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Apexi "air Fuel Ratio" How Accurate?

Discussion in 'ECU's, Electronics, and Tuning' started by tomtom, Apr 15, 2003.

  1. tomtom

    tomtom Senior Member

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    apexi s turbo timers have a air fuel ratio meter built in.
    It looks great a small pen size and when u use the A/F ratio meter it doesn t bounce all over it gives u the ratio.

    my question is, is this pretty accurate?
     
  2. pissedoffsol

    pissedoffsol RETIRED

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    for a gauge, as good as it gets
    for tuning, not very.

    it uses the stock o2, not a wideband.
     
  3. Tonyd0821

    Tonyd0821 Banned

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    autometer boost and a/f guages any good?
     
  4. pissedoffsol

    pissedoffsol RETIRED

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    their a/f guage is useless.
    you want a gauge that has numbers... not a bunch of lights that simply go back and forth.
    their boost gauge is ok... but there are much better options

    DEFI BF-series owns. I can't wait to get that setup.
     
  5. tomtom

    tomtom Senior Member

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    but the stock ecu uses the stock 02 to read air fuel ratio.

    If i use a wide band O2 to the apexi. Would that make it accurate?
     
  6. JDMFreak405

    JDMFreak405 Junior Member

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    in my opinion... autometer gauge are CRAP. for example a couple of my friends has tech,boost gauge and the a/f one... all POS. the tech bounce on low RPM.... not accurate and the boost gauge is off by and like pissedoffsol said "their a/f guage is useless."
     
  7. liquid00meth

    liquid00meth Senior Member

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    probably because they aren't setup right. lol. the a/f gauge is just a warning light pretty much. To use anything accurately you need wideband
     
  8. tomtom

    tomtom Senior Member

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    So ur saying u moms car isn t runing right!!!
    Her ecu is using a stock O2 to read air fuel

    And i can bet u 1000000000000000000000000000 dallors
    its running around 14.7-1
     
  9. CRX-YEM

    CRX-YEM Super Moderator Moderator VIP

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    I find the autometer a/f gage useful.
    I mean it's not gonna give you an exact number but for a quick indication
    of whether your running rich or lean under aceleration it's great.
     
  10. E_SolSi

    E_SolSi Member of the 20 nut club Moderator VIP

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    cut the bullshit fighting or this whole thread is gunna get deleted

    all you will get from a normal O2 sensor is a basic idea (ok for keeping an eye on wether your rich or lean but thats about it)
    a wide band O2 will be far more acurate (good for actual tuning)

    a wide band O2 will cost you $300+
    the kit for datalogging and real time monitoring will cost you $750+

    so if knowing your AF ratio is worth $1100+ to you then go for it

    now you still need something that will allow you to tune your AF ratio
     
  11. pissedoffsol

    pissedoffsol RETIRED

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    bullshit posts delted.

    don't do that shit again-- ALL OF YOU.

    now for the reasoning:
    --wideband vs regular ol' heated o2

    Most wideband meters have a 0-5 volt output proportional to air fuel ratio. That output is fed back into the O2 sensor wiring where <insert capture device > can turn it back into a precise air fuel ratio, just how your TPS uses 0-5volts for closed and wide open throttle. The stock O2 sensor is very inaccurate for anything other than 14.7:1 airfuel ratio.

    take a look:

    [​IMG]

    anything other than 14.7 (or just about stoich) the stock 02 sensor is useless. it will throw you a false result - a near constant voltage - , and in doing so, fuck up your entire tuning.

    The ECU aims to keep the air/fuel ratio close to the stoichiometric air/fuel ratio in order for the catalytic converter to work at maximum efficiency. This air/fuel ratio also gives good fuel economy. Under increased engine load the optimum air/fuel ratio is richer than the stoichiometric air/fuel ratio in order to give maximum engine output and prevent engine damage.

    An oxygen sensor produces an electric voltage from the different levels of oxygen present in the air and the exhaust gas. If the mixture is rich then the exhaust gas will contain very little oxygen. The oxygen sensor will therefore product a voltage output, which the ECU senses and determines that the fuel mixture is rich. Conversely if the fuel mixture is lean then the exhaust gas will contain higher levels of oxygen, which produces a lower voltage output. The normal range of the oxygen sensor output signal is about 0.2V to 1.2V It should be noted that most stock oxygen sensors are designed to be particularly sensitive around the stoichiometric air/fuel ratio

    most info graciously stolen fmo hondata.com
     
  12. tomtom

    tomtom Senior Member

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    about time some one put the smack down!!!
    Just remeber i didn t start the bullshit.
     
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