Catch can questions

Posted by TSITurbo95, Sep 16, 2010
Turbo System Tech - 4G63 turbos, Intercooling, Boost Control, Wastegates, etc.

  1. TSITurbo95

    TSITurbo95 Proven Member

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    Ok, so I know what they are, and what they do, and searched and saw some diagrams such as this one, http://www.dsmtuners.com/forums/articles-parts-fabrication/263685-2-oil-catch-cans-setup.html. I fabbed up a couple catch cans, but want to use one. Currently I have one catch can from the breather to the catch can, then other hose back to the intake. Can I. . .

    Plug the intake hole for the breather line, and plug the breather into one catch can port, and plug the pvc with a check valve into the other fitting, and of course add 2 filters on the other two fittings? What would I do with the existing hole in the intake that the pvc pipe originally went to? What could I block it off with?
    Last edited: Sep 16, 2010
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  2. GRAVEDIGGER

    GRAVEDIGGER Proven Member

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    The way to do it IMHO is the 2 catch can setup you have linked in your post. That is the way I have mine done and I believe it is the best way. I think you may be misunderstanding what needs to be accomplished with a properly functioning pcv system like this. You need to keep the hose hooked to the intake because that is what is responsible for pulling fresh air into the crankcase at idle/vacuum conditions. Without this hooked to the intake you can have alot of contaminant gases getting into your oil, especially upon warmup as there are alot of gases present until the motor gets up to temperature. That is why there are two vents on the v/c. One for pulling air out and one for letting fresh air in.

    When the intake manifold sees boost though, it checks off the pressure at the checkvalve and/or pcv valve so that the crankcase does not become pressurized while the other vent going to the intake/breather on the other side of the v/c will have some air coming out (the opposite direction as under vacuum conditions) from blowby under boost. By having two cans you can collect the crap coming out of both sides of the crankcase. ;) Make sense? You would be surprised at how much you collect on the intake manifold side. I'm glad I am now catching that stuff instead of introducing it back into the engine, crankcase, oil, etc.:D

    Sorry for the long post if you already knew all of this. I just wanted to give you the reasons why I believe two cans are better than one.:)
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  3. TSITurbo95

    TSITurbo95 Proven Member

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    you just explained it ven better, and answered my quesion. I sill go withtl the twocatch can setup. Time to fab up another catch can. Thanks buddy.
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  4. GRAVEDIGGER

    GRAVEDIGGER Proven Member

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    I'm glad I could help you out.:) You can't go wrong that way.:thumb:
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  5. TSITurbo95

    TSITurbo95 Proven Member

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    So very true :). I spose after i fab a couple up this weeken ill post pics of my results
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  6. Calan

    Calan DSM Wiseman

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  7. TSITurbo95

    TSITurbo95 Proven Member

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    Thanks!
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  8. TSITurbo95

    TSITurbo95 Proven Member

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    Ok so last question, do I want to leave the pvc valve in or take it out? If I leave it in, I would not need a check valve due to the pvc valve, since that is what it is correct?
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  9. Black95TSIawd

    Black95TSIawd Proven Member

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    The stock pcv valve sucks. You can leave it in, but I have a dual catch can setup with the check valve between the intake manifold and catchcan and I used the reverse fitting for the brake booster where the PCV valve bolts in. It fits perfect and is even less of a restriction.

    Actually, my PCV side catch can had more fluid in it than the vents on the intake side last I emptied them.
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