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What Is an Oil Catch Can, and Why Doesn't Every Car Have One?

Discussion in 'Mace Engineering' started by MACE, Apr 12, 2018.

  1. MACE

    MACE Well-Known Member

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    For any car enthusiast, this article is for you. It's known that the harder a car is driven, the more blow-by gases there are. These gases mixed with oil particles from the crankcase end up in your intake via the PCV system and contaminate the manifold, and cause carbon build up on valves and pistons.

    To help solve this it is a good idea to install a catch can to filter the crankcase vapours so your intake system stays clean and no carbon builds up in the engine (even more important on SIDI V6 engines as there is no petrol injected onto the valve to wash it). Check out the article to find out more, and check out the website for a catch can to suit your vehicle.

    http://www.popularmechanics.com/cars/a22073/oil-catch-can/


     

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  2. Deuce

    Deuce Super Stock

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    That was a good and simple explanation.
    So if i disconnect my pcv, run it to a catch can instead, then run. A line back to the pcv port on the intake.
    Job done, more POWA!!!
     
  3. Smitty

    Smitty Well-Known Member

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    .... a wank for street driven vehicles
    and illegal of course according to the EPA

    an oil catch can is no replacement for a proper PCV
    valve and costs your engine nothing in terms of power
    (as a PCV valve only works at idle)
     
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  4. Deuce

    Deuce Super Stock

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    So while fitting a new intake to my 355 in a vehicle that goes to the drags once a year, and a powercruise once a year, in a country where it isn't illegal, i should still just plumb it up like factory??
     
  5. Dayvo

    Dayvo Because i can

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    I have one on ve sidi and its amazing how much crap it collects .
     
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  6. monstar

    monstar Naturally as-pirated

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    In the video John explains that it helps stop gunk and debris from building up on your valves and pistons.
    Is more important with direct injection I think, especially direct injection turbo with detergent oils.
     
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  7. Pollushon

    Pollushon Boost gives me a bar....

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    Catch can on an LS is a wise investment. Especially with a few kms and if you like to give it a squirt, these things slurp down oodles of oil. It's pretty easy to keep the system sealed and make use of the existing PCV so it's legal.

    20180406_173915(0).jpg
     
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  8. monstar

    monstar Naturally as-pirated

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    But why, to keep intake tract oil free?
     
  9. Pollushon

    Pollushon Boost gives me a bar....

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    And the rest of the internals. Oil will hurt performance and clag the engine up long term.
     
  10. immortality

    immortality Home of the smoky breakfast Bacon! Staff Member

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    Incorporate the catch can into the PCV system for best results.

    A catch can doesn't make power, but it does prevent the buildup of gunk inside the engine, in particular the intake system which may hurt performance in the long run.

    I don't have enough fingers and toes to count the number of threads on this forum about V6 engines with an irregular idle and TB issues 99% which are caused by the buildup of **** that comes through the standard PCV system.
     
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  11. mpower

    mpower Well-Known Member

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    really? both of my LS1's barely use any oil between changes. Catch cans feel like snake oil.
     
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  12. monstar

    monstar Naturally as-pirated

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    There is a lot of bull surrounding them for sure, and most stuff is a can with steel wool and mounting clips. As above the issue is Direct Injection mainly, and some cars have ineffective PCV. Both ideal candidates for better air oil separation for proper operation.
    But the idea that oil lowers octane is bull, straight up. It is all over the internet but strictly speaking in certain circumstances like cold start detergent fuel can cause uncontrolled combustion. That’s detonation and rare not WOT need more killawasps coz pinging.
    So apart from DI coking of valve stems, ineffective PCV causing gumming of TB / plenum, is not a performance enhancer, not for LS, is snake oil.
     
  13. MACE

    MACE Well-Known Member

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    In regards to the effectiveness of a catch can/oil air separator, I guess also comes down to the condition of the engine as well in regards to the amount of blowby it produces.

    This aside, oil consumption, does influence carbon build of the runners and chambers, which may be problematic in the medium to long-term (short term if the engine gets a genuine hiding and is not in the best of health), for engine performance. Along with a negatively impacting motor octane number (2 stroke oil, less of an issue).

    In regards to the impact of carbon, deposits, came across a nice research paper that covers it well, as shown in the link below.

    http://archiwum.inig.pl/INST/nafta-gaz/nafta-gaz/Nafta-Gaz-2014-04-04.pdf
     
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  14. monstar

    monstar Naturally as-pirated

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    I think the octane number is the measure of knock resistance of the fuel, independent of the engine it is used in. No doubt deposits cause combustion problems, but the introduction of oil does not lower the octane rating of the fuel whatsoever. The linked article proposes that deposits in the chamber leads to increased compression (!!) :confused: which in turn leads to an increased octane requirement (of the fuel) to be used.
    My point is that burning oil doesn't lower the octane of the fuel being used, as is commonly repeated over the internet. Yes indeed the highest specific output engines, 2T and those powering F1 cars are designed to burn oil as fuel.
    Latest research suggest low speed pre-ignition issue plaguing downsized DI & DI turbo cars, first thought related to carbonised coking (of the intake valve and chamber) deposits accumulated via PCV, is related to combustion of detergent oils though blow-by under certain temperatures and load conditions. Specifically the oil turns to an emulsion which when mixed with fuel under (DI) pressure ignites prematurely. This relatively rare and uncontrolled emulsion is neither oil or petrol rather a third hydrocarbon product from detergents in the oil.
     
  15. MACE

    MACE Well-Known Member

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    I will see if I can find an old article by a researcher from BP, where they have mentioned the degradation of motor octane rating due to oil consumption. The impact that this has on a healthy stock engine though, is minimal and taken into account in the factory calibration. On a tired engine, from personal experience, it does. Admittedly, that issue was solved by using an atmospheric catch can at the time, which is something that I would strongly recommend against nowadays.
     
    Last edited: Apr 13, 2018
  16. immortality

    immortality Home of the smoky breakfast Bacon! Staff Member

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    The burning of so called "oil" in F1 engines is nothing like the oil the cars we mere mortals drive :(
     
  17. monstar

    monstar Naturally as-pirated

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    Depends on oil quality of course, on this forum I think quite a considerable percentage of members with V8s use 100% PAO per our Penrite oils, same synthetic stuff as formula one. Of course they are not SIDI, hence my point that not everyone need rush out get a catch can coz makes poor performance.
    Introducing a little oil into the combustion process does help to quell detonation hence turn up the boost and or timing just a little bit. The oil acts as a sort of coolant to the charge, as certain high grade synthetic oils are a great deflector of heat. Use of explains why MB and Ferrari (now) have so much extra power in qualifying, and got busted last year.
     
  18. immortality

    immortality Home of the smoky breakfast Bacon! Staff Member

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    The FIA have limited how much oil an engine can consume during a race by a substantial amount so I'd say that avenue to gain advantage has been mostly negated.

    The other consideration on a lot of modern engines is the EGR system. Oil vapour and hot gasses in the intake = baked on crap everywhere. Twice as bad on any direct injection engine.
     
  19. Pollushon

    Pollushon Boost gives me a bar....

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    That's awesome dude, I like to hear success stories but it's just not true of every LS and every driver. The snake oil is in whether you need one and in your case, no, don't waste your cash.

    Like Mace pointed out it all comes down to blowby and blowby comes down to a multitude of factors. The fact a manufacturer puts a PCV system on means it's a real thing.

    To make the point simple I live in Canberra where we have racetracks called public roads and no shortage of challengers. My 250k LS gets its legs stretched everyday in every way :)

    The cost of this style of driving is a film of oil through my manifold. About 400mls per 5k oil change. That 400mls gets caught inside a glorified tin can now and only gases get through. It's worth every cent to me

    All the more important for when this gets tuned next week

    20180406_173852~01.jpg
     
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  20. immortality

    immortality Home of the smoky breakfast Bacon! Staff Member

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    Do I see water/meth injection?
     

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