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Removing cat?

  • 22-06-2010 6:41pm
    #1
    Registered Users, Registered Users 2 Posts: 37


    Hi, i have an '02 Honda Civic 1.7 cdti, would removing the cat give it that 'booow' sound? And would it result it the car being more smokey or less reliable?
    Thanks.


Comments

  • Registered Users, Registered Users 2 Posts: 18,272 ✭✭✭✭Atomic Pineapple


    No that "booooww" sound is an atmospheric dump valve.

    It will result in high emissions but I dont think you'd notice more smoke, not sure on a diesel, shouldn't affect reliability too much.


  • Registered Users, Registered Users 2 Posts: 9,593 ✭✭✭tossy


    The cat on a diesel is really only there for the greens,a de cat diesel would probably still pass the NCT.

    The "booooow" sound is ghey on diesels.


  • Closed Accounts Posts: 10,833 ✭✭✭✭Armin_Tamzarian


    draffodx wrote: »
    No that "booooww" sound is an atmospheric dump valve.

    booooow :confused:
    Is it not more of a psssssst sound?


  • Registered Users, Registered Users 2 Posts: 18,272 ✭✭✭✭Atomic Pineapple


    booooow :confused:
    Is it not more of a psssssst sound?

    Normally yes but with a butterfly valve I think its called it changes the sound to a "booooow"


  • Registered Users, Registered Users 2 Posts: 2,459 ✭✭✭zubair


    Donal199 wrote: »
    Hi, i have an '02 Honda Civic 1.7 cdti, would removing the cat give it that 'booow' sound? And would it result it the car being more smokey or less reliable?
    Thanks.

    Seeing as Donal is asking about the cat I'm sure he's talking about the exhaust and not a dv. Maybe the "booooow" was confusing.

    You don't have to go for a de-cat you could go for a Hi-flow/ sports cat, anything non-resonated will change the exhaust note. As for the side effects of the mod, I'm sure some honda/ diesel owners can give you more info from their experiences and recommend a setup.


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  • Registered Users, Registered Users 2 Posts: 18,272 ✭✭✭✭Atomic Pineapple


    zubair wrote: »
    Seeing as Donal is asking about the cat I'm sure he's talking about the exhaust and not a dv. Maybe the "booooow" was confusing.

    I've never heard an exhaust make anything like the sound the OP mentioned.


  • Registered Users, Registered Users 2 Posts: 2,459 ✭✭✭zubair


    I'm not going to discuss whether the "boooooow" is dv or exhaust. Donal needs confirm if he wants real help.


  • Registered Users, Registered Users 2 Posts: 37 Donal199


    The 'boooww' sound is made from the turbo spool, when changing gear or slowing down, it can be heard in some turbo diesels, i just wanted to know if this noise could be heard more clearly if the cat is removed. Its not a dv im not talking about.


  • Registered Users, Registered Users 2 Posts: 18,272 ✭✭✭✭Atomic Pineapple


    Donal199 wrote: »
    The 'boooww' sound is made from the turbo spool, when changing gear or slowing down, it can be heard in some turbo diesels, i just wanted to know if this noise could be heard more clearly if the cat is removed. Its not a dv im not talking about.

    No, removing the cat will only increase the noise from your exhaust


  • Closed Accounts Posts: 10,833 ✭✭✭✭Armin_Tamzarian


    I'm still confused.
    It sounds like you're talking about the wastegate which can be adjusted though I wouldn't.
    End of the day mate it's a diesel, no matter what you do it won't sound good.


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  • Registered Users, Registered Users 2 Posts: 2,459 ✭✭✭zubair


    I'm still confused.

    Me too!!!!


  • Registered Users, Registered Users 2 Posts: 9,727 ✭✭✭Midnight_EG


    Draff, my exhaust makes the booooowwwww :o




  • Registered Users, Registered Users 2 Posts: 805 ✭✭✭metzengerstein


    it usually adds more of a deeper growl ,rather than that awful thiny boy racer sound

    i really despise that dump valve noise that someone mentioned above sounds stupid ,ive seen some big moded cars with it and it just ruins it makes them sound whimpy


  • Closed Accounts Posts: 10,833 ✭✭✭✭Armin_Tamzarian


    i really despise that dump valve noise that someone mentioned above sounds stupid ,ive seen some big moded cars with it and it just ruins it makes them sound whimpy

    I love the sound off a BOV.
    Obviously not on a diesel though.


  • Registered Users, Registered Users 2 Posts: 8,620 ✭✭✭Graham_B18C


    On a proper high pressure turbo it sounds cool, like an Evo, Impreza or Supra


  • Registered Users, Registered Users 2 Posts: 420 ✭✭Diageio_Man


    Meaooo!!!


  • Registered Users, Registered Users 2 Posts: 1,148 ✭✭✭okane1


    draffodx wrote: »
    No, removing the cat will only increase the noise from your exhaust


    Wrong, nothing to do with the noise from the exhaust. With the decat the car has a much better throttle reponse as the restriction in the exhaust system isn't there anymore. The turbo is able to spin up to speed a bit quicker. You can also hear the turbo spooling up and down giving the noise the OP described (badly!)

    I fitted one to my mondeo st tdci and has made a massive difference. If your getting one, make sure the bore of the decat is the same diameter or large than your exhaust, to ensure it doesnt cause a restriction.


  • Registered Users, Registered Users 2 Posts: 18,272 ✭✭✭✭Atomic Pineapple


    okane1 wrote: »
    Wrong, nothing to do with the noise from the exhaust. With the decat the car has a much better throttle reponse as the restriction in the exhaust system isn't there anymore. The turbo is able to spin up to speed a bit quicker. You can also hear the turbo spooling up and down giving the noise the OP described (badly!)

    I fitted one to my mondeo st tdci and has made a massive difference. If your getting one, make sure the bore of the decat is the same diameter or large than your exhaust, to ensure it doesnt cause a restriction.

    I was referring only to removing the cat in the context of noise, of course removing a cat increases performance, however the OP never asked about that.

    Removing the cat will not give the OP the atmospheric dump valve type noise that they appear to be describing and it will make the noise coming from your exhaust louder.


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