What I am not sure of Rob is how much the feed back into the intake is used to create a vacum to suck the air through the whole system.
The crank is pressurised isn't it so I am pretty sure the oil vapour is under positive pressure, otherwise you'd end up with a situation where the turbo was essentially trying to suck the sump dry (slight exaggeration maybe) if it drew the vapour through.
Following this one with interest, purely because to me that looks really tiny, I'd have though it'd fill up rather fast.
my quandary is that catch cans are designed to capture the oil, not condense the vapour and placing these tins in a hot engine bay is not likely to be the most efficient way of doing this at all.
You could just vent the breather pipe via a small breather filter direct to the atmosphere, but this isn't practical for a number of reasons - chief among which is that you'll cover your engine bay in oil. If the vapour vents out the top of the bonnet it could easily cover your screen in oil, no fun, or if you feed a pipe down under the car you'll cover your car's underside in oil - worse still if it hits the exhaust you'll put on a smoke display the likes of the red arrows would be proud of.
I've seen catch can mods performed and they work to a degree but still seem to vent a fair amount to the atmosphere which would result in the above problem of oil staining.
I have in my mind an idea for this project, although it is a way down the list at the moment (waiting on my project halo atm, wink wink Jay haha) but my idea mounts a small oil cooler next to the headlights, in the small grill space so it has direct airflow, quite simply the vapour feeds in the top, should condense in the cooler and run out the bottom as nice cool oil, into a catch can somewhere down the bottom in the wheel arch or close by with an atmospheric vent from the catch can to relieve any back pressure. There is the option of feeding back into the intake from catch can instead of atmosphere, would depend how effective the cooler is I suppose.
Issues I could foresee with doing this, you would potentially be adding some length of plumbing to the breather circuit, which is not careful could add back-pressure. I don't think this will be a grave issue provided the cooler isn't too restrictive but have to be mindful of.
Ideally this would go down the drivers (UK) side but we all know the airbox kind of hogs that space, so mounting the catch can (would have to be lower than cooler) could be tricky. There is plenty of space around the front of the bumper, but needs to be accessible to drain and away from direct airflow to avoid stonechip / punctures, so may need to run across to other side to find free space - adding to issue above.
Only other concern I have is how free flowing the oil cooler would be to run under the positive pressure of the crank case, it may be that you will have to link back into intake to provide some negative pressure on the cold side of the system and if the system isn't then effective enough to remove vapour from the air, you're back to sq 1.