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Thread: ideal bore size

  
  1. #1
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    ideal bore size

    whats the ideal bore for an exhaust for the 1.8 coupe???

    2.5 inch sound about right or is this ideally for the turbo, i dont wanna loose power by puting a perfomance exhuast with the wrong bore on


    any help greatfully recieved as always
    Astra Se2 coupe

    "Love it and shove it and dance around the bucket"

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    haulme's Avatar
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    hi mate

    i use a 2.25 on mine, seems fine. i dont think the 1.8 coupe produces enough exhuast fumes to use the entire dimension 2.5" and it will just start sounding loud.

    I think 2.25 is a good bet. As you know my approach is to go for power/torque rather than the bark.
    Drives:Mazda 6 MPS- Zoom Zoom

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    2.25" is the max id go on a NA

    2.5" is ideal IMO on the ZLET (and thats what i opted for) 3" is just overkill IMO
    Standard 2" or oversized 2.25" on the NA models is what I would recommend.

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    dam it cos this is a cheap cat back

    would the oversize bore kill performance or wud it not notice????
    Astra Se2 coupe

    "Love it and shove it and dance around the bucket"

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    i wouldnt risk it

    performance is a finicky business on the 1.8s. horses are king. you cannot really mess about to much otherwise you have a lumpy car.
    Drives:Mazda 6 MPS- Zoom Zoom

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    dam it, may aswell post the link for some othe lucky git then lol
    Astra Se2 coupe

    "Love it and shove it and dance around the bucket"

  7. #7
    fdrightup
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    my astra runs 52mm inside diameter exhaust that is a 1.4,
    1.4/1.6 50mm to 62.5mm 1.8/2.0 75mm to 92mm inside diameter but this depends on how much the engine is tuned

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    EDIT: Post removed - im speaking rubbish (as per usual)

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