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Thread: Maf limit questions

  1. #1
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    Maf limit questions

    A constant learning process, so a few questions.

    I am running the 2 bar OS which extends the maf tables but on scans I still max the maf at 11400 and 655 g/sec. I searched and found a statement by Bill that this is the limit of the pid.
    If the pid only goes to these levels, how do you tune after that level? Why would they extend these tables, and then limit the pid so its unusable ?
    2007 Corvette C6 Vert. A6
    LME LS402, Pat G custom cam, ATI 10% OD Damper
    Circle D triple disc 2600, 3.42 Diff
    YSI, 3.0 pulley, ID 1000's
    Alky Control Meth,
    ARH 1 7/8 headers,
    1009 RWHP @ 7000, 817 RWT @ 6000

  2. #2
    Senior Tuner DSteck's Avatar
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    The PID is an OBD-2 reporting limit. Log dynamic airflow, not MAF airflow.

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  3. #3
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    Thanks Dave... So what is the right way to tune the maf over the limit ? Dynamic airflow against maf freq ?? is that possible.??
    2007 Corvette C6 Vert. A6
    LME LS402, Pat G custom cam, ATI 10% OD Damper
    Circle D triple disc 2600, 3.42 Diff
    YSI, 3.0 pulley, ID 1000's
    Alky Control Meth,
    ARH 1 7/8 headers,
    1009 RWHP @ 7000, 817 RWT @ 6000

  4. #4
    Senior Tuner DSteck's Avatar
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    You don't need to see airflow in the scanner. Log wideband error against MAF frequency.

    DSX Tuning - Authorized HP Tuners Dealer
    http://www.dsxtuning.com
    http://www.facebook.com/dsx.tuning
    Just say no to bull s***.
    IF YOU WANT HELP, POST A FILE!

  5. #5
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    Quote Originally Posted by DSteck View Post
    You don't need to see airflow in the scanner. Log wideband error against MAF frequency.
    This is so true. I dont even see airflow in the scanner. My brain had a hiccup. I was looking at a log and this whole thing came to mind. Thanks again.
    2007 Corvette C6 Vert. A6
    LME LS402, Pat G custom cam, ATI 10% OD Damper
    Circle D triple disc 2600, 3.42 Diff
    YSI, 3.0 pulley, ID 1000's
    Alky Control Meth,
    ARH 1 7/8 headers,
    1009 RWHP @ 7000, 817 RWT @ 6000

  6. #6
    Tuner 07MontRedcp's Avatar
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    Another good question is, why in the world would they extended the maf tables but not the IFR tables?

    BJK
    APS TT 630 rwhp/654 rwtq @ 9 psi
    '07 C6, TR6060 conversion w/Z06 ratios. DTE Stage 4 Quaife Diff w/brace (3.73). Z06 Brakes, mild turbo cam & dual springs (222/222, LSA 115, .581/.581), LS9R clutch, LG GT2 Coilovers, Autometer Cobalt Fuel gauage, Progressive Alky Controller, and e-Boost2 Controller. PFADT poly bushing for control arms and Sports sway bars. MGW shifter. 3" B&B Fusion. RSI Stage 1.5 fuel system. RX dual valve catch can.

  7. #7
    Senior Tuner DSteck's Avatar
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    Quote Originally Posted by 07MontRedcp View Post
    Another good question is, why in the world would they extended the maf tables but not the IFR tables?

    BJK
    This was asked before, and Chris alluded to a much larger undertaking in code modification to adjust the IFR table.

    DSX Tuning - Authorized HP Tuners Dealer
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    http://www.facebook.com/dsx.tuning
    Just say no to bull s***.
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  8. #8
    I haven't tested this, but could one not just max out the IFR table and then change the flow rate multiplier vs. IAT to compensate? So say you have 80 lb injectors, and you max out at 60, so in that IAT table across the board put in 1.35 ?

    Instead of changing Stoich.

  9. #9
    Senior Tuner DSteck's Avatar
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    Doesn't work. It's a hard limit after all modifiers.

    DSX Tuning - Authorized HP Tuners Dealer
    http://www.dsxtuning.com
    http://www.facebook.com/dsx.tuning
    Just say no to bull s***.
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  10. #10
    Ohh dear thanks for the clarification.

    My fix was return fuel system and lowered fuel pressure, fixed soooo many nags makes tuning a dream by comparison.

  11. #11
    Tuner 07MontRedcp's Avatar
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    Quote Originally Posted by mourat View Post
    Ohh dear thanks for the clarification.

    My fix was return fuel system and lowered fuel pressure, fixed soooo many nags makes tuning a dream by comparison.
    Same here.
    APS TT 630 rwhp/654 rwtq @ 9 psi
    '07 C6, TR6060 conversion w/Z06 ratios. DTE Stage 4 Quaife Diff w/brace (3.73). Z06 Brakes, mild turbo cam & dual springs (222/222, LSA 115, .581/.581), LS9R clutch, LG GT2 Coilovers, Autometer Cobalt Fuel gauage, Progressive Alky Controller, and e-Boost2 Controller. PFADT poly bushing for control arms and Sports sway bars. MGW shifter. 3" B&B Fusion. RSI Stage 1.5 fuel system. RX dual valve catch can.