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Thread: Please explain Delta MAP Kpa...

  1. #51
    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by mr.prick View Post
    My definition of Delta_MAP is the actual (not percentage) difference of
    the current frames MAP value from the last.
    PHP Code:
    #Units       Low      High     Fmt       Expression
    #------- ---------- --------- -------- -------------------------------------------
    psi         -16        16      .0        "({SAE.MAP.psi})-value({SAE.MAP.psi},frame()-1)"
    kPa         -105      105      .0        "({SAE.MAP.kPa})-value({SAE.MAP.kPa},frame()-1)" 
    Hi Mike,

    In this thread's context, DeltaMAP is the pressure difference across any one injector, as used by E38/E67 calibration files.

    See next post.

  2. #52
    Joe (Moderator) joecar's Avatar
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    Default DeltaMAP = pressure difference across any one injector

    absolute rail pressure = gauge rail pressure + BARO

    MANVAC = BARO - MAP

    DeltaMAP = absolute rail pressure - MAP = gauge rail pressure + MANVAC


    gauge rail pressure is typically 400kPa (58psi).

  3. #53
    Senior Member mowton's Avatar
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    Default Scaled tune question on IFR

    Quote Originally Posted by joecar View Post
    deltaMAP = pressure difference across injector = absolute rail pressure - MAP

    note: absolute rail pressure = 500kPa absolute = 400kPa gauge (58psi gauge)

    e.g.
    deltaMAP=400kPa --> at WOT with NA
    deltaMAP=440kPa --> cruise with OEM cam (40kPa vacuum)
    deltaMAP=460kPa --> idle with OEM cam (60kPa vacuum)
    deltaMAP=500kPa --> theoretical full vacuum (100kPa vacuum)

    deltaMAP<400kPa --> boost (MAP > 100kPa)
    I know this is an old thread, but does this mean we only have to scale IFR to 500 (flat line 63.5 beyond) which with large injectors will provide more low level granularity for certain scaled tables like timing.

    Thanks,

    Ed M

  4. #54
    Joe (Moderator) joecar's Avatar
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    Yes, only up to 500 kPa.

  5. #55
    Lifetime Member izaks's Avatar
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    I know this is an old thread, but

    Here are some results of testing Holden's fitted with the E38 (all at altitude KOEO 84-85 kpa)

    If the car is not fitted with an FSCM, INJPDELTA will not record below 400 KPA (irrespective if NA or boosted)
    If the car is fitted with an FSCM but switched off in the ECM, INJPDELTA will not record below 400 KPA (irrespective if NA or boosted)
    If the car is fitted with an FSCM and is enabled, INJPDELTA will record less than 400 when boosted. The INJ PW also increases compared to FSCM switched off. (INJPDELTA now less than 400)
    When in boost, INJPDELTA does not follow the calculation posted earlier. (still trying to understand why)
    Some examples of logging
    MAP INJPDELTA_DMA
    kPa kPa
    84 415.6
    84 415.6
    84 415.6
    84 415.6
    84 415.6
    84 415.6
    84 415.6

    MAP INJPDELTA_DMA
    kPa kPa
    164 375
    167 380
    175 383
    190 381
    195 368
    199 365
    198 351
    195 330
    191 355
    194 352
    198 354
    2011 VE SSV 419 + CAM + Whipple 2.9FF SC + PPV front struts + Bilstein rear shocks + 6L90E with single piece carbon fiber prop

  6. #56
    Joe (Moderator) joecar's Avatar
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    Good question... it seems the ECM has knowledge and/or control of the pressure produced by the FSCM, so the above math relationships are broken.

  7. #57
    Lifetime Member izaks's Avatar
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    It makes some sense when you compare the injector flow base of non FSCM and FSCM equipped cars
    FSCM cars have a fuel pressure sensor and the IFB caters for boost, which the non FSM do not

    NON FSCM (flat line from 400) sq root
    LABELS Injector Flow Base (Grams/Second)
    Delta MAP kPa Value
    128 5.337646
    144 5.337646
    160 5.337646
    176 5.337646
    192 5.337646
    208 5.337646
    224 5.337646
    240 5.337646
    256 5.337646
    272 5.337646
    288 5.337646
    304 5.337646
    320 5.337646
    336 5.337646
    352 5.337646
    368 5.337646
    384 5.337646
    400 5.337646
    416 5.478027
    432 5.615112
    448 5.748779
    464 5.879394
    480 6.007446
    496 6.007446
    512 6.007446
    528 6.007446
    544 6.007446
    560 6.007446
    576 6.007446
    592 6.007446
    608 6.007446
    624 6.007446
    640 6.007446

    FSCM (slope)
    LABELS Injector Flow Base (Grams/Second)
    Delta MAP kPa Value
    128 2.974609
    148 3.198486
    168 3.407959
    188 3.604980
    208 3.791992
    228 3.969970
    248 4.140625
    268 4.304199
    288 4.461914
    308 4.614257
    328 4.761718
    348 4.904785
    368 5.043701
    388 5.178955
    408 5.310790
    428 5.439453
    448 5.564941
    468 5.687988
    488 5.808105
    508 5.926025
    528 6.041503
    548 6.154785
    568 6.266113
    588 6.375488
    608 6.483154
    628 6.588867
    648 6.692870
    668 6.795409
    688 6.896484
    708 6.995849
    728 7.093993
    748 7.190917
    768 7.286376
    2011 VE SSV 419 + CAM + Whipple 2.9FF SC + PPV front struts + Bilstein rear shocks + 6L90E with single piece carbon fiber prop

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