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Removal of PCV one way valve.

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  • Removal of PCV one way valve.

    Been using the search function but not really getting the results i'd like.

    Since I'm running higher boost than stock now and not really trusting the little one way valve (although fairly new) in the PCV system i'm thinking of removing it.
    I see some of you has removed the T-hose including the valve and connect the N80 directly to manifold instead with good results.
    This however seems to be in conjunction of using a swirl pot or catch tank and I'm still using the stock system.

    Any BTDT on this?

    In my head the vaccum should be enough from the MAF hose to evacuate the fumes, maybe it will even introduce more fumes/oil in the turbo->intercooler tract without it.
    The positive being that I could get rid of 1 moving part which could affect boost etc.

    So, remove one way valve + t-hose and blank off the hose connection on metal pipe.
    OK or will it cause regrets?

    Audi S2 -1994 | 480 Hp 650 Nm | FlexFuel | MaxxECU | 3" Stainless | Porsche GT3 Front Brakes

  • #2
    On my RS4 I machined a solid piece of aluminium to the same shape as the valve and replaced it. All the pipework remains stock and you can quickly replace the valve if you need to.
    There’s also a billet alloy one way valve available which is supposed to be more robust but I can’t remember where from.

    S2 Coupe 3B Project

    Ur quattro restoration

    S2 Avant

    Boost is the new rock and roll!


    • #3
      Thanks newsh.
      That solution sounds smart actually, I'll keep it in mind if go forward.

      Did you notice anything negative in doing so?
      Other than that particular valve, is the RS4 PCV similar to the S2 version?

      I think the billet one you're mentioning is the 034 version, I think PRJ or someone warned about that one.
      That it is worse than the original ..
      Audi S2 -1994 | 480 Hp 650 Nm | FlexFuel | MaxxECU | 3" Stainless | Porsche GT3 Front Brakes


      • #4
        Could just do a boost leak test to say 2 bar and see if it all works.

        Stock setup is pretty much overwhelmed at stock power and grip, let alone upgraded. Better off doing the job once and properly IMO.
        Cheers'en, AndyC

        K24 Racing - K24R Products



        • #5
          I'm running all original PCV system + 034-catch can at 2,1bar, no problems. Pressure tested up to 2,5bar. Think it works just fine, but i carefully cleaned every thing when assembled the engine and also bought a new "non-return" valve.


          • #6
            Hmm not getting any alerts that this topic has new posts..

            I do pressure tests if I suspect boost leaks.
            My system was cleaned and new parts (incl non return valve) when I built the engine.

            I was just thinking that it would be nice to get rid of one failure source.
            Audi S2 -1994 | 480 Hp 650 Nm | FlexFuel | MaxxECU | 3" Stainless | Porsche GT3 Front Brakes