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Thread: Muffler question

  1. #1
    Senior Member Chris Pomares's Avatar
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    Muffler question

    I have a question on what muffler to use for a current engine build. Here are it's specs.
    82SC case, crank, and heads,
    Single plug heads have new valves (stock size), guides, and fitted with MFI injectors.
    Four bearing S cams.
    10.2 CR Mahles with a 3.2 displacement. Maybe back CR off to 9.5?
    Rebuilt fuel pump with a custom Fairchild space cam. It might take a couple tries to get it just right.
    123 distributor.
    Newest SSI heat exchangers with 3mm bigger tubes.
    TRE supplied RSR size MFI induction. Here are a few pictures of the induction.

    Hoping for 230 plus HP.
    Muffler?
    2 in one out 70mm sport? Does the 70 mm outlet muffler make more power than the stock 60 mm or just more noise?
    2 in 2 out ?
    2 in 3 out. (2 out, plus single out with covers?)
    Attached Images Attached Images     
    Last edited by Chris Pomares; 08-01-2022 at 01:33 PM.
    1959 Auratium Green 356A Super w/ Rudge wheels
    1970 Irish Green 914-6 w/2.2S
    Current -1967 Bahama Yellow 912 POLO 2cam4 #1
    www.reSeeWorks.com
    Personalized Vintage Porsche's and parts
    I couldn't find the sports car of my dreams, so I built it myself-Ferdinand Porsche

  2. #2
    I think it’s important that you tell the group what your intentions for the car and engine are. As described with S cams it’s gonna be a very peaky motor. If you’re going to track it and it’s at 5500-7000 all the time, then you want something like megaphones or a full rally set up. If it’s mostly street then a twin single or standard twin sport is a great choice. The more flow you introduce you lose a bit of bottom end but gain HP up higher. I ran a pretty snappy 2.7 street motor for a lot of years, and I liked the twin in twin out musket style the best. It gave decent bottom end, good flow and great sound. Lots of opinions on exhaust, but purpose is important.

  3. #3
    Senior Member
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    +1 on 2 in 2 out factory sport. Best accidental purchase of my life. It is loud, but it is amazing. I think I’ve posted a few driving videos here, but you can hear it on Instagram (Rick71t). Below 3k is kinda annoying, a loud groan that some may like, but it makes it impossible to be quiet in town. The MFI will sound different though, as will the factory air cleaner. No heat exchangers though.

    I’ve run a gutted factory muffler, a factory muffler, a dansk sport, and the original 2-2 factory sport and nothing comes close to the factory sport (2in3out is very similar). My targa with SSI’s and dansk sport sounds like an angry vacuum cleaner by comparison, and it sounds amazing too. The induction helps, but MFI is better. If you really want, I’ll cut a clip of me putting around the paddocks or accelerating out of the pits to get the full sound. Just PM me to exchange emails.
    MBR #3926
    '71 911 T Targa "Rick White"
    '71 911 E "Karen"
    '70 S/T
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    '10 E61 "Vomit Comet"

  4. #4
    Senior Member Chris Pomares's Avatar
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    The owner of this build said he wants the single out sport. He gets what he wants, and that's the end of that story.
    1959 Auratium Green 356A Super w/ Rudge wheels
    1970 Irish Green 914-6 w/2.2S
    Current -1967 Bahama Yellow 912 POLO 2cam4 #1
    www.reSeeWorks.com
    Personalized Vintage Porsche's and parts
    I couldn't find the sports car of my dreams, so I built it myself-Ferdinand Porsche

  5. #5
    Moderator Chuck Miller's Avatar
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    Chris,

    I would suggest using a Leitritz or Bichoff factory muffler if you can find one... remember you can use a midyear 74-76 muffler and replace the 'bent' exit pipe with an early one.... I found they also made more stainless mufflers in the midyears....

    This is what I've had on my 2.7 / 9.5 rebuild forever with about 230HP... with all the snap you would want...
    ... and it's quite... .... not sure if that's a good thing with the owner...

    cm
    Chuck Miller
    Creative Advisor/Message Board Moderator - Early 911S Registry #109
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    TYP901 #62
    '73S cpe #1099 - Matched # 2.7/9.5 RS spec rebuild
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  6. #6
    Senior Member Chris Pomares's Avatar
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    Thanks Chuck.
    1959 Auratium Green 356A Super w/ Rudge wheels
    1970 Irish Green 914-6 w/2.2S
    Current -1967 Bahama Yellow 912 POLO 2cam4 #1
    www.reSeeWorks.com
    Personalized Vintage Porsche's and parts
    I couldn't find the sports car of my dreams, so I built it myself-Ferdinand Porsche

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