Dump Valve noise under acceleration

Discussion in 'Mechanical - Engine, Gearbox, Exhaust etc' started by John Alkiviades, Nov 6, 2019.

  1. Have now owned my R26 for few months.
    First thing I said to myself was to remove the dump valve as I drove home.
    I open the bonnet and there is no dump valve.
    So what the hell is that noise.
    After some investigation I replaced the Recirc Valve as maybe the diaphragm was split.
    Still noisy.
    Sounds like boost is leaking on acceleration and it chatters on full load when changing gear.
    These noises are normal if you have a dump valve fitted that's vents into the atmosphere.
    The performance is faultless and boost gauge is reading up to 1.5bar.
    Is this a common noise for R26 Megane?
    The car does have an induction kit so this might be the reason.
    Please help me if possible as my kids wont let me take them school as they are embarrassed of the whooshing noise.
     
  2. Probably the induction noise. Some pictures and a video would help.
     
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  3. It'll be the recirculating valve, more noticeable if you have a cone air filter fitted
     
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  4. The standard boost for an R26 is approx 0.8 Bar (11.5 psi) so it looks like yours is running some type of map - 1.5 Bar (21psi) is a little higher than I would expect from a Stage One but within acceptable limits.

    You would usually need to uprate the Recirc valve to handle that amount of boost It's almost certainly the valve that is causing the Whoosh - It could just be flutter from the valve sounding through the Intake system or it could be one of the connections somewhere that is leaking - the leak would mean that you are still getting a standard amount of boost but are losing the stage one upgrade's additional

    I would get a can of Carb/ intake Cleaner and spray it around the vacuum tube joints at idle - the revs raising indicate a leak

    As for the kids depending on their age just tell them the sound is fairies chasing unicorns or the Flux capacitor charging :laughing:
     
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  5. Thanks for all the feedback.
    I will try and take a picture today of under the bonnet and a video.
    The previous owner had an induction kit and scorpion exhaust fitted and said he needed a remap for it to run properly.
    He said the remap has increased the bhp to 246.
    I thought the boost was too high but after speaking to ktec racing they said that is pretty much standard after a remap.
    I have installed an uprated recirc valve as I thought it was faulty but noise still there.
    If I fit a hybrid turbo will it still have a recirc valve on the body of the turbo?
    Or the solution might be to remove the induction kit and refit the original airbox then at least the bleed air will return to the intake box.
     
  6. I have a similar sound on my 265, its just a combination of the uprated recirc valve and induction kit.
    Fitting a hybrid turbo wont change the recirc valve either, it might just make it louder. Have always had the uprated recirc valve and I never really heard it before the induction kit was fitted either.
     
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