Cat query

  1. Saxperience Forum Bum Joined: Apr 2013 Jarrow Posts: 4022 2003 Icelandic Grey 16v VTR 1991 Daihatsu GTti
    #1
    Before I start I'm not planning on doing this just wondered if it would have and benefits.

    I was at my mates garage today dropping off some cash I owed and one of the guys who works for him was knocking all the insides of a cat out.

    It was a diesel A4, I'm assuming that the guy he was doing it for wanted a straight through system so to speak.

    What would it do? I think not to much as it would be standard system minus the cat, but the exhaust gasses wouldn't flow properly.

    Can anyone shed any light I it for me?
  2. Saxperience Hardcore! Joined: Dec 2007 smurfland. Posts: 17346 Ex saxo owner.
    #2
    It won`t do a lot really,I mean it wouldn`t de-restrict the car that much,however if he got stopped it would still look like a standard exhaust system with a cat.Thus complying with the law.He`d probably fail an emmissions test though,was the guy wearing a mask when took the innards out?As theres some nasty stuff in those cats.
  3. Saxperience Forum Bum Joined: Apr 2013 Jarrow Posts: 4022 2003 Icelandic Grey 16v VTR 1991 Daihatsu GTti
    #3
    My mate said there was no point, but he says that about everything you could do to a car good or bad. He was masked up, that's what caught my eye and asked what was going on.
  4. Infrequent Poster Joined: Jul 2013 Aberdeen Posts: 130
    #4
    If its a turbo diesel then it will allow the turbo to spin up quicker.

    This will improve acceleration and he'll get slightly better mpg from doing it.

    He'd have been better with a proper decat pipe for performance but i guess if he was smashing the standard cat out either hes too tight to buy one or there might not be a decat pipe available for that car.

    A diesel will pass an MOT with no cat - either a smashed out standard one or a blatant aftermarket decat.

    They don't test emmissions on diesel mots - they only do a smoke test.

    You'll find you'll actaully get less smoke on a decatted diesel as, due to the increased flow, there will be less soot sitting in the system.
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  5. Established Member Joined: May 2012 West Yorkshire Posts: 1806 Civic EP2
    #5
    Dont forget the woosh noise when you let off change up my mates astra van sounded awesome for a derv with streight through.
  6. Saxperience Forum Bum Joined: Apr 2013 Jarrow Posts: 4022 2003 Icelandic Grey 16v VTR 1991 Daihatsu GTti
    #6
    Yeah it was a TDI, thanks for the info. I'm assuming that he wanted a bit performance without the cost and hasstle.