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348 Induction System

Discussion in 'Technical Q&A' started by MarkCollins, Dec 9, 2003.

  1. MarkCollins

    MarkCollins F1 Rookie
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    Jul 2, 2002
    3,199
    South England
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    Mark Collins
    I'm trying to understand how it works or more specifically what the additional butterfly is for. It is sited between the two banks and seems ot be controlled by a Vacuum valve

    Anybody know what it is for or when it opens and why

    thanks
     
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  3. rexrcr

    rexrcr Formula 3

    Nov 27, 2002
    1,572
    Kalamazoo, MI
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    Rob Schermerhorn
    Wave tuning the intake air. Separate banks at lower rpm for improved torque, open plenum for high rpm power.

    Can't remember specific opening protocol. It's in WSM.

    Best regards,

    Rob Schermerhorn
     
  4. Miltonian

    Miltonian F1 Veteran

    Dec 11, 2002
    5,964
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    Jeff B.
    Mark: Try to find yourself a copy of Enrico Benzing's book on the 348, in the "Automobilia" series. It is/was available in both hardback and paperback, and it has a lot of good information on the design of the car, including a great description of the manifolding system.

    I was also looking at the "Ferrari Story" issue on the 348 for details about the manifolds, and I was amused to see the quote that the Bosch Motronic system "....uses the hot wive device for measuring the air flow." Sounds like a tempermental component to me.
     
  5. Korr

    Korr F1 World Champ
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    Dec 7, 2003
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    Newton Earl Anderthal
    Miltonian,

    That wire you speak of is the Mass Airflow Sensor. It is given constant voltage, which heats the wire. Air flowing through the channel that it is in cools it, dropping its resistance and allowing more current to flow through it. More current must then be applied to keep the wire at a constant temperature. These changes in current are then interpreted by the computer as airflow.

    A pretty simple system, and it works fairly well!
     
  6. MarkCollins

    MarkCollins F1 Rookie
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    Jul 2, 2002
    3,199
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    Mark Collins
    Thanks for the replies

    I think Korr was referring to a typo where it states it uses a 'hot wive'
     
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  8. Korr

    Korr F1 World Champ
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    Newton Earl Anderthal
    I see, my apologies, then!

    I can be tragically daft in the morning.
     
  9. Korr

    Korr F1 World Champ
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    Dec 7, 2003
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    Newton Earl Anderthal

    I'm glad my brakes don't fade as much as my brain does in the morning!
     
  10. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    7,661
    Both chambers the feed each bank are Helmholtz resonators, and are turned for the upper end of the rev range. The valve that connects the two resonators alters the resonance point for better TQ in the lower end of the rev range.

    Do a google on "helmholtz resonators" and "engine tuning"
     
  11. MarkCollins

    MarkCollins F1 Rookie
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    Jul 2, 2002
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    Mark Collins
    Mitch

    thanks for that, now I need to find out what controls it ie what tells it to open and whilst I can see it is Vacuum driven I'm wondering if there is a solenoid in the line and that the ECU(s) controls
     
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