometimes.

    It may need slight changes to base running airflow and for sure the MAF/VVE need to be tuned to get idle under control. If the MAF/VVE are tuned it will make fine tuning the idle that much easier.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  5. #5
    Advanced Tuner
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    Can you share the file? Do you have any logs of it when it dies/when it's idling?

  6. #6
    Tuner in Training
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    I can share logs if wanted. Im really not looking necessarily for anyone to tell me what to do necessarily. Im more interested in wanting to know how to make my own decisions, just as long as theyre intelligent ones. Im super slow with this software, borderline overwhelmed with the number of options, def overwhelmed with the lack of familiarity with the software itsself although thats becoming increasingly familiar as time passes. As i mentioned earlier ive set the idle back to stock for now and decided to tune part throttle and idle maf first, and move to VE next. Will have a wideband tomorrow evening and ill prob leave idle til last.

    I am still curious about charting rpm error though.

    5FDP, ive seen a handful of vids where gen iii trucks could raise timing from idle while logging/running via vcm scanner. Mine only allows retard, no advance feature. Is this normal? Or is there a simple method for dialing in optimal timing without having to due multiple back to back flashes? Would a vacuum increase be the only thing to look at when choosing optimal timing? Or are there other areas to keep an eye on as well?