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1G 1G DSM Valve cover Baffle - PCV affects with -10an breathers

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all black 4G63

Proven Member
Aug 5, 2019
Chicago, Illinois
Looking at the valve cover baffle area design of the valve cover after removing the factory baffle has me thinking, if I use the PCV valve with -10an fittings at the rear of the valve cover if vacuum is just going to pull from the -10 line right next to it and whatever is in my catch can? I will be using a 3 port Mishimoto tall can with filter (2 in and 1 out)

If you look at the photo I am not the only one that has used two -10an fittings on a DSM in that location in the past 30 years, but I am wondering if anyone has also used the PCV valve in conjunction? If so, will this have any negative affects by having that huge -10 line right next to PCV valve? I am using the Ravenfab aluminum baffle.

If you look at the factory design you can see that the Mitsu engineers added a little wall between the PCV valve side of the cover and the breather side and only one baffle port on the PCV side. Therefore, the only way positive crank case gases can get to the PCV valve is through the one open baffle port on the PCV side, "and whatever can get past the area between the spark plug boot ports." This is interesting and may be to reduce oil intake to the PCV valve? By having it this way the only way gases can escape during high boost is the breather side of the cover through the 3 baffle ports, which may be a reason why these motors have high crank case pressures during boost?

I am also wondering why Ravenfabs aluminum baffles use 2 baffle ports on the PCV side? maybe to assist in pressure relief during high boost? has anyone used the Ravensfab aluminum baffle successfully?

Thank you

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I like a dual sealed catch can setup. The most recent one i setup has a -6AN from the valve cover to CC, the outlet has a pcv valve (radium) to the intake manifold.
Then its got a -10AN from the valve cover into the other catch can and -10AN out to the intake tube.

if your gonna run a vented catch can, you should probably also add a front case vent if you don't have balance shafts or a vented oil cap. your gonna get alot more blow by with a vented can. With a sealed system the rings will seal better and you 'll get less blow by, less oil consumption, and your turbo will drain better.

I don't know if this applies to high HP engines cause all the 4 cylinders i have messed with have been 500hp or less.
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