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Thread: 08 E38 LS7 Injector Flow base

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    Member Age08's Avatar
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    Default 08 E38 LS7 Injector Flow base

    Is there a custom OS that allows larger flow rates for 08 E38?
    Currently in process of installing a blower on LS7 and it came with 80lb@ Bar3 injectors,(plans to run E85 in future).
    I see the tune max out at 7.99 grams/sec for injector flow base and a 09 ZR1 tune is good for 15.99 grams/sec.

  2. #2
    Joe (Moderator) joecar's Avatar
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    If the 16 g/s OS is not compatible with your ECM, then you have to scale...

    ( you can scale IFR/STOICH_AFR to avoid having to shift-down many tables )

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    Member Age08's Avatar
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    I just read about doing it that way, I was gonna try just with IAT multipler, have you tried this way before?

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    Member Age08's Avatar
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    does anyone have a stock tune for 2011 Z06 LS7?

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    Joe (Moderator) joecar's Avatar
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    You could also use the IAT multipler to scale.
    Last edited by joecar; November 13th, 2017 at 11:38 AM.

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    Member Age08's Avatar
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    Joe,
    what tables do you mean B4001 & B3671?
    I have tried the IAT multiply to scale but it doesn't seem to work very if at all, If I understand correctly that IAT multiplier would do this B4001 * B1213 = a number that is greater then 7.99? so the pcm would reduce injector pulse to produce correct rate.

  7. #7
    Joe (Moderator) joecar's Avatar
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    Yes.

    Please post your tune file (if you can), I want to look at the injector tables.

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    Member Age08's Avatar
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    attached is modified IAT modifier as well as the injector flow correction from the injectors.
    E38_0005.ctz
    I just tried adjusting the stoich_afr my the % difference in IFR and the car idles not bad. The question I have isn't changing that gonna screw up the closed loop afr?

  9. #9
    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by Age08 View Post
    ...
    I just tried adjusting the stoich_afr my the % difference in IFR and the car idles not bad. The question I have isn't changing that gonna screw up the closed loop afr?
    No it will not mess up closed loop... LTFT/STFT detemine closed loop, and you will see SAE.LAMBDA be hovering right on 1.00 in CL (even tho the commanded AFR shows 29.36).

    ( remember: the ECM uses EQR and/or Lambda for fueling, AFR is for your viewing purposes, not for running/tuning )

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    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by Age08 View Post
    Joe,
    what tables do you mean B4001 & B3671?
    Yes, those two tables... they scale inversely wrt each other (for example: B4001 * 0.75, B3671 / 0.75)

    I have tried the IAT multiply to scale but it doesn't seem to work very if at all, If I understand correctly that IAT multiplier would do this B4001 * B1213 = a number that is greater then 7.99? so the pcm would reduce injector pulse to produce correct rate.
    You would go B4001 * X and B1213 / X where X is your scale factor (e.g. 0.75 in the example above)...

    i.e. so now B4001 is below its 8 g/s or 16 g/s limit, but B1213 corrects it to produce the actual flowrate.
    Last edited by joecar; November 16th, 2017 at 05:19 AM.

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