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Thread: WOT Speed Density Tuning - Steady AFR Help

  1. #1
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    Exclamation WOT Speed Density Tuning - Steady AFR Help

    Hello. I am going to try to make this as brief as possible. I am currently trying to dial in my WOT AFR to match my commanded. I set my desired AFR in the PE table and I am using the VE table to make my adjustments to match my commanded AFR. I am self taught and fairly new. I have read every guide, thoroughly studied "The Tuning School" courses, but excuse me as I am still green. As you can see by my attached log I am unable to get a steady AFR across the board. I can not seem to accurately target my commanded AFR of 12.56 and after many, many adjustments I can only seem get my AFR to ballpark in the "12s" with a lot of fluctuation. I feel as though my method of hand tuning numbers in the VE is not allowing for a steady transitions. I will see AFRs as rich as 12.0 and as lean as 12.8 all within the same cell as it rapid fluctuates which makes it very hard to know whether to add or remove fuel. I am logging AFR Error % but I do not feel like multiplying by those large numbers is allowing me to "fine tune". The car runs decent with the fuel "somewhere in the 12s" but I know I am leaving a lot on the table by not being able to get this steady. I am also rather unfamiliar with using the smoothing and interpolate features and not sure if this is causing my rapid fluctuation in AFR. Any guidance would be great to allow me to achieve a more steady, honed in AFR. Thanks !


    Side Question: How many decimals are needed to be shown/adjusted on the VE table numbers for proper resolution? I was running whole numbers (125,126,127 etc) and feel like I am not able to get the proper resolution for a given cell. Thanks

    Note: Attached are my most recent WOT log file and my current tune.
    Attached Files Attached Files
    Last edited by Rml6636; 01-10-2019 at 05:45 PM.

  2. #2
    Tuning Addict 5FDP's Avatar
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    What's the setup you are dealing with here?

    Like engine mods, camshaft, injectors, fuel pressure etc etc. It can help give a better idea if these things happening are in part because of the specific parts used. How far back in the wideband from the manifolds??

    I can't view the tune at this moment but if you are using numbers up in the 120's in the VE on a NA setup, something seems off with how you have the tune setup.


    You can use the paste special functions to mulitply % by half so the changes aren't as big. Then just smooth the entire table or a section if you wish. You for sure do not want it jumping by 5 or 7 from cell to cell. Should be very smooth and be 1's or 2's for the most part.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  3. #3
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    Quote Originally Posted by 5FDP View Post
    What's the setup you are dealing with here?

    Like engine mods, camshaft, injectors, fuel pressure etc etc. It can help give a better idea if these things happening are in part because of the specific parts used. How far back in the wideband from the manifolds??

    I can't view the tune at this moment but if you are using numbers up in the 120's in the VE on a NA setup, something seems off with how you have the tune setup..
    Great questions. I had another experienced tuner tell me this as well as far as my VE numbers for an NA car. To give some history, I had this car tuned by a reputable shop two years prior. After more modifications I took over tuning myself. Instead of starting from scratch with this vehicle I chose to use the previous tune as a baseline to modify because the modifications were minimal (intake & throttle body, auto trans) and I had what I thought was a good tune to start with. Attached is the original tune before I began modifying it, done by the original shop. The upper end of the VE does include numbers in the 120's so I think whatever was "off" has been off from the start. This would not be something I would have known or caught had it not been for a set of experienced eyes.

    What I am viewing that is alarming is the actual AFR pid from my wideband. I compare that to the commanded AFR PID and I see how great the difference is. I am in the 12s for most of the pull but I do not have control over where in the 12s I am. I can command 12.56 but no matter how many AFR error adjustments I apply the actual AFR pid always displays somewhere in the range of 12.0-12.8 in rapid fluctuation all within the same cell. Am I over analyzing this? How do I gain a tighter control of my AFR in the 12s. Thanks!

    The setup is

    LC-2 Wideband is in collector of bank 1 manifold
    0411 PCM
    GEN III SBE 6.0
    Stock 243
    Fast 102/92
    Bolt Ons
    GM 3.8L Supercharged 3.8 Injectors 44lb @58psi
    I do not have cam specs off hand I can get within 24hr

    446rwhp/427tq mild build
    Attached Files Attached Files

  4. #4
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    To clarify what I am seeing on my AFR Error % Graph for my VE is this. I can achieve -1% across the board on my WOT pull, but my WIDEBAND AFR PID was wacky and did not match, also my visual display (read from analog signal from wideband) never matched my commanded AFR. If my commanded AFR was 12.56 , my wideband display may read between 11.9-12.2 , and the wideband afr PID may read between 12.0-12.8. With these conflicting numbers I never knew when I had actually achieved my target. Do you just stop when you reach +/- 1% on your error %?

    -Ryan

  5. #5
    Senior Tuner SultanHassanMasTuning's Avatar
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    2019-2-wot-inter-last3rows MAS.hpt

    personally when i tune VE i dont have PE setup as i ignore it, i treat the PCM like a standalone.

    looking at your VE your injector data is not right if your push 125VE on NA car
    E-tuning/remote Tuning Sultan@mastuning.net Follow @MASTUNING Contact/Whatsapp +966555366161
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  6. #6
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    low octane table has has more timing, it should be less, took a quick look scanner does not have sufficient data to tell much need injetor data if fuel is stable probably sensor issue if its bouncing around it can be more stable some variation with still happen though. set up your scanner first there are some great videos out there you need you eq er graph to work. also add commanded afr to graph so you can compare on graph. pretty busy or i would help more