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308 79 Exhaust Pipes

Discussion in 'Technical Q&A' started by docweed, Nov 13, 2005.

  1. docweed

    docweed Formula Junior

    Dec 8, 2004
    452
    Morgantown,WV
    Full Name:
    Chuck Stewart
    Need some info, please. I was tweeking my air/fuel mixture screws and developed a miss and rough running engine. The cats have been removed but the system is stock I think (exhaust pipes and mufflers). My question is of the four pipes in the rear which ones corresponds to which carb? The two exhaust ports on the drive side blow out hot and with considerable amount of pressure. The two on the passenger side are not as hot and much reduced pressure. I tried to determine what carb went to what exh. port from the blowup picture but could not tell. Also once this is known can you tune the A/F mixture with a exhaust analyzer since two throats from each carb go out one tail pipe. Don't want to tap into each intake (maybe in another life).
     
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  3. Newman

    Newman F1 World Champ
    Professional Ferrari Technician Consultant Owner

    Dec 26, 2001
    13,670
    Canada
    Full Name:
    Newman
    If its the thermal reactor type muffler for 79 then who knows? Could mix both banks and I was told the 77 style was 2 seperate mufflers in the one mufler can after taking one apart that was garbage. The car also has test ports on the headers for what you are talking about rather than a general reading from the outlets.
     
  4. Newman

    Newman F1 World Champ
    Professional Ferrari Technician Consultant Owner

    Dec 26, 2001
    13,670
    Canada
    Full Name:
    Newman
    I forgot, the best you could do if the mufflers were seperate is one bank or the other but not down to which cylinder because of the 4 into 1 header.
     
  5. BillyD

    BillyD Formula 3
    Silver Subscribed

    Feb 28, 2004
    1,668
    Pacific Northwest
    Full Name:
    Bill
    Dam! I knew the answer a couple months ago but those brain cells have since blinked out. Pull a plug wire & u'll feel the difference on 1 side or the other. My best recollection is the rear cylinder bank is the passenger side exhausts but don't hold me to it.
    Bill
     
  6. 4Webers

    4Webers Formula Junior

    Nov 12, 2003
    276
    Texas
    Full Name:
    Darrell
    The stock 79 muffler mixes all of the inputs - there is no correlation between cylinders and what is coming out of any of the 4 muffler outlets. You need to use the small test ports to tune each carb throat.
     
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