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Thread: Air Fuel Ratio and Transient Fueling parameters

  1. #1
    HPT Employee Eric@HPTuners's Avatar
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    Air Fuel Ratio and Transient Fueling parameters

    The highly requested stoich air/fuel ratio parameter has been added as well as 6 transient fuel tables. I have added it to a handful of Mustangs, and will have it in all Mustangs by the end of the week. Update to the latest 2.24 release to gain access.



    Eric Brooks
    HP Tuners, LLC

  2. #2
    Tuner Blown383's Avatar
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    Thank you so much Eric! Add FPAF0A3 next please! Haha jk. Good work! Just a quick question, if the car is rich on tip-out, do you decrease the values in decel?
    2007 Ford Mustang GT/CS: RGR 322 3v - JPC Intake - Vortech YSi-B - Magnum T56 XL - Built 8.8 - Full Suspension
    2008 Ford Shelby GT500: VMP Gen 2 - ATI 15% - SCJ TB - Full Bassani Exhaust - Full Suspension - Upper Pulley - Meth Injection - JLT 127mm

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    HPT Employee Eric@HPTuners's Avatar
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    Quote Originally Posted by Blown383 View Post
    Thank you so much Eric! Add FPAF0A3 next please! Haha jk. Good work! Just a quick question, if the car is rich on tip-out, do you decrease the values in decel?
    Correct, and I will have it added in tomorrow most likely.
    Eric Brooks
    HP Tuners, LLC

  4. #4
    Tuner in Training
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    The Day has come! Thank you Eric.

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    HPT Employee Eric@HPTuners's Avatar
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    Quote Originally Posted by svtadam27 View Post
    The Day has come! Thank you Eric.
    You are most welcome!
    Eric Brooks
    HP Tuners, LLC

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    HPT Employee Eric@HPTuners's Avatar
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    Quote Originally Posted by svtadam27 View Post
    The Day has come! Thank you Eric.
    Just finished FPAF0, so download the latest 2.24 release and you should see the new stuff.
    Eric Brooks
    HP Tuners, LLC

  7. #7
    Tuner Blown383's Avatar
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    Thank you so much Eric. Car is running better than ever.
    2007 Ford Mustang GT/CS: RGR 322 3v - JPC Intake - Vortech YSi-B - Magnum T56 XL - Built 8.8 - Full Suspension
    2008 Ford Shelby GT500: VMP Gen 2 - ATI 15% - SCJ TB - Full Bassani Exhaust - Full Suspension - Upper Pulley - Meth Injection - JLT 127mm

  8. #8
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    thanks god and hptuners i always told support to add transient fueling very very happy for blown engines


    only please datalog speed and need more pids

  9. #9
    HPT Employee Eric@HPTuners's Avatar
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    Quote Originally Posted by witchertorque View Post
    thanks god and hptuners i always told support to add transient fueling very very happy for blown engines


    only please datalog speed and need more pids
    High speed logging and more parameters to log is my #1 priority.

  10. #10
    Tuner Blown383's Avatar
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    Quote Originally Posted by Eric@HPTuners View Post
    Just finished FPAF0, so download the latest 2.24 release and you should see the new stuff.
    Hey Eric, Acceleration > Gain at Startup RPM Y-axis doesn't show the points or is editable. Also can you increase the MAP X-Axis limits from 31.875 to something like 64 or 128 under Transient Fuel. Inferred MAP on my car is maxing out this table. I suspect that could be an issue on high HP blower cars. Thanks!
    2007 Ford Mustang GT/CS: RGR 322 3v - JPC Intake - Vortech YSi-B - Magnum T56 XL - Built 8.8 - Full Suspension
    2008 Ford Shelby GT500: VMP Gen 2 - ATI 15% - SCJ TB - Full Bassani Exhaust - Full Suspension - Upper Pulley - Meth Injection - JLT 127mm

  11. #11
    HPT Employee Eric@HPTuners's Avatar
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    Quote Originally Posted by Blown383 View Post
    Hey Eric, Acceleration > Gain at Startup RPM Y-axis doesn't show the points or is editable. Also can you increase the MAP X-Axis limits from 31.875 to something like 64 or 128 under Transient Fuel. Inferred MAP on my car is maxing out this table. I suspect that could be an issue on high HP blower cars. Thanks!
    I fixed the Y-axis so it is now editable, and changed the max value to 64. Grab the latest 2.24 tomorrow.
    Eric Brooks
    HP Tuners, LLC

  12. #12
    Senior Tuner CCS86's Avatar
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    Eric, can you offer any insight on how these accel/decel transient fuel gain are applied?

    Are they adders/subtractors?

    Does manifold volume impact their application?

    Do they control commanded equivalence, or are they actually modifying injected fuel mass to account for transient effects like evaporation rate?
    Last edited by CCS86; 04-12-2018 at 05:56 PM.

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    i am interested too as to exactly what these tables do.

    i feel like that are modifiers to the rate of enrichment for CL accel outside of WOT

  14. #14
    Senior Tuner veeefour's Avatar
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    Just IMHO:

    You have 2 parameters that controls the Transient. Intake manifold does not affect the Transient that much to be worried. Transient is more for engine and how good or bad the engine's VE is.

    You have a GAIN and CONSTANT for deccel and accel. You also have those for startup - startup tables will be used for specified amount of time(250 seconds mostly) and then it will switch to normal tables.

    Transient is TIME required to fill the cylinders with AF mixture since it's port injected. Direct injected engines use the transient tables as well but I'm not even sure why - they are tuned differently tho.

    Time constant is your amount - you may treat is as SECONDS.

    Gain is your amplification/multiplication - you may treat it as PULSE just like with injectors.

    Increase gain - more fuel will be added.

    Increase time and it will stay being added longer.

    I don't think you should really tune Transient in a stock engine - you may have to with build engine or with some serious changes to intake system.
    I really think most "tips" in fueling are caused by MAF or Speed Density - I'd would rather tune the Transport Delay before touching Transient tables.
    Last edited by veeefour; 04-23-2018 at 08:29 AM.

  15. #15
    Senior Tuner CCS86's Avatar
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    Quote Originally Posted by veeefour View Post
    Just IMHO:

    You have 2 parameters that controls the Transient. Intake manifold does not affect the Transient that much to be worried. Transient is more for engine and how good or bad the engine's VE is.

    You have a GAIN and CONSTANT for deccel and accel. You also have those for startup - startup tables will be used for specified amount of time(250 seconds mostly) and then it will switch to normal tables.

    Transient is TIME required to fill the cylinders with AF mixture since it's port injected. Direct injected engines use the transient tables as well but I'm not even sure why - they are tuned differently tho.

    Time constant is your amount - you may treat is as SECONDS.

    Gain is your amplification/multiplication - you may treat it as PULSE just like with injectors.

    Increase gain - more fuel will be added.

    Increase time and it will stay being added longer.

    I don't think you should really tune Transient is a stock engine - you may have to with build engine or with some serious changes to intake system.
    I really think most "tips" in fueling are caused by MAF or Speed Density - I'd would rather tune the Transport Delay before touching Transient tables.


    What is your approach to tuning transport delay? Maybe you could add your 0.02 here: https://forum.hptuners.com/showthrea...-Time-Constant


    From my testing, I have seen definite changes in the short tip-in / tip-out fueling errors when changing Manifold Volume and the Transient Gain tables. My biggest struggle at the moment, are long, slow swings in the STFTs, when everything else appears to be very stable:

    FT Swing at Stop.png
    R6w-idle-FT-swing.hpl

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  17. #17
    Senior Tuner CCS86's Avatar
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    Yes, I am logging commanded vs measured.

    My current technique is to find steady periods within a certain RPM/load combination, then average the time distance shown here over a number of O2 cycles and use that to feed back into the transport delay tables. Are you doing something different?

    Transport-delay.png

  18. #18
    Senior Tuner veeefour's Avatar
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    Nope, exactly this way. Just make sure to filter some random hits.

  19. #19
    Senior Tuner CCS86's Avatar
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    I'm surprised it is so far off from the factory values. My exhaust is stock between the head and O2 sensors.


    Any thoughts on that log I posted? Those slow transient STFT swings are refusing to die.

  20. #20
    Senior Tuner veeefour's Avatar
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    Have you tried switching the SD off?