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Thread: Apply Time Offset to Wideband Input?

  1. #1

    Apply Time Offset to Wideband Input?

    While working to tune my transient fueling, I've always had to account for a delay of about 100ms in my wideband signal. Is there any way to 'advance' an analog input's position in time in a log relative to the other PIDs to make it align with the actual operation? For example, I would like to shift my wideband input's readings 100ms earlier in time to account for the delay. I tried exporting the scan to .csv, applying this advance, resaving as .csv, and opening it as a log, but the importing dialog box never goes away and the log doesn't open. A much easier way would be to be able to apply a time shift to the analog input's playback readings in the final log, even if it isn't accounted for in the realtime streaming. I'm not sure how difficult this would be, but it would be of huge benefit in my opinion.

  2. #2
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    Short of doing it manually, no, not really. I asked the same a while back and dr.mike (he does a lot of testing on WB's) basically said the time it took to get from point A to point B was different depending on how far it had to go, so a single offset value would not really work all that well

    I'm looking into faster WB's to see how they do. The new AEM's are supposed to be in the 20 millisecond range

    What WB are you using now?
    Post a log and tune if you want help

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  3. #3
    I'm using an innovate LC-2. They say that their delay is generally under 25 ms, but the spec is for <100. I find that it's generally much closer to 100 ms than 25 ms in my use. Even if it wouldn't be perfect, it would still help if there was even a right click option in a recorded log to delay or advance the PID data in time so it would line up with things in chart view. Maybe wishful thinking, though.

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    Pretty sure I asked for that back when 2.25 was in beta but it didn't get implemented so kind of doubt it will to be honest. Here's to asking though.
    Post a log and tune if you want help

    VCM Suite V3+ GETTING STARTED THREADS / HOW TO's

    Tuner by night
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    2005 Corvette, M6
    ECS 1500 Supercharger
    AlkyControl Meth, Monster LT1-S Twin, NT05R's
    ID1000's, 220/240, .598/.598, 118 from Cam Motion

    2007 Escalade, A6
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  5. #5
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    Unfortunately, it doesn't work that way It's not that a slower WB give you the right data, delayed by some milliseconds. It's more like the data is "smeared" over a number of milliseconds. A bit like being badly out of focus. Here is an example:

    t63-plots2b.jpg

    These are the ideal response curves for WBs with varioud t63 response times, reacting to an 80ms lean spot of lambda 1.5. You can see there, that the 100ms signal is not the right 1.5 lambda lean spot, delayed by 100ms. It never even makes it to lambda 1.3, before tapering back to 1.00.

    Up to about the 20ms units, they give a pretty good representation of the actual event. Beyond that, you have to do a lot of "reading between the lines", to figure out what really happened.

    The LC-2 only updates its outputs 12 times a seconds ( every 82ms ). So, it's minimum reliable delay is 82ms. I don;t know where they get the 25ms number from. That would apply to the older LC-1 controllers, in "instant mode".

  6. #6
    Senior Tuner 10_SS's Avatar
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    Here's a perfect example of why we need time shifting at least on "averaged" data like analog inputs, or AVERAGE filters that you create.

    I simply averaged my AEM 03-0300 data just to make it look smoother... well I achieved that, but also it "shifted" all of the data out, effectively delaying it.

    Time shifting would actually be useful even though averaging the data "smears" it. Then i realized the Histograms simply average that data anyway, but it is not time shifted in any way, so it's still accurate.

    Yellow is non-averaged data.
    Red is the same data, but averaged/smoothed, therefore "time shifted"

    AEM vs Averaged WB.PNG
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  7. #7
    HP Tuners Owner Keith@HPTuners's Avatar
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    You guys ask for too much.

    Bring this up after 3.2 is released. However, I'm not sure if we'll be able to do something like .avg(200).offset(-200)... but, maybe, we could do something like .avg(100, -100)
    We got this guy Not Sure, ...

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    We gotta keep you guys busy(ier)

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    Senior Tuner 10_SS's Avatar
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    Quote Originally Posted by Keith@HPTuners View Post
    You guys ask for too much.
    on a serious note... is there any way to shorten up the lables on the Chart? Mine are starting to overlap... i thought we used to be able to call them whatever we wanted? my pic in my post above shows what im talking about...
    2010 Camaro LS3 (E38 ECU - Spark only). MS3X running complete RTT fuel control (wideband).
    Whipple 2.9L, 3.875" Pulley, kit injectors, supplied MSD Boost-A-Pump, stock pump
    LG Motorsports 1 7/8" Headers - No Cats, stock mid pipe with JBA Axle Back
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  10. #10
    Senior Tuner 10_SS's Avatar
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    More Examples. In this one, the pink line is the delay'd/ave/shifted one. Needs a bump to the left is all. Ignore the text overlapping we have no control over that anymore, for some reason it's including the entire "Unit" string for whatever reason..., and not just the Label. Can we exclude units?

    Smooth_Delay.PNG

    Smooth_Delay2.PNG

    Smooth_Delay3.PNG
    Last edited by 10_SS; 06-11-2016 at 12:39 AM.
    2010 Camaro LS3 (E38 ECU - Spark only). MS3X running complete RTT fuel control (wideband).
    Whipple 2.9L, 3.875" Pulley, kit injectors, supplied MSD Boost-A-Pump, stock pump
    LG Motorsports 1 7/8" Headers - No Cats, stock mid pipe with JBA Axle Back
    ZL1 Wheels/Tires

  11. #11
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    I don't think you can get rid of them entirely. If you really wanted to you might could do a math parameter that is just equal to AFR or whatever PID and leave the units blank on it, then use that in charts instead

  12. #12
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    I would also like to have this for reviewing logs for transient fuel tuning.

  13. #13
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    I write my own excel VBA and have do a time shift routine to match the WB results with the correct engine combustion event. You have to take into account load and RPM... it was some guesswork at first but then you can see it match pretty well when you get the parameters right. FYI the ECU has to do it for the narrow band O2 sensors too. I did learn that it doesn't matter much for WoT testing. At WoT high load, fairly high RPM the exhaust slug is moving really fast. In my case with the WB in the collector of a long tube header the computed shift was less than the sample interval, so just leave it alone.

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    I'd be interested in a copy of that spreadsheet if you would be willing to send it. Once I get my truck back up and running I plan on logging pretty much every drive to see what I can learn.

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    Quote Originally Posted by Keith@HPTuners View Post
    You guys ask for too much.

    Bring this up after 3.2 is released. However, I'm not sure if we'll be able to do something like .avg(200).offset(-200)... but, maybe, we could do something like .avg(100, -100)
    Anyway this could be put on the short list for new features?

    I think a simple time offset would be very helpful like .Offset(250) or .Offset(-250)

    Thanks,
    Branden