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Revo PCV Upgrade

Discussion in 'A3/S3/Sportback (8P Chassis)' started by samsonQ, May 15, 2013.

  1. samsonQ
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    samsonQ New Member

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    [May 15, 2013]
    Evening all,

    I've read a lot about the Revo PCV upgrade kit and seen it for sale a lot for about £80.

    The brief description says it sorts out the problems on a mapped 2.0 TFSI engine?

    Could someone explain what it is (the PCV and the upgrade kit), what it does, how easy is it to fit and is it worth doing on my 2.0 Q?

    Mine's in for a stage one Revo in a week or so.

    Cheers

    Sam
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  3. S3Alex
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    S3Alex Rarely neutral

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    [May 15, 2013]
    Essentially the idea of all of these things is to reduce the amount of oil and water vapour ingested via the breather systems and into the intake.

    On a direct injection engine,all of this crud gets caked onto the inlet valve stems,and builds up to quite a significant degree,as there is nothing to wash it off,and the poorly designed stock PCV system is a major part of this problem.
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  4. MrLapou
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    MrLapou Well-Known Member

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    [May 15, 2013]
    Build your own for about £35.
    Dead easy, cut the pipe from PVC to crankcase inlet manifold, then install this type of non return valve, clamp each end with metal hose clamps.
    I cannot remember the OD required so please check ID of [pipe for a snug fit.
    Worked a treat on my TFSI engine.

    Pneumatic on-return valve,12mm Norgren T50P0012y

    Pic is of my homemade fix. Ignore the yellow tube and fitting. This was another mod I made (cost about £1.50) for a turbo boost pressure take off.

    Boost Gauge Adpater 003.jpg
    Last edited: May 15, 2013
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  5. wuta3
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    wuta3 Well-Known Member

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    [May 16, 2013]
    Can you explain the mod? Im not familiar with the direction of gas movement in the PCV. Does gas go from the head of the engine to the inlet manifold? Does the PCV then just re-introduce gas that doesn't to to the exhaust manifold back into the air/fuel mix? What is your valve doing to prevent coking of the valves.

    Also, why would Audi design an injection system that leaves the valve area unclean? Seems dodgy do me, mind you, I don't know of any valves slapping pistons due to the issue.

    Sorry for the questions, I know bugger all.
    Last edited: May 16, 2013
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  6. MrLapou
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    MrLapou Well-Known Member

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    [May 16, 2013]
    Crank gases flow from top of engine into the air intake manifold below. The non-return valve I installed stops the gases going the other way.
    This acts in the same way the valve in the large disc (PCV) in the pic. This disc has small flap and strings which fail, that's why the fix is needed.

    It's all down to reducing emissions.

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  7. wuta3
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    wuta3 Well-Known Member

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    [May 16, 2013]
    Thanks :)
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  8. H17YD L
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    H17YD L Active Member

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    [May 16, 2013]
    But with this mod you are still allowing all the oil & water vapour to go into the intake. If you were not loosing boost in the first place there's no point to it anyway. Better off blocking it off with a plug (I have this temporarily till I fit my catch can) fit a purpose made block off plate or a catch can.
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  9. MrLapou
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    MrLapou Well-Known Member

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    [May 16, 2013]
    Yip I know, but the style of VW/Audi PVC in my pic are known fail items. Like your doing, catch can is prob the final best option.
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  10. S3Alex
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    S3Alex Rarely neutral

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    [May 16, 2013]
    As Mr Lapou said,it's all down to cutting emissions,but the PCV valve system is poorly made and poorly put together.

    Even with a catch can,some coking will occur,as there is another breather that vents into the turbo intake and oil vapour from there will still end up on the intake valve stems.
    Pistons will not meet valves as a result of this,but the valve stems will get covered in junk.
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  11. H17YD L
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    H17YD L Active Member

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    [May 16, 2013]
    Yeh the pcv to the turbo is still there. Is there anything that can be done with this one Alex? Like blocking it off?
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  12. S3Alex
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    S3Alex Rarely neutral

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    [May 16, 2013]
    Thats the cam cover breather if I remember,and no,you cant just block it off.
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  13. MrLapou
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    MrLapou Well-Known Member

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    [May 16, 2013]
    I've to have not heard of anyone blocking of the rear breather to the turbo.
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  14. phil76
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    phil76 Active Member

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    [May 17, 2013]
    Hasnt the OE breather been uprated/modified many of times ,are these still not worth a knuckle shuffle then i take it ?
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  15. wuta3
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    wuta3 Well-Known Member

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    [May 17, 2013]
    Nice :)
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  16. AdamSansom
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    AdamSansom New Member

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    [May 17, 2013]
    Could you not pipe the rear crack case breather into the catch can along with the Pcv? Then the one return line will maintain the positive crank case pressure?

    Thats the one question I have about catch can kits to be honest, once the whole pcv assembly is removed and replaced with the blanking plate etc, what controls the crank case pressure?
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  17. S3Alex
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    S3Alex Rarely neutral

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    [May 17, 2013]
    I guess it would be possible,but there is a decent amount of oil that seems to go that route,from what I've seen,and as I've said,the catch can is not a catch-all,and the system would no doubt be subject to considerable fluctuations in pressure.
    The closed loop systems I had on my Cosworths took a crank breather,and cam breather,to an oil separator,which then fed back into the crankcase,but I am not sure if that sort of thing is transplantable to the TFSi.

    This whole PCV system was put together to control emissions,and not with any particular regard to the intake valve stems,especially on tuned engines.
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