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  1. #1
    VXRed
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    11th April 2016
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    23

    Default Sounds like a dump valve

    Hi Everyone!

    I got myself a Astra Vxr- 2013 last week.

    I need to ask you about what i think is a problem.

    I got this noise, like a dump valve or something similar when i let of the throttle, the car has no mods.

    It's only when i go over 2k 2,5k rpms( and higher) and let go of the throttle(prolly when the turbo kick in?). There's no such noise when the car i still and i rev it in neutral.

    Hope you get what i ment!

    Is it a problem or is it normal?

    Sorry for asking but i have no experience about the vxr yet!

    Thanks for any help i could get!

  2. #2
    VXRed Mjrsharpe's Avatar
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    8th February 2016
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    151

    Default

    The blow off valve on the Astra is the recirculating kind rather than an atmospheric dump valve. I can't hear mine when I come off the throttle. It's not turbo surge / flutter ? Could be a torn diaphragm on the factory diverter valve?

  3. #3
    VXRed
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    11th April 2016
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    Default

    Thanks for the reply!

    Hm not sure actuelly, but to me it sounds just like a dump when i let go of the throttle, maybe like a turkey noise. Not too loud either but it's definetly something that i hear every time. Do you think it's ok to drive? I have a service coming up on monday, i showed the serviceman and made him drive the car, he said they never serviced one before at that dealership but they had one in the shop on display, he said i could drive it(it goes well despite the noise but im unsure). Do you have any suggestions on what i should ask them to look at, other than the dumping sound?

    Thanks again for all the help i can get!

  4. #4
    VXRed blooded GTC_VXR's Avatar
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    18th July 2015
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    Default

    I get this on mine (2015), always made the noise since I got it brand new. Don't think it's something you need to worry about bud.

    James.
    James
    Custom 2015 Summit White GTC VXR


  5. #5
    VXR enough John w's Avatar
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    5th January 2014
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    1,533

    Default

    Quote Originally Posted by Norhidem View Post
    Thanks for the reply!

    Hm not sure actuelly, but to me it sounds just like a dump when i let go of the throttle, maybe like a turkey noise. Not too loud either but it's definetly something that i hear every time. Do you think it's ok to drive? I have a service coming up on monday, i showed the serviceman and made him drive the car, he said they never serviced one before at that dealership but they had one in the shop on display, he said i could drive it(it goes well despite the noise but im unsure). Do you have any suggestions on what i should ask them to look at, other than the dumping sound?

    Thanks again for all the help i can get!
    If it sounds like a turkey lol then I would get the recirculation valve checked as I've seen this before on the forum and it has been the recirculation diaphragm that's got a split in it in most cases.

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  6. #6
    VXRed
    Join Date
    13th October 2014
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    243

    Default

    Have never had this noise on mine since new, the recirc valve is the yellow/orange plastic item on the right of the photo of a turbo at,

    http://shop.wgmotorworks.co.uk/image..._n-500x500.jpg

    worth checking the rubber pipe to the centre of the valve isn't split/worn through anywere and hasn't come off at either the recirc valve or solenoid valve end, otherwise diaphragm in the valve needs checking out as already mentioned.

    For bypass (recirc) valve vacuum pipework info, see thread at,

    http://www.vxronline.co.uk/forum/sho...ation-diagram&

    There is a description of the purpose of the pneumatic over-run/bypass/recirc valve at,

    http://media.gm.com/media/gb/en/vaux...RESS_PACK.html

    where it says,

    'Further important features to this compact turbocharger include the pneumatic over-run air valve and an efficiency-optimised turbine wheel. At a defined vacuum, a valve is opened which leads the air back to the compressor inlet. This keeps the speed of the charger at a high level. When the accelerator pedal is pressed again, charge pressure is then immediately available.'

    If the recirc valve is not opening correctly immediately on releasing the accelerator, then the compressor will start churning the air and slow down, so that less boost pressure will be immediately available on pressing the throttle again.
    Last edited by Carbon Flash; 12th April 2016 at 01:11 PM. Reason: typo + additional info

  7. #7
    VXRed
    Join Date
    11th April 2016
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    23

    Default

    Thanks for all the replys.

    I will use the information you guys have given me when i service the car on monday, hopefully it's nothing special.

    I would just like to add a link of another car with the exact sound my car is doing: https://www.youtube.com/watch?v=Iybw9kbYUoA

    As said before, the car has no mods, so the sound should not be made( i think?).

    Could you guys help me out on other things i should ask the serviceman to inspect, since i still got ''used car warranty'' from the dealer.

    Thanks in advance!

  8. #8
    VXRed
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    11th April 2016
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    https://www.youtube.com/watch?v=Iybw9kbYUoA This is the same kind of sound my car is making, how about yours?

  9. #9
    VXRed
    Join Date
    13th October 2014
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    Default

    Quote Originally Posted by Norhidem View Post
    Could you guys help me out on other things i should ask the serviceman to inspect, since i still got ''used car warranty'' from the dealer.
    Depends how old the car is and how many miles its done. Beyond an engine oil and filter + pollen filter change, checks on the engine coolant stength and level, tyres, brake pads, brake discs, brake fluid level, brake pedal and parking brake efficency, lights, screen wipers, screenwash, air con and any ecu software updates required.

    Clutches, dual mass flywheels, gearboxes, drive shafts and timing chains, steering racks and front seat back release mechanisms have all suffered failures on earlier cars, so make sure you get any unusual noises or problems with these items checked out.

    ATE who manufacture brake systems incluing the GTC VXR abs/esp recommend that brake fluid is tested once a year and replaced when a car is three years old, and once every two years after that, see

    https://www.google.co.uk/url?sa=t&so...1N1QKgwmiYiPXg.

    Air and fuel filters may also need changing if its done a higher mileage.

  10. #10
    VXRacing ahead
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    26th April 2014
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    518

    Default

    Quote Originally Posted by Norhidem View Post
    https://www.youtube.com/watch?v=Iybw9kbYUoA This is the same kind of sound my car is making, how about yours?
    Mine does't sound like that , and anyway that doesn't sound right.

    I can hear the turbo spin ,that about it.

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