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Decat Pipe - Noise Increase?

Toshers Jul 5, 2018

  1. Toshers

    Toshers Active Member Team Nardo TFSI Owners Group Audi RS3

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    What level of noise increase have people experienced fitting a decat pipe? I have the Audi sports exhaust which I will be keeping from the cat back but wondering what impact the decat will have? I still need the car to be sociable in the mornings lol
     
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  3. Leo-RS

    Leo-RS Well-Known Member

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    If the standard Sports Exhaust is 6, the decat takes that upto 10 on full throttle. It is loud, and it is loud on cold start.

    Under normal driving conditions in D and comfort, there's little to no difference. In dynamic part throttle it's maybe 8/10. In dynamic under full WOT, it's 10/10 loud, but in a nice way.

    You will unfortunately suffer more from the dreaded "WG rattle" that becomes very noticeable without a cat masking it.
     
    Toshers likes this.
  4. AudiNutta

    AudiNutta Well-Known Member Team Racing Blue Mica Audi RS3 quattro Sportback

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    Ah, so it’s not my exhaust valves rattling under load at low speed but the wastegate? Tappety noise
     
  5. Leo-RS

    Leo-RS Well-Known Member

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    If it’s the same noise as the cold start noise then it’s rumoured to be the turbo WG.

    You should know if it’s coming from in front of you or behind you though haha.
     
  6. Toshers

    Toshers Active Member Team Nardo TFSI Owners Group Audi RS3

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    I have to admit I haven't had the car long enough to experience the WG rattle!

    Surely it's possible to modify it out?
     
  7. D0C

    D0C Well-Known Member Team Nardo Team Panther Audi RS3 TTRS

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    I get the dreaded rattle, and it's definitely from the front of the car.
     
  8. cjm999

    cjm999 2017 RS3, Ara Blue Sportback

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    I haven't heard any sort of rattle in mine, and I'm really OCD with any kind of sounds like that (that passengers can never hear). Must be one of the lucky ones.
     
  9. Nickyc

    Nickyc Member

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    Is this for facelift ? I thought they didnt have 2ndary cats ? or are we referring to the main ones ?
     
  10. Leo-RS

    Leo-RS Well-Known Member

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    All facelift cars will sound terrible on cold start. The noise silences after about 45secs.

    In a decatted car, (main cat removal) the sound is present under part throttle conditions between around 20-70% throttle position. It’s the same type of rattle as you experience from the cold start.

    The sound is always there, even with the car completely standard, it’s just the main cat masks it under normal driving. Some people with good ears claim they can hear it even with a standard car.

    As far as I’m aware the only fix is by opting for a big turbo change, mapping apparently cannot stop it. It’s claimed to be from the wastegate but some are sceptical, it’s definitely in and around that area and definitely turbo related.
     
  11. Javbomb

    Javbomb Member

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    I dunno, not in all cases, I get the same rattle during driving if the car is in comfort mode (flaps closed) and under part throttle at speed. I can make the sound completely vanish by changing to dynamic and opening the flaps.

    So, I think when some people talk about this, they legit still have valve rattle from the rear under driving conditions.

    I'm tempted to open my valve boxes and put springs in there so there is some tension on the valves. I can completely stop the rattle if I am on the ground and put my finger lightly on the valve pivot pin on the back of the exhaust. There was a brief youtube video floating around somewhere showing some guy putting a spring in there, I think it was Italian or some such.
     
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  13. AudiNutta

    AudiNutta Well-Known Member Team Racing Blue Mica Audi RS3 quattro Sportback

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    It sounds like the middle of the car, like the cold start rattle.
     
  14. T-800

    T-800 Well-Known Member Team Glacier TFSI Owners Group VCDS Map User Audi RS3 quattro Sportback S tronic MQB Platform

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    When you start the car in the morning and put it in dynamic to stop the rattle noise look at the boost gauge.......you'll see the minute you put it into dynamic its's building a small amount of boost, the minute the rattle stops at 20 secs or so the boost reading stops.
     
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  15. Toshers

    Toshers Active Member Team Nardo TFSI Owners Group Audi RS3

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    Ordered a Milltek decat down pipe :rockwoot:
     
  16. JamesCrs3

    JamesCrs3 Active Member

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    Decat life!
     
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  17. Slowracer

    Slowracer Active Member

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    Personally I find the the exhaust to be loud enough for me. Every time I open the exhaust and give it some juice, I notice that heads on the street turn.

    I actually prefer to be a little more stealth when being a little naughty on the road.

    But granted I wouldn't mind a bit of a burble at low range engine speeds when ambling along. But I don't mind the lamboesque moan it has a low revs, it's rather unique.
     
  18. Oli.

    Oli. Active Member

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    PFL and added the secondary de-cat pipes with the Sporst exhaust. As has been said cold start is louder than ever - shame this cant be coded out. Normal driving in comfort, very little difference, but in dynamic, sound like the devil is under the bonnet, just sound epic! Get some really loud pops and bangs, and the noise under full throttle is nothing short of ‘mini supercar’!
     
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  19. penetrator

    penetrator Well-Known Member

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    I’m having a Rogue Performance Decat Fitted on my FL tomorrow, the Sports Exhaust has already been de-resonated, and had the backbox made straight through and the sound deadening material removed so it should sound epic
     
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  20. Toshers

    Toshers Active Member Team Nardo TFSI Owners Group Audi RS3

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    You have big kahoonas or very tolerant neighbours! Would be too loud for me I think. Would still like to see and hear a video clip mind you...
     
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  21. FBF01

    FBF01 Well-Known Member

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    So you’ve made it as loud as humanly possible lol? Brilliant
     
  22. penetrator

    penetrator Well-Known Member

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    This will still be quieter than the M3 but the 5 pot is such a nicer sound. I’ll try and get some clips ASAP
     
  23. penetrator

    penetrator Well-Known Member

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    Absolutely mate :icon thumright: there’s no other way.
     
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  24. penetrator

    penetrator Well-Known Member

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  25. Marshy

    Marshy Settled in Team Sepang Audi RS3

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    Not a fan of the M3 exhaust sound
    Sounds really hollow and not a patch on the RS3
     
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  26. penetrator

    penetrator Well-Known Member

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    I agree it’s not as nice, Infact nowhere near as nice as the RS3 but it grows on you
     
  27. Rayner_1704

    Rayner_1704 DAN

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    Mine is standard down pipe secondary decat and rs back box
    Comfort is fine and quiet in the cabin and just normal volume of the rs on the outside
    Dynamic is boarderline asbo sometimes! Sometimes it seems louder then other times

    Start up is fine but can be a little awkward at 5 in the morning as it is super loud
     
  28. billymc92

    billymc92 2018 Ara Blue Facelift RS3

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    Click arrow to swipe along to see all 3 videos
     
  29. penetrator

    penetrator Well-Known Member

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    So yesterday I went to get my Decat fitted at CLP Automotive in Sheffield, great place with some good lads. After sitting in there restroom for over 2hrs one of the lads came out to me with the glorious news that.....it doesn’t fit!!!
    I initially laughed thinking he was joking, however he fooking wasn’t. I went and had a look for myself and there was about 1.5” gap from the fitted downpipe to the mid section.
    The guys tried several things to get this to fit however you can’t just disappear that gap so it had to come off and the lad had to put everyth8 g back to normal. At this point I was absolutely bloody raging as I had purchased a Decat for my spec car and it didn’t fit, also I had to still pay for labour, so the phone calls commenced to the supplier...

    So to cut this collamity short, the supplier of the Decat held there hands up and said there’s probably been a mix up with the pairing of downpipe and midsection as there numbered as a pair from the manufacturer etc. So the labour cost was paid by the supplier who passed that on to manufacture etc, I spent 6hrs at clp with no end product apart from having the transmission dogbone insert fitted. I was supposed to have my springs fitted too but obviously that didn’t happen!!

    Going forward the supplier has offered to fit the DP and springs for free as they’ve got a new one on its way to them, caveat being I have to take my car to Scotland lol
     
  30. cjm999

    cjm999 2017 RS3, Ara Blue Sportback

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    Nightmare mate! What brand of downpipe was it? What was your aim with having it fitted at the moment, not sure Revo have the stage 2 map out yet?
     
  31. Toshers

    Toshers Active Member Team Nardo TFSI Owners Group Audi RS3

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    Stage 2 isn't out yet but they do have a pipe file for stage 1 (1+) available that will eliminate the decat fault code.
     
    Seanix and penetrator like this.
  32. penetrator

    penetrator Well-Known Member

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    Rogue Performance from South Africa, it’s a quality bit of kit which makes it more frustrating
     
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  34. penetrator

    penetrator Well-Known Member

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    Revo stage1+ once it’s on.
     

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