A question in ECU theory for the stooges... | FerrariChat
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A question in ECU theory for the stooges...

Discussion in '348/355' started by Marco Bussadori, Nov 4, 2008.

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  1. Marco Bussadori

    Marco Bussadori Formula Junior

    Aug 6, 2007
    430
    London
    Full Name:
    Marco Bussadori
    #1 Marco Bussadori, Nov 4, 2008
    In closed loop ops, the 348 uses the 02 sensor for idle/part throttle (2.5 - full variance on the 2.7) fueling control. The MAF tells the ECU how much air goes in, the O2 sensor tells it how to adjust the fueling based on standard curves to have minimum excess O2 in the exhaust and everything is happy.

    If we go to wide open throttle, and say had a bigger throttle opening, though all the air goes through the MAF, with the assumption that the injectors were able to deliver the fuel quantity, would our ECU freak out or would it just increase the duty cycle to ensure the right O2 sensor reading results?

    If the latter is the case, then in theory, adding larger injectors with some sort of airflow augmentation would mean more air + more fuel = more power and that our ECUs probably have another 10-15% of free power to give us for practically free just by getting more air to flow into the plenum... Above 15% they would freak and go into limp-home mode no?

    Just a question. I have a spare plenum and am willing to modify to explore...

    Marco
     
  2. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,620
    The Brickyard
    Full Name:
    The Bad Guy
    #2 ernie, Nov 4, 2008
    That seems to be thing thinking.

    The only 348 owner I know of that has done this is Dave (group77racing). From what I can remember he is running bigger injectors, larger MAFS', larger TB's, bigger fuel lines from the pumps, and a SWEET custom intake plenum. As far as I can tell he's running it with the stock ecu's?????? But I don't know for sure?
     
  3. No Doubt

    No Doubt Seven Time F1 World Champ

    May 21, 2005
    72,740
    Vegas+Alabama
    Full Name:
    Mr. Sideways
    #3 No Doubt, Nov 4, 2008
    You'll know that you are flowing too much air when you start getting lean. Once the MAF signal reaches 5 volts, it plateaus no matter how much more air goes into your intake. Since that signal can't go any higher, your ECUs won't know to add more fuel after that point.

    How much though? 10%? 20%? 40%? 320hp doesn't use up all 5 volts. Since the 348's delivered to Michelotto had 360 hp from Ferrari prior to tuning, that's probably the peak point for our MAFs (guessing).
     
  4. hotrod406

    hotrod406 Formula Junior

    Sep 18, 2007
    540
    Grand rapids area,MI
    Full Name:
    Tim
    #4 hotrod406, Nov 5, 2008
    Most ecu's go to a standard table and do not use O2 readings at full throttle. Standard narrow band O2 sensors are not accurate enough at the air/fuel ratios needed for max power. It is possible that the computer will read the MAF table and adjust fuel accordingly, I'm not sure about that.
     

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