Style

iTrader: (1)

So think I've got the first can set up correctly for the head breathers, but correct me if I'm wrong. Now the second one I'm not sure where I want to take the feed from? I know it's somewhere under the TB, but where exactly, and where do you feed it back in? Just before the Turbo as pictured?

Assume you then need to blank something off?

I've had a look and read lots of threads but still a bit stuck, as below,

MattyB1983

iTrader: (51)

The crankcase breather comes up off the block just down the right hand side of the turbo. You'll see it comes up and into a "T", one pipe then goes off into the PCV valve on the back side of the inlet manifold while the other side goes off into the intake.
The best thing is to remove the original "T" and run a pipe directly from the crankcase to your can. You'll then need to block the pipe that goes to the PCV and the one that goes into the intake.

Also, on the can you've already installed I can see you've run both your cam case breathers into a "T" and then into the can but where is the other pipe from the can going ?? Ideally that wants a filter on it so it can breath back into the atmosphere.

Style

iTrader: (1)

the one is going from head breathers back into the intake, as read somewhere it can be best to keep the internal pressure thesame or something?

So I can just vent both to atmosphere, could I t them both into the same vta pipe?

Filski

woudl this help at all bud

https://www.scoobynet.com/technical-...n-install.html

FMJ

iTrader: (2)

My controversial thoughts on venting to atmosphere. Don't get me wrong catch cans are good. But they need to be baffled (not a cheap empty can) and they need to be run in the system properly not just vent to can to atmosphere. Most will likely disagree as they have a shiny catch can they like

On the classic you have the breather system as follows:

There is a pipe which is connected to the intake hose near the power steering pump. The pipe splits into two and goes to each head.

You then have the crank breather located just to the right of the turbo and to the left of the throttle on the block. This is divided into two. There is a small opening which leads back to the intake hose just before the turbo. There is a bigger opening which is connected to the throttle body via a one way valve (PCV Valve).

On boost and full throttle the PCV is closed. The pressure in the crank case exits the engine via the hose into the intake hose pre-turbo. It may also vent a bit through the heads but not much.

When you are off boost and there is vacuum in the intake manifold the PCV opens and the vacuum pulls dirty air from the crank case vent into the intake manifold to burn it off in combustion. This causes a vacuum in the crank case and clean air is sucked into it via the two head vents. As the head vent pipes and the two ways the crank vent can vent are all connected to system post MAF is is all read equally (no air escapes after the MAF has accounted for it).

If you VTA then you lose the metered air.

If you VTA and don't seal the PCV you will suck unmetered air in.

If you VTA you lose the vacum of the PCV which means new clean air is not introduced into the engine and the old acidic air will increase wear.

I have just been heavily researching this area myself and there is massive confusion about this system on the net. A lot of people think the rocker breathers are literally to let out pressure into the intake. Their real function is to let fresh air be drawn into the heads and down into the crank case. In the tech manual it confirms this.

Apparently the oil in your crank case gets quite acidic as it is used and these acids are bad for the engine (a reason you change your oil every six months even if you only did 500 miles). So ideally you want them properly flushed out via the positive ventilation system that Subaru designed. By just letting them breath then the dirty air to some degree will stay in there. Another reason the positive system is good is apparently it assists ring seal... not sure on that one but a few people seem to think this.

Now many have simply vented it all to atmosphere and probably noted no problems. But personally, now I understand how it works and the reasons behind it I am going to stick to a modified version of the original design that still works in the same way. I am going to run the crank breather through a catch can but keep it within the same routing of pipework.

I know its all a mess but it seems unlikely that Subaru would go to so much trouble making such a complex system just for the hell of it. For those who say "it's just for emissions we don't need it". I think this is part of the reason but if it were just for emissions the system could just be passive and they wouldn't have bothered with the PCV valve, the carefully designed t piece which gives priority to the PCV route rather then to the turbo intake and other bits.

I have striped my car of everything not needed (fuel evap system, aircon, head light washers and much more) but the PCV system stays.

Style

iTrader: (1)

Nice, that looks a good read. Ok so following that principle, could I simply take it straight out of the crankcase, through the can and then back into the PC, or the little things junction that divides it between the TV and back I to the intake?