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Exhaust pop

Discussion in 'A3/S3 Forum (8L Chassis)' started by dannyh, Jul 6, 2009.

  1. dannyh
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    dannyh Nogaro S3

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    [Jul 6, 2009]
    hello, i am going to get a A3 1.8T

    My mate has a astra vxr and he has put an exhaust on it and when he floors it and changes gear it pops

    if i had the 1.8T and put a cat back on it would it pop ar would i need more of a system?????
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  3. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User

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    [Jul 6, 2009]
    I can't imagine why would you want it to do that? As it would deliberatly draw attention to you

    Anyway, if you removed the cat as well you would be more likely to get the result you are looking for so Turbo back and catless FTW
    #2
  4. dannyh
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    dannyh Nogaro S3

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    [Jul 6, 2009]
    what is a turbo back exhaust and what about the manifold
    #3
  5. MintyS3
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    MintyS3 Works 60% the time, Everytime.

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    [Jul 6, 2009]
    It means the exhaust starts at the turbo all the way to the exhaust tip. Most people will get a cat back or perhaps get the sports cats or decat to compliment the cat back.

    This thread sounds like something I would of created when I was 16 and looking to buy a Nova...
    #4
  6. dannyh
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    dannyh Nogaro S3

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    [Jul 6, 2009]
    what do you mean????

    so does the exhaust normally come from the turbo, i am not use to the whole turbo thing?????
    #5
  7. mat20vt
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    mat20vt Member

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    [Jul 6, 2009]
    your turbo feeds into the downpipe, then cat, then into exhaust (cat back) then into rear box.

    mine pops a lot with a miltek exhaust and very large cat, and big turbo kit
    #6
  8. dannyh
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    dannyh Nogaro S3

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    [Jul 6, 2009]
    cheers mate so if you got a turbo back exhaust that would encorparat a part that connected to your manifold

    so unless i spent a fortune it wouldnt Pop?????
    #7
  9. mat20vt
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    mat20vt Member

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    [Jul 6, 2009]
    turbo back should be the downpipe, cat and cat back system.

    my old jetex system used to pop now and again.

    not something i'd buy an exhaust for tho, unless i was 17
    #8
  10. voorhees
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    voorhees Moderator Staff Member Moderator

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    [Jul 6, 2009]
    have a balloon and a pin in the car to gain the desired effect without paying out.
    #9
  11. dannyh
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    dannyh Nogaro S3

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    [Jul 6, 2009]

    I just think it sounds good thats all lol
    #10
  12. ChriS3
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    ChriS3 hud at ye bam

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    [Jul 6, 2009]
    A far less chavvy solution!


    If you want a pop, decat!
    #11
  13. dannyh
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    dannyh Nogaro S3

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    [Jul 6, 2009]
    ye but if you decat its an MOT fail so i wont be doing that lol
    ill probably put a dumpvalve on it,

    also what is the best airfilter to get and what make,
    is a cone best or and enclosed cone, whats best guys
    #12
  14. ChriS3
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    ChriS3 hud at ye bam

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    [Jul 6, 2009]
    200 cell sports cats do the same thing but come with a bigger price tag.

    You'll need a diverter valve, not a dump valve. If you dump you boost you'll confuse the ECU. Keep away from cone filters - too much hot air in the engine bay.
    #13
  15. A3Tom
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    A3Tom Smell my finger.

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    [Jul 6, 2009]
    My exhaust pops sometimes on gear changes, its like a muffled pop but it does it every now and then...mainly when under load etc.

    Doesnt sound too bad, I can put up with it every now and then and it only does it when I really give it the beans.

    I wouldnt want it to be any louder or happen more often though.
    #14
  16. mat20vt
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    mat20vt Member

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    [Jul 6, 2009]
    hmmmm mine sounds like a shotgun going off at times:ohmy:

    100cell cat on mine
    #15
  17. Bignick
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    Bignick Member

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    [Jul 6, 2009]
    Is'nt it caused by un-burnt fuel in the exhaust?
    #16
  18. A3Tom
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    A3Tom Smell my finger.

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    [Jul 6, 2009]
    Yep.

    Can happen on overun too, but I've not heard it do that on mine.


    A mini cooper I had years ago was great for it. Boot it all the way through the rev range in any gear and then take your foot off the gas and it would go BANG B B B BANG BANG......POP:lmfao:

    Used to really piss my neighbours off as it used to set most of the car alarms off in the street :p

    T
    #17
  19. marcyp
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    marcyp Only me

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    [Jul 7, 2009]
    my saxo vtr turbo useto pop bang and spit flames was a good fun toy, untill i blow the bottem end out, o well all i can say is its french was gonna happen sum time!
    but now having the audi there not realy cars that suit poping and banging as you go down the road, the steath silent attack is better imo but each to there own, if u realy wonted that sound a 3" turbo back system will give you that with a decat and single box system not sure if there any around like this thow?
    #18
  20. glen_jai
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    glen_jai Member

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    [Jul 7, 2009]
    Yes, I'll second that.
    When I only had a supersprint exhaust (cat back), it rarely pops.
    Now with a sports cat, I get the backfire pop all the time under full acceleration.

    Don't really understand the physics, as I always thought it was unburnt gases that makes that noise in the pipes. So not sure why having a sports cat would promote that.

    It does sound boyracer... but I also quite like it.:laugh:
    #19
  21. gadgesxi
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    gadgesxi Member

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    [Jul 7, 2009]
    I've owned both a corsa vxr and astra vxr and both pop and bang on gear changes. Only once you have a proper exhaust put in with a 100 or 200 cell cat. Corsa had a milltek full system and astra had a remus full system. Both with precats removed.

    They pop because on WOT (wide open throttle) the cylinders/pistons are cooled by fuel and the result is that unburnt fuel goes through the exhaust, ignites with the high temp and pops!

    Great cars IMO. Unfortunately you cant fit two big Ridgebacks in the back of them!
    Last edited: Jul 7, 2009
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  22. voorhees
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    voorhees Moderator Staff Member Moderator

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    [Jul 7, 2009]
    Totally off on tangent from the topic but you are talking about Rhodesian Ridgebacks aren't you ?
    #21
  23. gadgesxi
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    gadgesxi Member

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    [Jul 7, 2009]
    yep:)
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  24. subby
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    subby Member

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    [Jul 7, 2009]
    get a ford racing puma, then you'll get pops!

    Had the engine and exhaust in my old mk4 fiesta. Sounded amazing.
    #23
  25. 666markyboy
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    666markyboy Well-Known Member

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    [Jul 7, 2009]
    What ??? is this some sort of reverse technology ecconomy thing ??? surely any fuel in the cylinders gets burned unless it's running incredibly rich.... i've heard of oil being squirted to the underside of pistons to cool them but never Fuel :undwech:
    #24
  26. gadgesxi
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    gadgesxi Member

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    [Jul 7, 2009]
    yep, they all run rich
    #25
  27. ChriS3
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    ChriS3 hud at ye bam

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    [Jul 7, 2009]

    I had a cat back Supersprint, 200cell sports cats, and a big turbo (very similar set-up to yours?). Loads of popping, and if you feathered the throttle on the over run, it would go off like a tommy gun. It's fun to scare pedestrians as you drive/bang past.

    I was having a chat with Jim from Star Perf about it. He thinks its helped by the stainless exhaust, and less silencing in the cat.
    #26
  28. A3Tom
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    A3Tom Smell my finger.

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    [Jul 7, 2009]
    Especially after a map,....hence why rally cars pop, bang, crackle and fart their way around.
    #27
  29. dannyh
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    dannyh Nogaro S3

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    [Jul 7, 2009]

    ha ha ye:laugh::laugh:

    right now i undersand now that if i get a downpipe, 200 cell sport cat, mid pipe and back box then when i put my foot down it will pop/bang

    good got it lol

    now what is this about not putting a dump valve on it, what is the purpose of one and what should i use insted and will it make the same noise??????
    #28
  30. A3Tom
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    A3Tom Smell my finger.

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    [Jul 7, 2009]
    Due to how the 1.8T engine works etc you have to have a recirculating one. A 'dump valve' dumps the air to atmosphere, the 1.8T needs one that recirculates it.

    You do get a bit of noise but not much. I can hear mine but thats due to a Forge TIP and a remap (more boost). You can however fit an induction kit that will give you the noise of the valve a bit more.
    #29
  31. ChriS3
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    ChriS3 hud at ye bam

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    [Jul 7, 2009]
    A diverter valve sounds more like Darth Vader with a cough.
    #30
  32. dannyh
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    dannyh Nogaro S3

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    [Jul 7, 2009]
    whats a Forge TIP

    and ill be getting an enclosed airfilter, can you recomend a good sounding and good make airfilter
    #31
  33. Nilz
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    Nilz Defo worth the wait :)

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    [Jul 7, 2009]
    Green cotton air filter
    #32
  34. A3Tom
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    A3Tom Smell my finger.

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    [Jul 8, 2009]
    TIP is the turbo intake pipe, the pipe between the airbox and the turbo :)
    #33
  35. Ess_Three
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    Ess_Three Active Member

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    [Jul 8, 2009]
    Rally cars popping and banking is so far removed from road cars, it's scarcely worth considering.
    Anti-lag is the usual cause of the popping...and you really don't want that unless you fancy changing your turbo weekly.

    Competition cars are set up to make big power under full load. That's it...off load mapping is all about protecting the engine and getting fuel ready for next time it's on load...so they often run rough as hell (big turbos, big cams, anti-lag) in everything but full power.

    Not the same as after a remap on an A3!
    #34
  36. Ess_Three
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    Ess_Three Active Member

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    [Jul 8, 2009]
    No it won't...
    If the engine is mapped properly, you'll get no more popping and banging than standard...except maybe the banging of an ill-designed and made exhaust banging about.

    If your car pops and bangs when you put your foot down, it's broken. End of.


    A dump valve dumps the air to atmosphere.
    Metered air, the ECU knows is in the system...

    If you dump it to atmosphere, the ECU gets confused, has to re-meter the air and you add delays on getting the power back when you put your foot down next.
    In effect, fitting a DUMP valve to a 1.8T is loosing you power...or de-tuning.
    But I'm sure it sounds 'ace'. Innit.

    You want a DIVERTOR valve which dumps the air back into the inlet, so the engine doesn't have to suck it back through the air filter all over again...

    If you want the silly low-rent Chavvy 'tchhh' noise, then it will cost you response and power. And in my opinion sound ****.
    #35
  37. S3Alex
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    S3Alex Rarely neutral

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    [Jul 8, 2009]
    Very true....my last properly fast car was an ex GpN Escort Cosworth,with anti-lag and water injection plus all of the other racing alterations(straight cut gears,Quaife diffs etc),and whilst the mapping was good enough to allow smooth running even at idle,and in traffic,it would still spit flames and bang on overrun,and with the ALS on,it was undriveable at less than full throttle.

    Having said that,it was totally reliable and pretty nearly unbreakable for road use,but thirsty and unbelievably noisy.
    Another point is that building and running an engine that will run that sort of power reliably(see that comment below about blowing the bottom of the engine out for instance) is extremely expensive.

    Hence an S3.

    You can make a good road car sound like a race car,but quite honestly it will never get close,and often as Ess_Three has said,all that stuff makes the car slower,less driveable and it still isn't a race car...at all.
    Last edited: Jul 8, 2009
    #36
  38. Ess_Three
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    Ess_Three Active Member

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    [Jul 8, 2009]
    So true... :icon_thumright:


    But if it says 'Race' on the advertising, it must be good, eh?

    'Race' dampers = hard as hell, not weather protected...so will ruin the handling on the rioad and leak in months.
    'Race' callipers = no dirt shielding so will seize up at the first sign of winter.
    'Race' cams = nothing below 6000RPM...just what you need on the road!
    #37
  39. JayA4Turbo
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    JayA4Turbo Member

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    [Jul 8, 2009]
    Haha, exactly! I have the APR R1 valve on my A3 with a TTDA and you can't even hear it. . . .exactly how I want it!
    Last edited: Jul 8, 2009
    #38
  40. dannyh
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    dannyh Nogaro S3

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    [Jul 8, 2009]

    wooooow to much slang being used here, i'm a newbie, and dont know what you are taklking about, the world of turbos is all new to me and i dont know what they are or how they work or what products are best for them lol

    all i know is i want it to sound sporty and go quicker than standard
    #39
  41. S3Alex
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    S3Alex Rarely neutral

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    [Jul 8, 2009]
    Again,all true....if it says "race" anywhere on the packaging it must be good.

    So much race technology isn't in the least bit suited to road use,and a lot of consumer oriented stuff that says "race" on it,bears as much resemblance to racing as all those chavved up "cars" do to rockets.

    The OP would do much better to get a decent aftermarket exhaust,have the boost upped to a safe and useable level,and forget about how it all sounds.

    Mine doesn't pop or bang,but it is a lot faster than a standard S3.
    #40

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