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sports cat or decat?

hydro s3 Apr 15, 2017

  1. hydro s3

    hydro s3 S3 amk Team Ming Blue Audi S3

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    I have been gathering parts for a engine rebuild and it has come now to think of exhaust. Im getting a 3" downpipe and 3" from cat back. Not sure as to put on a 200 cell sports cat or just decat it. I dont want to have to change it over when it needs it's mot. What performance gains is the difference between the two?
    Thanks
     
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  3. Lavis89

    Lavis89 Well-Known Member Regional Rep Team Sprint Audi S4 Audi A3

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    If you can find someone that will MOT your car without a cat then you might as well go for a decat, if that's a issue then stick a sports cat on.
     
  4. superkarl

    superkarl MAN OF STEEL

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    So you want a cat then.
    Performance will be negligible with a good cat. May dampen the sound a little too, in a good way.
     
  5. Solberg

    Solberg Active Member

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    I am buying the downpipe from zinram so its easy to change from cat to decat with vbands before mot.

    I went from decat to 3" ebay downpipe with 200 cell last year and that thing made my exhaust go from spitting flames and making bangs on gear changes, to become completely silent, thats a big downer if you ask me. So that cat is coming off very soon, and on again for 1 day when i have it for mot later this year, and then straight off again.
     
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  6. Tj 0785

    Tj 0785 Well-Known Member Silver Supporter VCDS Map User Bronze Supporter Audi S3

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    Are the cheap eBay downpipe and cats much more restrictive than a pipewerk one? Or a decat
     
  7. superkarl

    superkarl MAN OF STEEL

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    I've never physically compared to two.
    Essentially any cats labelled '200 cell' should be the same.
    But I would trust the pipeworx to be of better quality than say a relentless/xspower


    Sent from my iPhone using Tapatalk
     
  8. hendo#1

    hendo#1 Active Member

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    Find a friendly MOT tester and go de-cat. Made a huge difference to my car.

    Honestly, learn from the many people that have already tried it on here, do not go for a cheap down pipe. Get a quality down pipe and de-cat, such as the pipewerx one. It really isn't a job you want to be doing twice.
     
  9. Tj 0785

    Tj 0785 Well-Known Member Silver Supporter VCDS Map User Bronze Supporter Audi S3

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    I thought it was just manifolds people had problems with not read off any horror stories about the downpipe
     
  10. vivalacoulter

    vivalacoulter Active Member Audi S5

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    Personally I could never be bothered changing in and out cats so I just left the 200cell someone had already put on it in place. Even that had trouble on emission tests if they didn't do it straight away when I got there with the engine hot.

    And, you know... The environment! :evergreen::herb::tropicalfish: haha.
     
  11. hydro s3

    hydro s3 S3 amk Team Ming Blue Audi S3

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    I live in Northern Ireland so we have government mot center's we have to use thats why id have to change the decat out each time for the mot.
     
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  13. hydro s3

    hydro s3 S3 amk Team Ming Blue Audi S3

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    Its not that i want one. If i get the same benifits from a sports cat v decat apart from noise im not intrested in that. Its just changing it over each time
     
  14. <tuffty/>

    <tuffty/> Badger 5 Edition...Its all about the flow... Staff Member Moderator Audi S3

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    At your power level I doubt you would notice anything between the two... A decat would help spool a little and keep egts a bit lower but would depend on your use (or abuse) and setup... If a road car with the occasional blast then cat... If you track the car then a decat and swap it for road/mot

    <tuffty/>
     
  15. hydro s3

    hydro s3 S3 amk Team Ming Blue Audi S3

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    Sports cat it is then as its my daily driver and not thinking of going near a track in it.
     
  16. Solberg

    Solberg Active Member

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    This thread inspired me to go out in the garage. Was impossible to hallow it like i foresaw, so had to cut the cat in pices, hammer the tinanium out and weld it back together.

    Not sure if car spools sooner, but it pulls so much harder that the car was notibly scary to drive after removing the inside of the team2fast ebay 200 cell cat. It was very restrictive thats for sure.

    [​IMG][​IMG][​IMG][​IMG][​IMG][​IMG][​IMG][​IMG]

    Sent fra min SM-G925F via Tapatalk
     
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  17. hydro s3

    hydro s3 S3 amk Team Ming Blue Audi S3

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    Now i dont know what to do. That last post seems better not to have a cat. My end goal is high 300bhp and these are the parts i have been getting over the last couple of months to get close as possible to that figure. On the exhaust parts at the min. Was looking at a pipewrex 3" downpipe and there sports cat but if there that restrictive mybe just go decat and just get it changed for mot. Some thing else now ill have to think of what way to go.
     
  18. Solberg

    Solberg Active Member

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    I am not to come say cats is shitt, just sharing the experience I had, something to point out is that the xpensive ones ive seen have had some size but the ebay ones is pretty "small". If i were to use my car as a dailydriver stock´ish car, I would probably just let a cat stay on and thats it.

    But runnning high boost, and taking it to a couple trackdays a year I dont want that on my car. But I will later on need a cat for mot, so thats why I am buying the Zinram one. It comes with a cat, but I thought to just take a 3" pipe with same length as the one with the cat, put a vband on it and smock super easy to change between cat/catless.

    http://www.fahrzeugtechnik-zinram.d...ctPath=/Shops/61798191/Products/DP76TTS38L200

    [​IMG]
     
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  19. Tj 0785

    Tj 0785 Well-Known Member Silver Supporter VCDS Map User Bronze Supporter Audi S3

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    What t turbo you going for?
     
  20. superkarl

    superkarl MAN OF STEEL

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    The nice thing about that Zinram one is it doesn't taper down to stock 2.5 inch exhaust size at the end. Which is what others do, in order to join a stock system, and rightly so.
    But I bet a 2.5 inch section in a 3 inch exhaust has as much impact as a sports cat on flow.
    Sports cat, clean 3 inch to the back of the car is most ideal for you guys who worry about mot time.
     
    hydro s3 likes this.
  21. hydro s3

    hydro s3 S3 amk Team Ming Blue Audi S3

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    I was looking at the k04 hybrid turbo package badger 5 has for sale
    I will have all internals changed and upgraded before that goes on so i should have a reliable engine to put something like that on. My options are open since im getting the rebuild done.
     
  22. hydro s3

    hydro s3 S3 amk Team Ming Blue Audi S3

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    Thanks superkarl that makes sense
     
  23. Mav190sline

    Mav190sline Active Member

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    I think I may have the team2fast sports cat on my car. Long story as to why (purchased new but second hand if you know what I mean, from a seller claiming to be a different make). After mapping was told the sports cat was "highly restrictive", and so I have to agree with solberg.
    Was thinking about purchasing a decat and swapping it out at mot time.
    After reading solbergs earlier post I now think I will
     
    Solberg likes this.
  24. hydro s3

    hydro s3 S3 amk Team Ming Blue Audi S3

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    If speaking from experience then i to will go decat and just have to put on a cat for the mot. Will the original cat fit so i can just keep that or do i need to buy a different one.
     
  25. Mav190sline

    Mav190sline Active Member

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    Original cats won't fit
     
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