[QUOTE=nick73;820297]^^I've noticed a tiny bit of oil residue on the plastic fitting that tees into the turbo inlet from the head/block breather piping. I'm guessing that's where I am losing a bit of oil at the track, pcv pipe work is bone dry. No oil consumption from street driving that I can tell.

Could you see any reason that the drain back to sump system wouldn't work if the pcv and it's vacuum return line were also utilized in the catch can arrangement? Would like to run it that way for the obvious legal reasons if possible.

Cheers.[/QUOTE]

Vacuum from manifold would suck some oil out of sump

using the Perth-WRX mobile app

[QUOTE=s20525xxx;820304]Vacuum from manifold would suck some oil out of sump[/QUOTE]


Are you sure?

[QUOTE=matto20v;820305]Are you sure?[/QUOTE]

0.7 bar is lot of sucking power. Whats ur expert opinion?

[QUOTE=s20525xxx;820306]0.7 bar is lot of sucking power. Whats ur expert opinion?[/QUOTE]

I'm not an expert, so I go easy on giving advice like this as it might cause someone's setup to go BOOM.

Are you an expert?

[QUOTE=Jacob92;820294]I have a hyperflow 4 port catch can with internal oil/air separator

The red lines go to intake and pcv
Blue are the smaller/baffled head breathers
Grey is crank breather
And green the avcs heads and crack pressure equalizer lines

using the Perth-WRX mobile app[/QUOTE]

Interesting. what's the internal design of the can? R head breather and crank breather separated by chamber/one way valve? If one of them has higher pressure, it could prevent the other to breathe properly, hence the oem design has them separated?

[QUOTE=matto20v;820307]I'm not an expert, so I go easy on giving advice like this as it might cause someone's setup to go BOOM.

Are you an expert?[/QUOTE]

No, but I am not internet warrior neither, and I genuinely want to help and learn.

[QUOTE=s20525xxx;820309]No, but I am not internet warrior neither, and I genuinely want to help and learn.[/QUOTE]

But you are an internet warrior! And your bad advice is going to cost someone dearly. You need to slow down on the (bad) advice you give.

Have you looked at OEM??? They join in the the same pipe back at the intake


The green line is a factory pressure equalizer as explained about in rosscos thread linked on page before



As for internal design there is a baffle plate that the oil ports are lower than and directs the oil to bottom of can then there is a filter and at the top the two air lines hook on to that would need to breathe like 1.5l of oil before it went back to motor my intake and cooler is completely oil free and has been since install 3 years ago

using the Perth-WRX mobile app

I could be completely wrong but the only way I reckon oil could get sucked backwards up from the sump is if the catch can was full and overflowing into the vacuum return line creating a siphon path while it was in vacuum.

A non return valve on the drain to sump would be piece of mind I guess.

Gordon - crude experiment but I just stuck a straw into a stubbie of beer (straw above the liquid level) and sealed the top of the bottle off with blue-tack. Was not able to suck any beer from the stubbie!!

Jacob, I know they r joined at the inlet pipe, but r the two nipples close to each other? In a confined space, ie catch can, air flow from the breathers can form vortex, where as in inlet, the flow from the filter is much more significant than breathers'. I said that because i had the grimspeed AOS, it joins head breather, crank breather and oil filer, as the result, it did nothing but push more oil to my tmic. The factory inlet, does have about -0.05bar pressure (vacuum), to help the ventilation. Crank and head pressure equaliser is not close to crank and head breathers, in my opinion, its not effective enough to completely compensate pressure diff. My crank breather collects more oil than my head breather.

Nick, your sump is not sealed as your bluetack test, it can let air in through inlet valve and crank breather. Why cars from cold weather need frequent oil change, the cold and moist air from surrounding environment in crankcase brings so much condensation into oil when oil start to warm up.