i've been trying to search this topic... but no luck.

most of pic/write-ups i found,
a lot of you guys installed oil catch can like this...



but can i do this?



i'm also curious to know
what is the benefit of doing it like the picture #1, why people choose to do it like that,

and difference between #1 method and #2 method.

my car is na with cai, btw.
(a lot pics i found, was with sc.)

 

You can, but there is no benefit to doing this. The PCV opens when there is positive pressure in the crankcase due to blowby, (which is exacerbated by boost) and dumps back into the intake, to make sure those gases are burned for emissions reasons.

Modifying it is not any more emissions compliant than just blocking it off, but it could be potentially a bit less polluting. other than that, no difference. If you don't hook up the manifold connection, make sure you cap it off.

 

The PCV Opens when vacuum is applied from the intake manifold, It is not opened by crankcase pressure.

In the bad old days before emmisions controls, crankcase vapor was released to the atmostsphere through a open breather in the valve cover. CARB/EPA didn't like this to much, and mandated that crankcase vapor had to be burned. Crankcases have to be vented/evacuated.

Seung, option 1 is a remote breather. It's no different than sticking a filter element directly on the valve cover.

Option 2 is a Oil seperator, which is how mine is plumbed. Crankcase vapor is still being pulled into the intake manifold, If the seperator is doing it's job right, the oil contained in the crankcase vapor collects in the bottom.

 

Are you sure about that?

If that is the case, then the PCV will never open if you don't connect it to the intake manifold. I'm sure vacuum helps it open but it doesn't take much crankcase pressure to open up the breather.

 

I'm pretty positive. What pressure do you believe will open the valve, 20in hg of manifold vacuum, or slightly above atmospheric from the crankcase?

 

http://www.mycarwizard.com/autoshop/exhtext.html

 

thank you guys...

hmm... so which method do you guys recommend?
(actually this is the question that i wanted to ask the most.)

 

Heh, I regularly blew my dipstick out of the hole in my old turbo eclipse.

I'm not arguing that vacuum is not what normally opens the valve, but if you disconnect that line, the PCV must still open from crankcase pressure.

Anyway, it won't hurt anything either way. Personally, I would get a catch can with a breather and connect both the breather and the PCV to it, and cap off the manifold, to keep your intake and filter from filling up with oil.

 

Mine's hooked up like option 2

 

A turbo eclipse is going to see a bit more crankcase pressure than Seung's NA car.