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Thread: Tuning Notes by WeathermanShawn

  1. #91
    R.I.P Shawn, 1956-2011 WeathermanShawn's Avatar
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    Latest Update..

    ..WeathermanShawn..
    Last edited by WeathermanShawn; February 13th, 2010 at 11:15 AM.
    2002 Black Camaro Z-28 M6 Hardtop 11.0:1CR 425HP/410TQ SAE (400TQ@3500RPM)
    200cc Heads, 228/232 110+2 Cam, 1 3/4" LT's w/catts, GMMG, Koni Shocks, Hotchkis Springs, 35/21 Sways, 17" ZR1's, 3.90 Gears Roadrunner PCM LM-2 Serial Wideband
    EFILive Closed-Loop MAF/SD Hybrid Tune..


  2. #92
    Lifetime Member Steve Bryant's Avatar
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    Shawn,
    You've done a really good job with this tutorial. Few people can imagine just how much hard work and research goes into something like this. However, you will have learned a great deal in the end too.

    I can't comment as to its accuracy, but I'm willing to try it for myself. Thanks so much for all your efforts!

    Steve

  3. #93
    R.I.P Shawn, 1956-2011 WeathermanShawn's Avatar
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    Thanks Steve..

    Accuracy-wise, I think some of the lower RPM/MAP areas (low MAF Flow) tend to be less accurate. WOT, PE with MAF can have some scatter also. I have learned tuning is still a rather complicated procedure. To some extent you can simplify..but the complexity is an inherent part of tuning.
    Last edited by WeathermanShawn; February 9th, 2010 at 09:19 AM. Reason: Redundant..
    2002 Black Camaro Z-28 M6 Hardtop 11.0:1CR 425HP/410TQ SAE (400TQ@3500RPM)
    200cc Heads, 228/232 110+2 Cam, 1 3/4" LT's w/catts, GMMG, Koni Shocks, Hotchkis Springs, 35/21 Sways, 17" ZR1's, 3.90 Gears Roadrunner PCM LM-2 Serial Wideband
    EFILive Closed-Loop MAF/SD Hybrid Tune..


  4. #94
    Senior Member acomp917's Avatar
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    Shawn,

    Good job on the pub.

    OK!, at $20 an hour and 100 hours.............. are you willing to work for less?

    I'm going to use your system for my very first attempt at tuning. I've had a productive day and will be tuning the .tun file as soon as I get a stable 01 or 02 tune to run on my 2000.

    Thanks,
    S

  5. #95
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    Perhaps I have missed something along the way, so bear with me.

    If this is being billed as a way for beginners to start down the tuning path, and you're assuming the engine has been modified to some degree, how can avoid doing a MAF calibration if you're going to be using it as your basis for calculating VE?

  6. #96
    R.I.P Shawn, 1956-2011 WeathermanShawn's Avatar
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    No, it is my own personal tuning notes. Having started tuning about 1 1/2 years ago, I felt that tuning the VE Table (SD), the MAF (AFR), then Trims was a big chase if you were going back to MAF Closed-Loop. It is a technique of constructing a VE Table where dynamic and cylinder airflow match (MAF +/- LTFT's). The MAF Calibration is appling LTFT's to maintain stoich in non-PE mode, and have commanded AFR match your wideband AFR both at stoich and WOT/PE.

    The technique allows VE, MAF, and Trims to be simultaneously tuned. It is accurate and does work. It is best to try whatever tuning method you like..log..and share. Every 2-3 months I review my logs and tune and if something does not work the way I want it..I change it.
    Last edited by WeathermanShawn; February 9th, 2010 at 09:19 AM. Reason: Redundant..
    2002 Black Camaro Z-28 M6 Hardtop 11.0:1CR 425HP/410TQ SAE (400TQ@3500RPM)
    200cc Heads, 228/232 110+2 Cam, 1 3/4" LT's w/catts, GMMG, Koni Shocks, Hotchkis Springs, 35/21 Sways, 17" ZR1's, 3.90 Gears Roadrunner PCM LM-2 Serial Wideband
    EFILive Closed-Loop MAF/SD Hybrid Tune..


  7. #97
    Senior Member acomp917's Avatar
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    Shawn,

    I appreciate your efforts and plan to use your system approach as my first effort to tune with EFI LIVE. I like the method of using a complete "system" in an effort to simplify as apposed to hashing separate efforts. It is worth a try.

    I would now like to see if you understand the difference between SD and MAF.

    SD- (BASICS) The system knows through air density parameters(map) what the air density is(a few advanced parameters- IAT, (sometimes manifold and combustion temp). The system must know the displacement of pump(per revolution). The system must know the RPMspeed. Basically the system calculates: how many breaths(rpm), how big they are(displacement), and how much oxygen is in each breath(map). This system is good for transition. I takes into consideration how much air is actually entering the engine (even a good amount of manifold emptying and stacking(during transition).

    MAF- (BASICS) This system simply measures the amount of air entering the engine by calculating the amount of current it takes to maintain a given temperature in a heating element. The colder the air(at a given volume)... the more current, thus must be more air. The more air(at a given temp)... the more current, thus must be more air. Any combination of the above is still relevant. I just chose to maintain one constant in order to simplify the explanation.

    NOW, for a LITTLE of the tricky stuff. (WITHOUT O2Sensors) The SD system air flow (calc) is solely dependent on the VE table in order to know how much air is actually filling the cylinder(because of cam dynamics and other influences) at a given RPM and MAP reading. Thus, without an accurate VE table the PCM CANNOT know what fuel mass to apply(without O2 feedback and AFR table(or equivalent)). That is why ANY change in engine dynamics require a SD system to be re-tuned.

    A (properly calibrated) MAF system knows how much air is actually entering the engine. That is exactly it's purpose. (AGAIN) It's only drawback is that it does not understand instantaneous changes in (downstream) absolute pressure changes.

    Final note, Take a look into alphaN systems(crude) and TauX (based on manifold wetting principles due to transitional pressure change(pressure of vaporization)). These are extreme ends of the types of system that are out there.

    This is my understanding. Any criticism is welcome,
    S
    Last edited by acomp917; February 7th, 2010 at 06:38 PM. Reason: edit: Tau

  8. #98
    Senior Member acomp917's Avatar
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    Separate thought,

    What does the GM system use for acceleration enrichment? I surely hope it is not an over rich VE then transition back to MAF. If that is the case, God help us. I know NO way to balance(tune) a transition/overfuel/transition back to required fuel situation. Without a rate of change table(easy to understand)ie. TPS/MAP(Tau, best).

    Transition being from one table to another one.

    Please, someone tell me there is an acceleration enrichment in there somewhere!!!


    S

  9. #99
    R.I.P Shawn, 1956-2011 WeathermanShawn's Avatar
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    Acomp917:

    Thats a good description of the SD/MAF hybrid system.

    When logging I like to always log both GM.CYLAIR.DMA (MAF) and GM.DYNCYLAIR.DMA (Speed density) Airflow in units of g/cyl. After your log you can alway lay them out on a Map using RPM/MAP as axis. 99% of the time, both are within ~5% of each other (on my tune).

    It is good practice to participate in the actual logging process. It really is a good learning process. There are a few members on this board that log daily, and some that utilize CLSD quite successfully. It is a good way to apply theory into practical solutions.
    Last edited by WeathermanShawn; February 9th, 2010 at 09:20 AM. Reason: Redundant..
    2002 Black Camaro Z-28 M6 Hardtop 11.0:1CR 425HP/410TQ SAE (400TQ@3500RPM)
    200cc Heads, 228/232 110+2 Cam, 1 3/4" LT's w/catts, GMMG, Koni Shocks, Hotchkis Springs, 35/21 Sways, 17" ZR1's, 3.90 Gears Roadrunner PCM LM-2 Serial Wideband
    EFILive Closed-Loop MAF/SD Hybrid Tune..


  10. #100
    Senior Member acomp917's Avatar
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    Shawn,

    That info about logging both measured and theoretical air flow is good for me. I will use it.

    The explanation of SD/MAF was not meant to represent a hybrid system. It was mean to show both methods of calculating air mass. Along with fuel mass calculations(with/without feedback(O2)) They will each operate independently and each will control an engine well. Many aftermarket systems use one or the other(mostly SD).

    I will be posting the actual tuning methods... when I get there. I full flashed a 2002 tune into my 2000 silverado and now the battery (alternator) picture flashes on the dash lcd display. I'm not the first to have this problem. The original thread just stops... no conclusion. I wish people would understand the forum is about helping others and without conclusion, others are not helped.

    I will try to repay the help I receive when I have the ability.

    S

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