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Decat pipe

Discussion in 'A3/S3 Forum (8L Chassis)' started by Danny Cawsey, Mar 11, 2010.

  1. Danny Cawsey
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    Danny Cawsey Cawsey

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    [Mar 11, 2010]
    has anyone got a decat pipe on there exhaust?
    whats the gains and is it much lauder?
    #1
  2. OllieH
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    OllieH Member

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    [Mar 11, 2010]
    There are many threads on this already. The standard cats are not restictive, so a decat will not give any gains. I would say yes to making the exhaust slightly louder though. However, the downpipe is apparently restrictive, so changing this for a 3" item is better.

    Something like this:

    http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=300391095749&ssPageName=STRK:MEWAX:IT

    or this if you want a no hassle pass on MOT's:

    http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=300328725484&ssPageName=STRK:MEWAX:IT
    #2
  3. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Mar 11, 2010]
    I run a 200 cell CAT on mine with no issue...

    <tuffty/>
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  4. s3_stig
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    s3_stig Member

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    [Mar 11, 2010]
    I don't think there's anyreal gains from a decat on a s3 you would be better off changing the downpipe from what I have read someone will put you in the right direction tho
    #4
  5. tankie2ndrtr
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    tankie2ndrtr Member

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    [Mar 11, 2010]
    yeah been over it a few times.. previous owner fitted 200Cell ones on mine. Just passed an MOT fine, with debatable/no power gains..

    With no catts it will smoke more when cold :) and you have the drama of an MOT,
    #5
  6. s3dave
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    s3dave TFSI Hybrid Supporter

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    [Mar 11, 2010]
    ive got an 100 cell on mine and sailed through the mot... little more rumble though
    #6
  7. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Mar 11, 2010]
    I ran a decat when I first built up my 3" system but added the cat after a bit... didn't notice anything other than the exhaust was less boomy which is all good...

    Std exhaust system and downpipe is most restrictive... the EGT's on my car dropped from over 1100 degrees to around 950 degrees when I went from std to the 3"... putting the cat on made no difference to EGT's which would suggest it in itself didn't present a restriction to the flow... if it was that much of a restriction the EGT's would have risen a bit.

    3" DP, 200 cell cat and a decent free flowing exhaust will be as unrestrictive as you will ever need... should see spool kick in a tad earlier too

    <tuffty/>
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  8. s3gav
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    s3gav Member

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    [Mar 11, 2010]
    anyone used the pipewerx de cat and down pipe? im very tempted lol
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