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Thread: Sound from the air filter

  
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    Sound from the air filter

    I fitted Bailey DV26-D dump valve to my turbo coupe.


    But, now when I´m driving, and if I back off throttle (change gears) under 3500 rpm, I can hear a sound comeing from my K&N Apollo kit, the sound like the DV isn´t opening and a part of the air is going back to the turbo. I can hear the DV sound from my Bailey DV, but it isn´t as loud as it is if I rev the car higher, over the aprox. 3500 rpm.
    The sound that I get from the Apollo kit is the same that I got when my OE dump valve was broke and wasn´t working properly.
    Is this normal or what? I´m running stage 1 remap, with 0,8 bar boost, and 1.0 bar overboost.
    Astra Coupé Turbo Z20LET GT28RS

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    Sounds to me like a little wastegate chatter

    How comes you have a VW sign on your Opel cover ???

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    Quote Originally Posted by LordNikon View Post
    How comes you have a VW sign on your Opel cover ???
    You have to read the whole sign...




    btw: what causes this sound, the wastegate chatter?
    Astra Coupé Turbo Z20LET GT28RS

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    LMAO, that was a good answer, i too was a little curious as to why there was an VW sign on it.

    I wouldnt worry about it pal, it seems that the K&N makes this noise, it is a bit strange but a pal of mine has just a K&N on his and this makes the noise too, as does mine.

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    stevenet15's Avatar
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    its probably the turbo chattering as aftermarket dumpvalves dont work great on the zlet and thus causes the turbo to chatter a little. its realy bad for the turbo and will cause the turbo life time to decrease
    Astra Coupe Turbo

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    I also had a Bailleys DV and also had a K&N 57i kit on my old sri turbo as well, so...

    Yep, deffo turbo stall. On really high boost applications this has caused the shaft to bend (eek!) or even worse, the turbine wheel to shatter (double ek!)

    On low boost applications, it's just more likely to wear the bearings quicker. your best bet is to reconnect the original dump valve, even though it sounds (in my opinion, really quite cool!)

    When you say that it doesn't sound as loud below 3,500 than above, is this when driving or just revving stood still?
    2006 Astra VXR on 19's in Arden Blue
    ExhaustsUK Catback, Eibach Sportlines, DS Ultima, Roose hose kit, Forge recirculating dump valve, Full self modded SMD conversion

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    Quote Originally Posted by Gnasher View Post
    When you say that it doesn't sound as loud below 3,500 than above, is this when driving or just revving stood still?
    It is the same, there isn´t a big difference in driving or revving standing still... When the boost ih high, it opens as it should, but on lower levels of boost, some of the air goes through the DV, but some of it returns to the turbo...


    I know that some of the aftermarket dump valves don´t work so fine with the zlet, but this is Bailey DV-26-D... and everybody says that it is the best DV for the zlet...

    btw: when I had the OE airbox and K&N panel filter, I couldn´t hear this noise...
    Astra Coupé Turbo Z20LET GT28RS

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    so basically if you have the chattering noise then you should reconnect the OE DV..... Is that right??

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    The funny thing is that you won´t hear that nosie unless you have an "open" air filter.. such as K&N Apollo, or i57 kit...
    Astra Coupé Turbo Z20LET GT28RS

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    This is a short recording of the Bailey in action... hope you will be able to hear the noise when I don´t rev the car so high...



    http://www.youtube.com/watch?v=fswTaXaQ31c
    Astra Coupé Turbo Z20LET GT28RS

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