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Thread: Disabling PE to tune 100kPa cells

  1. #1
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    Disabling PE to tune 100kPa cells

    As per the multitude of guides I've read on tuning, I've been slowly edging the values in the "TPS Threshold for PE" tables (high and low coolant temp) up to enable tuning the VE at higher engine loads.

    However, I've just come across a couple threads on other forums of very excited people swearing this method will inevitably cause your engine to self-destruct, I assume due to detonation.
    The guides I read made clear the risk of detonation, but I have forged pistons and don't have an extreme build (est. <320hp from a 383), and I had been closely monitoring knock counts (<10 in a 25min datalogging loop), but if you guys have had bad experiences doing this way, I definitely would rather play it safe.

    Is there merit to this: should I just extrapolate to calculate my high-load VEs, or do I need to get a wideband O2 sensor to tune these areas?

    Thanks in advance.

  2. #2
    LT1 specialist steveo's Avatar
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    prolonged high rpm high load at stoich will eventually nuke your engine, the extra fuel from PE cools things off, also the more load you have, the more catastrophic the effect from momentary lean swings from the o2.

    but in the short term trying to get a stoich fuel map in a larger rehion, you'll be fine. i've done plenty of tunes like that.

  3. #3
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    Thanks!
    How do you go about disabling PE? When I set the min TPS for PE to 100, or any greater value, it changes to 99.61 (I assume floating-point rounding error combined with a XDF limit of 100% throttle), and it similarly won't let me set the minimum MAP to greater than 100 kPa.

    EDIT:
    Also, is there any other stuff like PE that has to be disabled? I noticed some "Accel Enrich" tables that seem like they could interfere?
    Last edited by 90Vette; 06-02-2017 at 07:40 AM.

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    Oh, really? How do I do that?

    And no, I just use TunerPro RT and an Excel spreadsheet I made.

    EDIT:
    Downloaded Trimalyzer and it looks head-and-shoulders above my Excel-based adjustments. Do you have any tips for using it? I've gotten to the table analysis based on my log but I'm not sure about some of the settings (i.e. geometric vs loose cell vs strict cell; min. and max. adj.) and functions.

    Also, I see Trimalyzer has the RPM bins 200 RPM wide, but my lower VE table is in increments of only 100 RPM. There must be a setting to adjust that?
    Figured this one out, this can be adjusted with the "New VE Layout" button.

    Is there a way to copy the table from Trimalyzer? Not sure I want to manually adjust every cell in my VE table; it would be nice to copy-paste Trimalyzer's percent adjustments as well as my current VE tables to Excel and then just copy-paste my resulting VE table to TunerPro.
    Ah, it appears "Modify Clipboard Data" is for this purpose.

    Do you do the entire adjustment Trimalyzer suggests, or do you temper it somehow? (E.g. by averaging the new tune with your old one, setting max adjustment to a sufficiently small value, etc.)

    I take it you filter out PE and AE records by adding a target AFR = 14.73 filter?

    Thank you so much for introducing me to this software, and sorry for the flood of questions! (Just saw you said you're the creator of Trimalyzer, very impressive!)
    Last edited by 90Vette; 06-02-2017 at 09:16 PM.

  6. #6
    LT1 specialist steveo's Avatar
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    Quote Originally Posted by 90Vette View Post
    I take it you filter out PE and AE records by adding a target AFR = 14.73 filter?
    totally depends on the capabilities of your mask. the default filters are really conservative. ideally i like to see filters like:

    - closed loop = true
    - block learn mode = true
    - accel enrichment = false
    - power enrichment = false
    - tps > 1%
    - map > 20kpa
    - coolant temp > whatever your thermostat temperature is

    some of these may be unnecessary depending on how your mask works

    Do you do the entire adjustment Trimalyzer suggests, or do you temper it somehow? (E.g. by averaging the new tune with your old one, setting max adjustment to a sufficiently small value, etc.)
    perhaps keep an incremental stack of your changes (bin 1, bin 2, bin 3, bin 4) and every time you dump the new VE table, go ahead and compare to the old bin, make sure the changes are sane.

    or look at the adjustments. if you're getting wacky trim recommendations in a particular rpm or map range, simply rework your filters to reject that data.

    Do you have any tips for using it? I've gotten to the table analysis based on my log but I'm not sure about some of the settings (i.e. geometric vs loose cell vs strict cell; min. and max. adj.) and functions.
    there are tooltips on some stuff, hover your mouse over stuff and it'll explain it a little bit, but for the most part i kind of intend people to figure it out on their own.

    strict cell is like your spreadsheet.

    loose cell allows data to cross into adjacent cells if data points are near a cell border (so if you have 100,200,300 rpm and a data point is 299rpm, it would affect both 200 and 300 rpm cells, whereas 220rpm wouldn't).

    geometric actually takes the table and skews its geometry into a square so linear math can work properly, then attempts to perform a mutant geometric distance-from-datapoint calculation to establish a dynamic relationship between a data point and a cell. so lets say you have a 200,300,400,500 rpm set and your data point is 225. the data may fully affect 200, but also influence 300 a little bit, and maybe even 400 ever so slightly. this allows interpolation so that the changes naturally smooth themselves and generate likely trims even beyond where the data actually exists. your results may vary. i expect people to use geometric when their ve table is really far out, and then maybe loose cell for fine tuning.

  7. #7
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    Figured it out, thanks for the explanation. And thanks for all the time you put into developing this tool to help the community!

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