355 2.7 and 5.2 back box, interchangeable? | FerrariChat
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355 2.7 and 5.2 back box, interchangeable?

Discussion in '348/355' started by Slickmk1, Oct 27, 2015.

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  1. Slickmk1

    Slickmk1 Karting

    Jul 22, 2014
    83
    United Kingdom
    Full Name:
    Mark
    #1 Slickmk1, Oct 27, 2015
    Ok,

    So ther is a couple of bits about this around but just wanted to get a definitive answer.
    My 95b currently has a tubi style back box. The top pipe where the bypass valve connects to has the take off for the post valve thermo couple that only the later cars had. It just has a cap over it which can be taken off and replaced with the sensor. On closer investigation tubi style only actually offer one back box for the 355 regardless of 2.7 or 5.2. This clearly must fit both cars.

    So we all kno the headers are different, bypass pipe (y pipe) different and cats but ultimately did the actuall pipe position for the back box end up the same?

    Now I know Ferrari list different part numbers but the stock systems sound different 2.7 to 5.2 so other than the thermo couple outlet could this be nothing more than superceeded?
     
  2. Markphd

    Markphd Formula Junior

    Mar 10, 2012
    713
    #2 Markphd, Oct 27, 2015
    The key to understanding 2.7 to 5.2 differences is that the 2.7 setup is essentially treating the engine as two separate 4 cylinder motors. My guess is that anything to do with the bypass is only controlled by a single ECU bank (and not influenced by both banks). The 5.2 setup is treating the motor as a single entity and opposed to two banks of 4. This is why there is only one MAF on a 5.2 care and two on the 2.7 cars. I haven't looked at the 2.7 ECU but it wouldn't surprise me to see two separate ECU's essentially running the engine on the 2.7 cars (went back and verified, there are two ECU's on the 2.7 cars). So I would expect the exhaust bypass to only be under control of one of the two ECU's, which would explain how the mechanisms can be related without being completely dissimilar or identical.
     
  3. Slickmk1

    Slickmk1 Karting

    Jul 22, 2014
    83
    United Kingdom
    Full Name:
    Mark
    #3 Slickmk1, Oct 27, 2015
    I get that but this is about a physical mechanical fitment. Ie, if I get a capristo back box from a 5.2 is it gonna fit my 2.7. The ecu side of things really has nothing to do with the exhaust fit.

    Obviously I would have to cap off the take off for the thermocouple as is my tubi at the moment. But do all the pipes line up as they should?
     
  4. phrogs

    phrogs F1 Veteran
    Silver Subscribed

    Apr 13, 2004
    7,342
    Kzoo Michigan
    #4 phrogs, Oct 27, 2015
    Last edited: Oct 27, 2015
    I have had my Capristo bolted up to my 2.7 and my 5.2. It fits, My 5.2 Is a euro and Doesn't have the third thermocouple so I still have to cap that extra hole too.
     
  5. 97 Spider

    97 Spider Formula 3

    Dec 15, 2012
    2,241
    Texas
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    Brian
    #5 97 Spider, Oct 27, 2015
    A 5.2 has two engine ECUs also, one running each bank of 4. Going to one MAF didn't change Thier engine management philosophy just both other them getting info from it. 360s are ran the same way etc etc.
     
  6. Markphd

    Markphd Formula Junior

    Mar 10, 2012
    713
    #6 Markphd, Oct 27, 2015
    No, I am quite sure that the 5.2 cars have only 1 ECU

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    That is the ONLY fuel and ignition ECU for my 97 spider. Which is a 5.2 car.

    Sent from my SM-G920P using Tapatalk
     
  7. Slickmk1

    Slickmk1 Karting

    Jul 22, 2014
    83
    United Kingdom
    Full Name:
    Mark
    #7 Slickmk1, Oct 28, 2015
    Awesome, my buddy said I can swap the exhaust over as he isn't bothered about the capristo. Happy days for me!! Just didn't want to get them both stripped down to then find it didn't fit.
     
  8. 97 Spider

    97 Spider Formula 3

    Dec 15, 2012
    2,241
    Texas
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    Brian
    #8 97 Spider, Oct 28, 2015
    Really? I have a 97 too and I always assumed it had two. My bad for stating false info then. I knew everything leading up to the 5.2 had been ran as two engines and the 360s I parted out definitely had two ECUs again so they must have just done one for a few years. I just assumed with the SDLs being able to shut down one bank and that sort of stuff it must still be he standard two ECUs. I guess you learn something new every day.
     
  9. Markphd

    Markphd Formula Junior

    Mar 10, 2012
    713
    #9 Markphd, Oct 28, 2015
    No worries, it's fun to learn something new...

    Sent from my SM-G920P using Tapatalk
     
  10. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    13,541
    San Carlos, CA
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    Mitchell Le
    #10 yelcab, Oct 28, 2015
    The 348 with 2.7 ECUs were two ECUs, mounted in the passenger compartment behind the seats.
    The 355 2.7 has 2 ECUs in the engine bay (wonder why they moved it out there just for 1 year)
    When they went to 5.2, it became 1 ECU OBD2 compliant, mounted in the passenger compartment behind the seat.
     
  11. vvassallo

    vvassallo F1 Veteran

    Aug 4, 2006
    8,323
    Palos Verdes
    Full Name:
    Vince V
    #11 vvassallo, Oct 29, 2015
    Mitchell they put the 355 2.7 ECUs there to die. ;)
     
  12. Markphd

    Markphd Formula Junior

    Mar 10, 2012
    713
    #12 Markphd, Oct 29, 2015
    Well my 5.2 ECU will be remaining off my F355 forever... Goodbye.... Motronic and hello Megasquirt... I have been reluctant to pitch the factory setup, but it is time for all things motronic to end in this car and to run something much more advanced (putting on my flame suit).
     

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