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Buick Forum: Catch Can Install?
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  1. #1
    Join Date
    Aug 2014
    Philly PA
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    Catch Can Install?

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    Hi Everyone!
    Happy New Year and I hope that your Holiday's were wonderful!

    Quick question... Oil catch can on the 2012 GS - LHU engine.
    Should I or shouldn't I?

    What are the MAJOR Pros and Cons for such an install?

    I have been seeing a lot of buzz about this. If it is a must do, what brand can should I get?

    Speed is a matter of cost. How fast do you want to go?

    2012 Regal GS - 6sp Manual - K&N air filter, no badges, Slotted & Dimpled rotors.
    Planned upgrades: Intake, down pipe, exhaust?, (revised shift knob when I find it), window tint and much later reprogrammed ECM.

    Avatar is of my late 1998 GTP.
    When I ran my GTP @ the track on the 4th past 14.961 @ 91.88 MPH, my best time! Stock (never ran it after mods)

  2. #2
    GSTurbo's Avatar
    GSTurbo is offline Full Member My Buick(s): 2013 Regal GS, Crystal Red Tint Coat, Aisin AF40
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    Dec 2015
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    Re: Catch Can Install?

    What you need is a Powell air/oil separator. Do a google search, and it should bring up posts on the Cobalt forums about it.

    A generic catch can will not prevent valve coking on a DI engine.

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  3. #3
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    Jan 2016
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    Re: Catch Can Install?

    The idea of the catch can is to "catch" any oil blow-by that may occur, and instead of the stock setup routing it back into your intake, it gathers in the can so that you're not feeding that back into your intake. The theory is that our direct injection engines are more susceptible to carbon/gunk build-up on the intake valves because whereas regular fuel injection has the injectors squirting gas right on your intake valves (and effectively washing them), DI engines just have air and the occasional splat of blow-by go over them, with the oily blow-by baking itself to your valves. So the "theory" behind installing a catch can on a DI engine is that it will prevent this gunk build up on the valves, and with turbo DI engines the blow-by can be worse (especially at full boost).

    There's a lot of opinion and hearsay about catch cans and their effectiveness, because it's pretty difficult to gather any objective data without doing regular engine tear-downs. If you do a search for "Regal GS catch can" you'll find a few people who use them, but any that I've read about say they catch a pretty negligible amount of oil in them, like a teaspoon between oil changes type of thing. My personal opinion is that I'd only install one if it ends up being necessitated by other modifications. The stock setup seems to run fine and have good longevity without a catch can, especially during normal driving. Once you start tuning and upping the boost levels, and/or tracking the car and potentially running at max boost for long stretches, then you might start producing enough blow-by to worry about. On a relatively stock GS I think it's a waste of time.

    There are other options to making sure your intake valves get cleaned as well, like the 5th injector setup from ZZP, which adds a 5th injector upstream of the valves that will drip fuel on all of your intake valves. And as @GSTurbo said the Cobalt guys seem to prefer the Powell air/oil separators as being able to do a better job of catching blow-by and preventing the valves getting gunked. Again this to me would all be driven by some other modifications causing excessive blow-by, but if you want to do it to add an extra layer of protection / cleanliness then it doesn't really "hurt" anything. I guess to summarize:

    - catches at least some of the oil blow-by instead of having it routed into your intake and gunking valves
    - can be more useful in modified setups that run at higher boost or if you spend a lot of time at WOT

    - not as effective as other methods (air/oil seperator, 5th injector, etc)
    - likely won't catch much of anything on a daily driven car (unless you drive like a madman)
    - can get you in trouble with the "smog cops" if you're venting to atmosphere / tampering with factory emissions equipment
    - now you have to remember to keep an eye on it and empty it every once in a while

  4. #4
    stoopid is offline Full Member My Buick(s): 2015 Regal 2.0T FWD
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    Mar 2015
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    Re: Catch Can Install?

    Well said Andy.

  5. #5
    Join Date
    Sep 2013
    Chicopee, MA
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    Re: Catch Can Install?

    I've had the ADD-W1 sitting in my basement for about a year now, still not installed (pics attached)... technically it is an air/oil separator because it has a baffle on the inside for mechanical filtration, not just an empty can with no internals.

    It's been touched on by Walt G. before, but the PCV line from the Valve Cover to the Turbo is considered a non-serviceable part by GM and is a BITCH to remove (specifically the clips in fitting at the Valve Cover). This is to eliminate tampering with the PCV system, although the push-fit/o-ring fitting held by a single bolt at the Turbo doesn't have the same complications and can apparently be removed with a plastic line tool.

    Attached are a slew of pictures that I've collected on the internals of the "clip" system and tools to help me tackle this some day... People on other forums have somehow used the small cut end of a zip-tie in conjunction with a small, bent flat-head screwdriver to "release" the fitting on the 4 sides (in pictures as well). I tried for about 30 minutes and had no luck but am determined to do it... Others on this forum have simply cut the line before the curve on Valve Cover fitting because of the difficulty to remove it and went that route.

    I planned to mount it to the firewall with a catch-can bracket right behind my C.A.I.... run a short line from the Valve Cover to the ADD-W1, then an another line from the catch can to the turbo. If anyone has any additional insight or success with this please feel free to share! I've done about all the research I can do on it.
    Attached Images Attached Images
    Last edited by bbronner413; January 11th, 2017 at 05:30 PM. Reason: Added additional pictures

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  6. #6
    Walt G is offline Full Member My Buick(s): '12 Regal GS
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    Mar 2013
    25 miles SW of Chicago
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    Re: Catch Can Install?

    And remember that the only 'external' PCV lines on this engine are the ones that flow only when the engine is under boost conditions (another reason why this makes less sense if you're not tracking the car or 'driving like a mad-man'). The path the PCV takes when the engine is under vacuum conditions (vast majority of the time on the street) is through internal passages in the head and intake manifold. It is practically impossible to put a catch can in that path.

    I'm one of those with a catch can in the 'boost path', and I can confirm what was said above. I get as much out of that can after one track event (about an hour of track time) as I do in 3000 miles of non-track driving... about 1/4 cup.

    In fact, this is a timely question, because I just changed my oil yesterday, and didn't empty the catch can yet. It has been about 3000 miles since my last track event, which was the last time I emptied the can. Results: about 1/4 cup (I spilled a little dumping the can into the measuring cup):
    oil_catch (1).jpg

    Here is my install:


    Note: This is one of those super-duper cheap-o catch cans from E-bay. It sprayed oil all over the place until I sealed it up. I removed the 'oil level tube' from the side because I couldn't get it to not leak, and I had to seal up the inlet and outlet fittings with RTV, but now it doesn't spray oil all over the place.

    And I went the 'road draft tube' route with mine (rubber outlet hose leads down to the front engine mount). I park my car in the same spot in my garage every day and do not have any oil drips from that tube, so cheap-o or not, it is catching oil, and doesn't seem to be letting any out the outlet hose.

    I mounted mine to a little removable plastic panel on the front of the battery box, which is nice, because that panel lifts right out (with the catch can now) after removing the battery cover. There is a drain on the bottom of the can, but it's easier to remove the can from the car when emptying than trying to catch what comes out of it mounted in that location.

    Since mine leads to 'dirty air', I put a check valve in the outlet hose to make sure my engine never sucks in unfiltered air when under vacuum conditions. The 'inlet' for PCV under vacuum conditions is from the rubber intake tube that connects to the turbo inlet, to the valve cover, through a check valve... didn't want my catch can to become an unfiltered inlet.

    And nice pics Bbronner.. the blue collar style unlock tool is what I used to get the line off the connection at the turbo, after unbolting that little plate so I can get the hose up where I can work on it. It wasn't too bad. The connection at the engine seemed impossible to me, but ultimately, unnecessary too.

    And don't forget to place the blame where it belongs: the EPA. GM wouldn't make this 'tamper resistant' if not forced to do so by law.
    Last edited by Walt G; January 11th, 2017 at 06:08 PM.
    '12 GS, Quicksilver, 6MT, Nav, Sunroof, 19's, Trifecta tune, backup camera mod., LED DRLs in bumper vents, Wavetrac LSD, Sachs Performance Clutch upgrade, Werks shorty downpipe.

  7. #7
    Walt G is offline Full Member My Buick(s): '12 Regal GS
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    Mar 2013
    25 miles SW of Chicago
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    Re: Catch Can Install?

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    I did another track day with my car last week. I had about 2500 miles of normal driving plus this track event (about an hour of running full power pretty much constantly), and got 1/2 cup of oil out of the catch can.

    I think I was at the capacity of this can (again, it's just a super cheap catch can available from E-bay). I was starting to get oil out of my road draft tube, probably from sloshing/splashing in there. I got a couple of drips in my garage that night after I drove back home, and I noticed a bit of oil residue on the underside of my car near the tube outlet.

    But that's another 1/2 cup of oil that didn't go back into my compressor, through the intercooler (or get stuck in the intercooler), and back over the intake valves and into my engine. I think a strong argument can be made that it's not needed if you don't track the car, but an equally strong argument can be made that you do need it if you do track the car.

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