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X pipe for 365 GTB/4 ?

Discussion in 'Vintage (thru 365 GTC4)' started by arm7, Nov 23, 2008.

  1. arm7

    arm7 Rookie

    Aug 13, 2006
    23
    Newport Beach, Ca
    I had a custom exhaust made for a US Daytona to get the extra diameter that the Euro cars had and the builder suggested a cross pipe- any thoughts

    Tony
     
  2. FERRARI-TECH

    FERRARI-TECH Formula 3

    Nov 9, 2006
    1,603
    Full Name:
    Ferrari-tech

    I Know Larini in the UK have done custom work for older cars, give them a call and ask them, they have done all the head scratching and probably have your answer figured out.

    Good luck, let us know how it works out.
     
  3. Telerding

    Telerding Formula Junior

    Sep 30, 2004
    362
    Santa Maria/CA
    Full Name:
    Tom Elerding
    #3 Telerding, Nov 23, 2008
    Last edited by a moderator: Sep 7, 2017
    Depends on what mufflers you are running. If you keep your stock mufflers, then no. If you remove the mufflers, then yes.

    According to Carobu Engineering, the rebuilder of my motor, the stock ANSA front mufflers on each side did mix the gasses from the front 3 and rear 3 cylinders. If you just put straight pipes in, and remove all of the center mufflers as I did, you get a torque hole between about 3500 and 5000 RPM or so.

    Carobu recommended putting in crossovers at about the spot where the front muffler used to be. Dyno results show the torque hole was removed by this. Note that the crossovers are only between the 2 pipes on each side.

    I can post the dyno comparison if you need it. The X-pipes were built by Burns Stainless in Costa Mesa, CA
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  4. 2NA

    2NA F1 World Champ
    Professional Ferrari Technician Owner Consultant

    Dec 29, 2006
    17,654
    Twin Cities
    Full Name:
    Tim Keseluk
    What does the O2 sensor do?
     
  5. Telerding

    Telerding Formula Junior

    Sep 30, 2004
    362
    Santa Maria/CA
    Full Name:
    Tom Elerding
    Bungs were put in on each X pipe to allow measurement of Air/fuel ratio for engine tuning on the dyno. This allowed Carobu to tune the carbs across the whole RPM range.

    I've posted this before, but to see the engine running on the dyno, go to: http://www.youtube.com/watch?v=0PFdkRPK8iA
     
  6. arm7

    arm7 Rookie

    Aug 13, 2006
    23
    Newport Beach, Ca
    Very helpful, thank you. I have visited Carobu (very knowledgeable) and I love the idea of the exhaust monitoring duct.

    Calling Larini is a good call as well, Thanks.
     

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