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pcv vacuum used for dv

Discussion in 'A3/S3 Forum (8L Chassis)' started by jezzy, Jul 23, 2012.

  1. jezzy
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    jezzy Member

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    Hi
    Can i use the old pcv vacuum (now blocked off) for the dv line?
    This line looks much better than the dv vacuum.
    Thks
    #1
  2. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Do you mean the big outlet on the underneath of the inlet mani in the middle? As seen here:

    [​IMG]

    You can use any one you want but it's tight to squeeze 4mm hose over it. You dont want to go any bigger then 4mm really or it will become loose on the DV end. might be able to get away with 5mm.

    I run my DV from the old EVAP vac source:

    [​IMG]

    That's using 4mm hose and I think it's a similar size nipple to the PCV one. I put the end of the hose into a cup of boiling water for 5 mins to soften it up to make it easier to get over the nipple.
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  3. jezzy
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    jezzy Member

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    thanks westy
    i will use the pcv line till i delete the evap and then swap over to the evap.
    on another note, when i did the pcv job, i bought the non return boat valve but didnt use it and the brakes are fine.
    is it necessary to use the valve?
    are there any pitfalls for not using?
    regards
    #3
  4. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    If you dont use it, the servo sees boost pressure and thats not a good thing...
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  5. Westy
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    Westy Double Dark Side! Diesel & 8P

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    I'm assuming you reused the 1 way valve that was already there? You must have used something or the brakes wouldn't be working :sadlike:
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  6. jezzy
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    jezzy Member

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    nope
    i bought the non return valve on ebay(the same one as your using)its this one 10mm Fuel Non Return Check Valve one way petrol diesel | eBay
    the valve is sat on the side doing nothing.
    And no i didnt use the valve of the pcv.
    the brakes work fine.
    But i will be fitting now after reading the above post
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  7. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Can you take a pic of the hose where the 1 way valve should go. I'm amazed your brakes are ok lol. I had that hose pop off before and it was pretty scary!
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  8. badger5
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    badger5 RIP S3dave Site Sponsor

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    servo seeing boost is not correctly (obviously) if thats what you have got it plumbed like now...
    Its feed is off the end of the inlet manifold however, not the middle like pictured
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  9. jezzy
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    jezzy Member

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    [​IMG] if the pic is not showing heres the link inlet picture by jezzy114 - Photobucket
    which way round does the one way valve go?
    im assuming that its drawing the vacuum away from the manifold, so the one way system should be away from the manifold so the vacuum does not return to the manifold?
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  10. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    arrow on the valve should point towards the manifold.
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  11. jezzy
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    jezzy Member

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    thank you
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  12. Westy
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    Westy Double Dark Side! Diesel & 8P

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    It's ok Bill we're talking about 2 separate things here. Jezzy is talking about running the DV from the middle vac source ;)
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  13. jezzy
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    jezzy Member

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    hmm just checked the valve no markings(cheeky feckers).
    So which way for the valve please?
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  14. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Blow into it, should be able to tell which way the air will flow.
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  15. jezzy
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    jezzy Member

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    thanks again
    Big thanks to all for your help
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  16. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    as above, you want to be able to blow towards the manifold.
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