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Trying to identify exhaust system. U.S. 308 ?

Discussion in '308/328' started by TTR, Feb 3, 2021.

  1. TTR

    TTR F1 Rookie
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    Timo
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  3. miketuason

    miketuason F1 World Champ
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    The exhaust manifold looks stock but the muffler looks like a Stebro muffler.
     
  4. TTR

    TTR F1 Rookie
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    Thank you. Anyone else able to confirm Mike’s suggestion regarding the muffler ?
    The muffler weighs almost 100 lbs !?!
    Any ideas on years these may fit ?
     
  5. nerofer

    nerofer F1 World Champ

    Mar 26, 2011
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    I'm not an expert on 3x8 U.S exhausts systems, BUT we have a serious clue here: there is only one model I know in the whole 3x8 family that has exhaust pipes that discharge downwards (at 90° angle) inside "false" straight exhaust pipes, and that's the 308 GT4...note also that the exhaust tubes from each cylinder are round, not oval, so this is a system for a two-valve engine, not a four-valve. Pretty sure (= 95%) this is a 308 GT4 US exhaust.

    Rgds
     
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  6. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #5 Steve Magnusson, Feb 3, 2021
    Last edited: Feb 3, 2021
    +1 -- early US 308GT4, insulated headers, thermal reactor muffler (the heavy insulation is what makes it so heavy), before model year 1978 (which added cats). The service bulletin that showed the modification to the downward tailpipes to appear as straightback tailpipes:
     

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  8. TTR

    TTR F1 Rookie
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    Thank you all gentlemen !

    So about ‘75-‘77 U.S. market 308 GT4 ?
     
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  9. Brian Harper

    Brian Harper F1 Rookie
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    I had a 1975 GT4. Yes to the above.
     
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  10. RicSinger

    RicSinger Formula Junior

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  11. RicSinger

    RicSinger Formula Junior

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  13. TTR

    TTR F1 Rookie
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    Thanks.
    I thought it would be likely OEM since a friend who gave it to me owned dozen or so new or late model Ferraris in late-‘70s/early-‘80s, including couple of different 308s.
    He told me he had many of them slightly “improved/upgraded” by having some smog equipment removed and aftermarket exhaust installed, etc.
    This system looks like having beenremoved when it was nearly new.

    I just can’t get over how heavy the muffler is. :confused:
    OTOH, the entire OEM U.S. 365 GTB/4 (“Daytona”) exhaust system weighs about 200 lbs !?!
     
  14. Brian Harper

    Brian Harper F1 Rookie
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    It has the exhaust exit out the bottom with fake tips on a GTB? I thought only the GT4 had that. The service bulletin Steve posted above calls out the GT4 for this modification in 1975. I'd expect that every car coming out of the factory years later would have this done. I suspect that if you have the bottom exit exhaust that someone swapped in a GT4 system to your car at some point.
     
  15. nerofer

    nerofer F1 World Champ

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    + 1, that would be my guess also...only the early US GT4s had the downwards exhaust exit with fake straight pipes.

    Rgds
     
  16. Brian Harper

    Brian Harper F1 Rookie
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    I didn't know it was USA-only for the downward exit. Probably we had some strange law that required this?? Thermoreactor exhaust was so hot as to shoot out the back and catch passerby's pant legs on fire? Whatever it was, it was gone in 1976 apparently.
     
  17. BigTex

    BigTex Seven Time F1 World Champ
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    It was a NON CAT, "thermoreactor" so it ceased in 1978, when catalytic converters were added.

    There were not a HUGE number of the new 308GTBs in 76 and '77 in this country, but I don't think many had the dual tips.
    RicSinger we need to get you a nice ANSA!
     
  18. nerofer

    nerofer F1 World Champ

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    ...IF someone would be kind enough to spare a few minutes, and a few short lines, to explain in plain language to this stupid Frenchman here what "Thermoreactor" actually means, I would be grateful...
    I understand this is a kind of "emission control device", before the catalytic converter, more or less? But what is it, actually? What's inside the "thermoreactor"?

    (Remember, as I write often, that no member of the "3x8" family here in "Continental Europe" ever had ANY emission control device; except the swiss/sweden market 328s; even the first 40 or so Euro "Mondial "T" were not catalysed)

    Rgds
     
  19. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    Thermoreactor (also called a thermal reactor) = It's just a very well-insulated muffler whose purpose is to keep the mixture of hot exhaust gases and the air added by the air injection system as warm as possible so that the O2 in the air injection air reacts as much as possible with the CO in the exhaust gas to form CO2 (and reduce the amount of CO leaving the tailpipes). See page O9 in the 308GT4 WSM.
     
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  20. nerofer

    nerofer F1 World Champ

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    Thanks Steve, appreciated. I shall go to bed less dumb tonight ("Je me coucherai moins bête ce soir").

    Rgds
     
  21. BigTex

    BigTex Seven Time F1 World Champ
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    It was all ********, in an Italian way...:D :D :D
     
  22. JCR

    JCR F1 Veteran
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    They were not installed on European market cars. These were primitive emission devices on some European to USA exports that were used for a few years in the mid 70s. On 911 and BMW sixes they were know for "cooking" the engine. Those engines had a much shorter life than normal.
     
  23. RicSinger

    RicSinger Formula Junior

    Mar 13, 2016
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    Hi Brian
    I’ve been told the car has its original exhaust, it’s a 2 owner car with 20+ years of ownership each.

    For the looks of it, it does not looks as it it was a replacement.

    My 1979 GT4 had the exhaust you can see in the photo above



    Sent from my iPhone using FerrariChat
     
  24. RicSinger

    RicSinger Formula Junior

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    @BigTex yes Sir, I like Tubi but am just not wanting to spend the $3,000+ that it costs , as you know I am 90% into the full restoration of the 89 Mondial and I just did a super big engine out, tear down etc of my 1985 400i

    The 77 GTB is getting the Seats and door panels redone.

    I’ll keep you posted on exhaust developments


    Sent from my iPhone using FerrariChat
     
  25. JuLiTrO

    JuLiTrO Formula Junior

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  26. TTR

    TTR F1 Rookie
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    GT4 or GTB/GTS ?
     
  27. JuLiTrO

    JuLiTrO Formula Junior

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    Mine is a GTB
     
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  28. TTR

    TTR F1 Rookie
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    Thank you.
    This, along with RicSinger's assertion and my friends recollection* appears to suggest this system was possibly also used in some U.S. GTBs.

    * I spoke to him couple of days ago and doesn't recall having owned or even driven a GT4, but had a GTB and a GTS +/- 40 years ago.
    He said he had this system replaced with some lighter and "better sounding" aftermarket set up, but kept these pieces in case he had to get the car smogged later and probably sold the car before it became necessary.
     

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