• From: Detroit Metro
  • Registered: 2018-02-10
  • Posts: 12

Topic: turbo cars - Subaru's maybe? Question about air oil separator

So, for one of the white Focus Club cars, we have a small turbo on the zetec engine. On the previous engine, we had a bit of a blow by / oil in catch can issue. Thought new engine would alleviate the issue, but only to a small extent. We have tried several things to slow down velocity in PCV tubes, etc... but to no real avail. At Gingerman, we ran the boost as low as we could, 4 lbs, and it ran ok and kept the majority of oil in the pan thankfully but anyboos level above 5-6 produces too much oil into catch cans to be able to run 8-9 hours.

My question is for anyone running a turbo really, do you guys run a catch can or an actual air oil separator that drains back into oil pan? Look at what is available in terms of products - seems most things are made for Subaru but there are a few generic ones around.
Do any of the fellow turbo Lemons folks run into similar issues with oil in crank case vapor and having to return the oil back to pan? Do you run a slight vacuum onto the can maybe by hooking small tubing to turbo inlet or?

Dr Google is all over the place with information, just looking to see what some of the fellow Lemons turbo folks are dealing with before going too deep.

Any experience would be awesome
Thanks
Pat

  • Registered: 2013-11-15
  • Posts: 672

Re: turbo cars - Subaru's maybe? Question about air oil separator

I have a Volvo turbo.  I run a catch can and drain back to oil pan. I was running vacuum from the intake before the turbo, but I was sucking too much oil into the intake and now just vent to atmosphere.

Team whatever_racecar #745 Volvo wagon
  • From: Detroit Metro
  • Registered: 2018-02-10
  • Posts: 12

Re: turbo cars - Subaru's maybe? Question about air oil separator

For the Volvo, where / how is your return oil line - drain? What size line is it and where is it placed? I would think that above the oil level, the drain would compete with the crank case pressure unless the line was large enough to let gasses flow up if needed while allowing fluid (oil) to drip passed…?

  • Zacks
  • Ripened Lemon
  • Offline
  • Registered: 2022-10-17
  • Posts: 111

Re: turbo cars - Subaru's maybe? Question about air oil separator

While catch cans won't hurt anything I tried one once on a non racing wrx, never really caught much.   Maybe an air oil separator is better idk.

Our non turbo subaru burned oil as well
I've had good results running thicker oil (5w40) although that started burning on day 2.  Should have changed the oil overnight but it was raining...  Talked to a turbo subie team and they where running 10w50 dunno if that's too thick or whatever but they where fine.

Installed an oil cooler for next race hopefully that helps too.

  • Registered: 2013-11-15
  • Posts: 672

Re: turbo cars - Subaru's maybe? Question about air oil separator

Prodiclson wrote:

For the Volvo, where / how is your return oil line - drain? What size line is it and where is it placed? I would think that above the oil level, the drain would compete with the crank case pressure unless the line was large enough to let gasses flow up if needed while allowing fluid (oil) to drip passed…?

I kind of F'd that up.  On the block under the intake manifold is where the stock system used to sit.  It has two holes, one for gases to come out, and another with a tube that extends into the oil pan.  My tube is not long enough to get below the oil level, so I think they both work for gases to come out of the crank case.  I can't replace the tube without pulling the pan.

I think one is -10AN and the other is -8AN.  I have a custom adapter that attaches to the block.  I would think if you put a -8 or -10 AN plug into your oil pan you would be okay.

Team whatever_racecar #745 Volvo wagon
  • Registered: 2013-11-15
  • Posts: 672

Re: turbo cars - Subaru's maybe? Question about air oil separator

What do the rally guys use?

Team whatever_racecar #745 Volvo wagon
  • From: Detroit Metro
  • Registered: 2018-02-10
  • Posts: 12

Re: turbo cars - Subaru's maybe? Question about air oil separator

Good Q - I know a few guys out this way (Detroit Metro) that rally, I reached out to them too - hoping to get some good feedback as well. Fairly certain this is not a new issue, just hoping to see what others have done and are doing and learn

Thanks again All
Pat

  • From: Queens, NY
  • Registered: 2014-05-17
  • Posts: 602

Re: turbo cars - Subaru's maybe? Question about air oil separator

make a small cyclone separator that would drain back into oil pan, or valve cover?

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