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2.0TFSI Pre-Cat Removal

Discussion in 'A3/S3/Sportback (8P Chassis)' started by jb0o, Jan 25, 2012.

  1. jb0o
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    jb0o North East Forum Moderator Site Sponsor

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    Got a heads up of a good friend of mine over at Briskoda about the pre-cat removal that a fair few people have been doing to their TFSI.

    Removing the pre-cat will not affect your MOT, the pre-cat was fitted to aid in the cold-start emissions, which isn't tested in a UK MOT.

    Reported gains are:
    - Turbo spools up quicker
    - More Turbo Sound
    - Deeper Exhaust Sound
    - Reported increase in economy of around 5mpg!

    Looks like something you can do yourself quite easily given basic mechanical know-how and are good with a hammer and chisel :) think I'll do this when I get a bit of free time.


    I know my 1.6FSI was also fitted with a pre-cat but I'm not sure how it would affect these engines as the 2 threads I've read on Briskoda.net and mk5golfgti.co.uk were aimed solely at the 2.0TFSI AXX/BWA engine.

    Threads can be read here:
    Pre cat removed - BRISKODA.net - The Skoda Forum and Community
    Pre-cat. . . . . REMOVED!

    Thoughts anyone?
    #1
  2. RedDejavu
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    RedDejavu Well-Known Member

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    would the downpipe not remove the precat? Have no idea where it is fitted so dont kill me if I'm wrong:]
    #2
  3. Silky-S3
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    Silky-S3 Is loving his new 8V S3!

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    Whats the point of doing this? Surey you would just fit an aftermarket down pipe?
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  4. IceHanger
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    IceHanger Active Member

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    This was an old mod from my VX days, did improve throttle response nicely.
    A new down pipe should remove it, if it's like teh VX it's located just down from the manifold so it get hot and starts working after about 20secs from key on. Yup not needed on MOT at all as they test your car when it's warm, if it was from cold the main exhaust cat would take a lot longer to light off.
    Make sure you use some good drill bits and a slow rotation speed and drill round it and use a good crow bar to remove.
    Wonder if the S3's have this hmmmm cheap mod

    have fun!!!
    #4
  5. jb0o
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    jb0o North East Forum Moderator Site Sponsor

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    Sorry, forgot to mention the most important bit.. It costs nothing to do.
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  6. jb0o
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    jb0o North East Forum Moderator Site Sponsor

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    Yup but this is free to do ;)
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  7. pablo
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    pablo Member

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    thread revival but any issues with emmissions and engine management light doing this? Must admit Im tempted!
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  8. sliced
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    sliced Drive safe, stay alive.

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    Contacted my Local exhausts garage, they are gonna give me a quote tomorrow :D
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  9. nluk100
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    nluk100 Active Member

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    Emissions light will not come on. 5 MPG is un-realistic, but expect more top end power and quicker spool-up.
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  10. pablo
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    pablo Member

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    might give it a crack then :)
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  11. phil76
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    phil76 Active Member

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    Old trick with a good out come from what people say who have done it,plus the added bonus of shifting gasses a bit quicker ,people have quoted gains of 5-10 bhp which i cant see been correct but you never no,we were always on about doing a pre and post dyno run with it but too much of a pain in the ass,but said i was going to do this when i do my clutch while saving up for the proper exhaust.
    #11
  12. JJ.Foulds
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    JJ.Foulds Well-Known Member

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    And the news was...? :p
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  13. OliS3
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    OliS3 Member

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    I tired to do this on an S3 but with it being 4wd it is about 4 hours work rather than a few hours so decided against it. Shame as the results look good for just labour time.
    #13
  14. nluk100
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    nluk100 Active Member

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    Should be less than 2 hours by someone that knows what they are doing? Mine was done in less time than that.
    #14
  15. OliS3
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    OliS3 Member

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    Did they drop the sub frame to get at the downpipe?
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  16. nluk100
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    nluk100 Active Member

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    Not the subframe, but other smaller parts were removed / loosened to give better access to the turbo flange bolts.
    #16
  17. sliced
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    sliced Drive safe, stay alive.

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    that it was pointless and wouldn't add bhp...
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  18. nluk100
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    nluk100 Active Member

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    You have obviously never seen how dense the pre-cat material is? It adds bhp because it is another restriction the same as the main cat is. Not only that, but because it is right next to the turbo (hot-side) it causes a lot of back-pressure. The first thing you will notice when you do this mod is how early the turbo spins up. I'm not so sure you will notice 10 bhp but I saw 10-15ps on my car before I went to stage 1 (std car with just the pre-cat removed). Yes, you can get a new down pipe but have you seen how pricey they are?
    #18
  19. Granta
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    Granta Member

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    I did this a couple of weeks ago and definitely makes the exhaust note a bit louder. Power wise it seems to boost slightly earlier and a little quicker but not much different tbh. But for a free mod you can't go wrong.
    #19
  20. sliced
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    sliced Drive safe, stay alive.

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    That was the feedback given by the exhaust centre, no way can you get 10-15bhp from just a pre-cat delete, you get that gain from a full turboback exhaust system. I'd like to think they know what they are talking about, and I'm sure they have seen plenty of pre-cats...
    #20

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