Catch can talk. So confused. Design/fab etc

[Gamble97]

I was talking to someone today and I thought I had the ideas of how to hook up a catch can in my head all right but according to him I am wrong. I also want to build one for a friend but need some help on it.
The way i thought a catch can was supposed to be hooked up (sealed can, no filter) is inline/inbetween the valve cover breather and intake pipe.

I also always thought anytime you hooked a can up to the pcv it had to be a vented can with a filter.

Onto more questions. So can every catch can be sealed as long as it has a vacuum line hooked up and the other way around. Every can be vented with a filter and not have a vacuum line hooked up to it?

My catch can I had made didn't specify a inlet/outlet and the fabricator said it didn't matter which way it was hooked up. He said it had a baffle and no steel wool. I can't for the life of me picture how it would be like this and not matter which way it was hooked up. Thoughts?

I want to build one for my friends car but I want to do it the right way. Do you 'need' a check valve if you go inline of the pcv? Should it be sealed with a vacuum line or vented without a vacuum line?
Are the baffles in the sealed and vented cans the same?


I found this picture online and this is the system they used for inline their pcv

You must be logged in to view this image or video.

Now say you want to add another vacuum port to this, would it just go on the top next to the other 2? Or does it need to be baffled as well? If not wouldn't it just cancel each others out?
Then when you decide to add breathers, what is under the breather?
Am I just overthinking this?

 

[99gst_racer]

The way i thought a catch can was supposed to be hooked up (sealed can, no filter) is inline/inbetween the valve cover breather and intake pipe.

This is correct. Anytime you have a negative pressure source (vacuum) drawing on the can, you'll want to use a sealed can so that it will draw on the crankcase. The guys who use vented cans are simply offering a way for pressure to naturally escape, which doesn't function as well as when a vacuum assist is used.

I also always thought anytime you hooked a can up to the pcv it had to be a vented can with a filter.

Nope, sealed. Because the PCV valve on the intake manifold plenum is a vacuum source at closed throttle. If a vented can were used, it would pull atmospheric air through the vent/element as opposed to air from the crankcase.

So can every catch can be sealed as long as it has a vacuum line hooked up and the other way around. Every can be vented with a filter and not have a vacuum line hooked up to it?

Yup, pretty much.

My catch can I had made didn't specify a inlet/outlet and the fabricator said it didn't matter which way it was hooked up. He said it had a baffle and no steel wool. I can't for the life of me picture how it would be like this and not matter which way it was hooked up. Thoughts?

Sounds right. The baffle is just an object or series of objects used to separate vapors and aerosols from the air stream. Filters usually work best, but baffles can work well when done properly.

In many cases, a baffle is used just to separate the inlet and the outlet, so it wouldn't matter which direction the air is traveling. Whether the can is directional or not really depends on how it was designed internally.

I want to build one for my friends car but I want to do it the right way. Do you 'need' a check valve if you go inline of the pcv? Should it be sealed with a vacuum line or vented without a vacuum line?
Are the baffles in the sealed and vented cans the same?

If you'll be using the intake manifold to draw on the crankcase, then it will need to be a sealed can. And yes, use a check valve because our stock PCV valves are known to leak.

You'll need to research more on baffling/filtering. There's a thousand different ways to do it, and they don't all function equally.

 

[Gamble97]

I really like the one I pictured above, but I'm assuming that would work not going through the pcv side, and only on the breather/intake pipe side?
What type of filters work best for the inside?
So you think the catch can I had just had a baffle to prevent oil from splashing up and then it didn't matter which way it was hookedup ?

I've seen a lot of people use a piece of aluminum with lots of holes drilled in it. How does this do anything?
One can was divided down the middle with wool on one side and nothing on the other, but the divider had holes all over it, so wouldn't it still want to suck up vapor?