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Down pipe and decat Vs Standard

Discussion in 'A3/S3 Forum (8L Chassis)' started by dannyh, Aug 2, 2010.

  1. dannyh

    dannyh Nogaro S3

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    Hi i currently have a cat back exhaust system that is quite loud ( Non resonated)

    I am thinkig of finishing off the system with a 2.5inch downpipe and decat. Will this make the car any faster and will it make it any louder, its already quite loud and i dont know if i want it any louder

    Would it be better to fit a sport cat, will this make it quicker and not as loud

    Cheers
     
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  3. Welly

    Welly VX220 SC Driver :)

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    And this is on what car?
     
  4. dannyh

    dannyh Nogaro S3

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    1.8 20v Turbo FWD
     
  5. Welly

    Welly VX220 SC Driver :)

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    Ahhh, OK cool. That makes things a little easier.

    Either go with the 2.5" or 3" downpipe and decat - both are MUCh less restrictive than the stock item which is quite frankly gash.

    Won't make much noise increase, but will allow the turbo to spool up much better as the gases flow MUCH easier.

    I had this one fitted on my A3: http://cgi.ebay.co.uk/VW-Golf-GTi-B...arts_Vehicles_CarParts_SM&hash=item20b2793b65

    It was great, well made and an absolutely bargain to be fair. Easy to fit as well.
     
  6. dannyh

    dannyh Nogaro S3

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    what kind of gains do you think a 2.5 inch downpipe without cat will give and would this be the same with a sports cat
     
  7. Welly

    Welly VX220 SC Driver :)

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    The cat is irrelevant to be honest, sports cats flow as well as no cat at all.

    It's not the cat that's restrictive as stock - it's just the downpipe.

    Hard to say what sort of gains, BHP will be negligible, but turbo spool up time will be greatly improved.
     
  8. dannyh

    dannyh Nogaro S3

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    and spool up time inproves 0-60 times?????
     
  9. Welly

    Welly VX220 SC Driver :)

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    Should do - will at least make a difference to acceleration....
     
  10. shanejess

    shanejess Guest

    shove your finger up your arse when your just about 2 fart, thats how your engine feels like with a cat. 3ich down pipe and de-cat is what you need, people who say the standard s3 cat is as free flowing as a de-cat live life with their finger up their arse, i hope this helps your decission.
     
  11. devan

    devan Member

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    But a cat will be needed to be fitted to pass an MoT right?
     
  12. djdougalno1

    djdougalno1 Member

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    Depends on where you get yor mot done I have no cat and my car passes the emisions test for an extra £10 aslong as everything else is ok and safe
     
  13. s3dave

    s3dave TFSI Hybrid
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    public forum........
     
  14. Dazboss

    Dazboss Like A Thristy Dingo ;)

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    Yeah true, dont want to loose your contact...
     
  15. Dazboss

    Dazboss Like A Thristy Dingo ;)

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    I've always gone de-cat tbf, but im not sure if i am going to. I dont even want to change the exhaust system.
     
  16. Welly

    Welly VX220 SC Driver :)

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    For openers, it's not an S3.... Which have 2 cats. The A3 has 1. And I said a SPORTS cat is as free flowing as a decat.
     
  17. dannyh

    dannyh Nogaro S3

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    any one with a video of the exhast sound with decat, i am thinking of getting 2.5 inch downpipe and decat then a silencer neer the back so it isnt any louder or is this pointless and will it cancel each other out
     
  18. dannyh

    dannyh Nogaro S3

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    any one with a video of the exhast sound with decat,
    i am thinking of getting 2.5 inch downpipe and decat but so it int any louder i want to get a silencer neer the back. Would this make it more restrictive and pointless and will it cancel each other out or would a silence/resonator neer the back before the backbox be restrictive
     
  19. devan

    devan Member

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    Ive been looking on the ebay page for the Audi S3 PipeWerx 3" downpipe and high flow cats, and it says the Dog Bone Mount must be uprated before fitting the exhaust, why is this please?
     
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  20. superkarl

    superkarl MAN OF STEEL

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    brilliant! :')
     
  21. dannyh

    dannyh Nogaro S3

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    sorry to keeosting the same think but i just want to know, will a silence/resonater be restrictive, if so how restrictive
     
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  23. finny_quattro

    finny_quattro Member

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    i have a twin cat on mine (1.8t quattro) im gona go for a custom 3 inch decat and down pipe..3 hundrea quid but the bloke at the exhaust place im taking it 2 said theres a law on cars after and before 2001...being you can get fined if its after 2001 but if its before the worst they can do is tell u to take it off...but if it passes their emissions test you are perfectly ok to drive with it on although the chances of it are canny slim! dont know if hes right but who knows? im going for one after he does my 2.5 inch cat back
     

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