Oil Catch Can or Air-Oil seperator?

Discussion in 'Subaru Impreza WRX Help & advice' started by rudolfssau, Aug 12, 2018.

  1. rudolfssau

    rudolfssau Spec C Type RA

    What are the differences between these two?
    I know the CatchCan catches the oil, but the seperator, sends it back to the motor.
    And what would be the advantages of each?
    Just thinking about getting one for my STI....
    I was looking at this one...
    The Air-Oil seperator seems to be more appeling, because of the fact that it returns the oil.
  2. Fatharrydog

    Fatharrydog MY98 WRX Type R V-Limited 176/1000

    Depends what you are using your car for. If you plan on tracking it and changing the oil VERY regularly then an oil separator and returning the oil/milky sludge to sump is a good idea so the car doesn't drop oil in the circuit. If for normal use and you won't be changing the oil more than once a year then I would be wary about returning to sump. I have an RCM oil separator but didn't connect up the return to sump and instead collect it in a plastic can.
  3. rudolfssau

    rudolfssau Spec C Type RA

    I mainly use the car in winter, for ice track racing, in summer, i drive it on the B roads, maybe sometimes on the track!
    And i change the oil every 3k kilometers!
  4. edsel

    edsel V-Limited Member

    They are often used to describe the same thing, a baffled catch can isn't actually catching oil it its catching vapour which would normally be blown back into inlet. Cars running high boost and driven hard can generate higher than normal crankcase pressure resulting in smokey running and oily residue in the intercooler. If an engine is left standing moisture can also build up in the crank cases having a similar effect. My "baffled catch can" collects a coffee sludge which I assume the term "air oil seperator" comes from. This of course might be complete bollocks.
    • Agree Agree x 1
  5. benji

    benji Type RA Member

    Interested in this as I'd like to try a baffle version but keep all the lines running stock just a collected pot to help reduce oil in the intake pipe as I feel scoobs breath heavy
    • Like Like x 1

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