Not sure that what I learned about flow measuremnt applies here but it looks to me like the slots would accomplish two things:
1) create turbulence inside the tube to cause the oil droplets to come in contact with the tube wall and each other and coalesce.
2) bleed off some of the slower moving air along the pipe wall to reduce the velocity in the tube.

Edit: If the velocity inside the tube is low (say, inches/minute), then the slots won't do much but look pretty.

But I may be way off base.

nice DIY good job ... :tup:

Yeah, intended to break up the flow so that the oil hopefully adheres to the tubing and drips into the can, rather than being carried on due to the velocity of the air passing through...

When you complete the DIY, you can hear the air passing through the cans, it's obvious that the perforations are doing their job to break up the flow and cause turbulence.

I haven't emptied mine in a while, I should open them up and see what's in there. (Only driven ~400 miles if that, but most of it balls to the wall or dyno time haha.)

All of the above.

The idea was to break up flow entirely so that there's no clear path for oil to enter and then exit the can. Hence the perforations, unequal lengths, etc.

If these cans were made such that you could unscrew an entire end cap, I would have just filled the interior with large strand stainless steel wool type stuff, as it is, it has only small openings for the fittings and the drain, so it wasn't practical to try and fill the interior with any baffling material.

And yeah there are pre-made alternatives that aren't too outrageously expensive..

I'd give these a shot maybe if I had to do it again, though a pair of them will still run you $150.

Carbon Fiber Oil Catch can

This is the one I saw also at the Amazon link that I thought was a good alternative if someone wasn't looking to have to fab anything

Amazon.com: JEGS Performance Products 52205 Air Oil Separator: Automotive

The filter would need to be periodically cleaned or changed, but it should do the job well.

Sh0velman, do see a lot of blowby NA? I thought catchcans were more for boosted engines.

I think a pair of these would look good


Amazon.com: ADD W1 Red Baffled Universal Aluminum Oil Catch Tank Can Reservoir Tank Red Ver.1: Automotive

2 dumps, about 1-2k miles if that. 75mL.

This from my own AOS I made after the Crawford. Just a FYI a friend gave me his manifold to use for porting and it's just soaked in oil. He's NA also with no AOS or CC. I let it sit for a day and oil pooled on the ground under it. Very gross for both! Blow by freaking stinks!!


http://i39.photobucket.com/albums/e1...ps8fd40e3e.jpg

http://i39.photobucket.com/albums/e1...ps5dfd48ac.jpg

http://i39.photobucket.com/albums/e1...ps8d64fab6.jpg

http://i39.photobucket.com/albums/e1...psfc37715f.jpg

http://i39.photobucket.com/albums/e1...ps457d1b46.jpg

I just checked mine this morning. Between the two of them there was perhaps a tablespoon of cleanish oil. None of the coffee colored stuff Synolimit gets in his. This is probably because gasoline and water vapor doesn't condense in my cans but is instead evaporated back into the intake, only the engine oil stays in the can.

DIY: Dual Catch Cans with Air/Oil Separators... On the CHEAP!
 

This thread is great. I just finished mine but I did a single can. Thanks for the write up shovel. I also had cleanish oil in my can and filter
http://img.tapatalk.com/d/14/05/07/u6u9ajyv.jpg

What size NPT fittings do those cans come with? 3/8 Inch?

Just finished mine.

http://tapatalk.imageshack.com/v2/14...0b3c983d53.jpg

I bought a couple of GodSpeed cans to modify. Since I'm running the GTM Kit, it's impossible for me to install the cans near the headlights, so I'm going to install both cans on the driver side next to the coolant reservoir. Like your setup, 'm going to remove the PCV hoses from the intake manifold and PCV valve and connect them to the cans.

With the little space I have near the headlights, I might be able to install a compact air oil separator like the one from JEGS to the breather hoses. The hoses are currently connected to the turbo inlet pipe to the valve cover breather port. What do you guys think?

Here's my completed install. The 10 mm hoses I have are way too weak and keeps getting compressed from the vacuum.

[EDIT] I shortened and rearranged the hoses, so it's not so bad now.

Just want to give you guys a heads up about what sort of hoses to use when routing lines to your catch cans, manifold, and PCV. Stay away from silicone hoses. Use fuel line or PCV hose, which is rubber with some sort of nylon reinforcement. It won't deteriorate from the hot oily gases, and it can handle pressure better than a regular silicone hose. Below is an example of the kind of hose you should use:
http://www.amazon.com/Gates-27004-Fu.../dp/B0002JMFM0

My engine had some fairly bad idle surging, and after a few weeks noticed the hose was "sweating" oil from the PCV on both sides. I cleaned and further tightened the hose. After a few days one hose broke clean while driving causing some bad idling issues, throttle problems, and threw a code.

My idle surge isn't completely gone since it's possibly a tuning issue, but I'll continue to monitor my catch can setup to check for kinked hoses under vacuum, leaks, etc.