Stock PCV, Catch Can or Air Oil Separator

Well, on my current adventure of installing my Turbo back exhaust I found some yellow sludge that resembled a dark Vaseline. I found a thread on Nasioc that explains whether or not a Catch Can, Air Oil Separator is really worth it for a Daily Driver. I my self will alow the stock PCV system to be un-modified; no CC or A/O Separator for this guy.

http://forums.nasioc.com/forums/showthread.php?t=1866781

You should do an Evac system. They are sweet and can make good power on bigger turbo setups. If you haven't seen them they use a one way valve welded into your exhaust. They draw a lot of vacuum and rreally help seal the engine up.

If you do a catch can keep the setup as close to stock as possible and make sure you hook back into the intake to use that vacuum. Running them open atmosphere works but then you loose the benefit of using the vacuum which helps seals the rings as well as gaskets. Lots of people with Evac kits or proper catch can setups say if they had small oil leaks on seals they go away.

Here's a link to a site I frequent that a lot of people have done Evac kits. On big turbo supra's they pick up as much as 60hp.

If you have questions or want some pictures let me know. Seems like people are always messing up how they install catch can setups and blowing out dip sticks or getting tons of oil in them. This is a system I understand really well and would be happy tp help. My advice is use the stock PCV system with a catch can, however if you don't plan on getting too wild with the engine I would stick with the stock setup for simplicity and it works fine.

Jason, your the man!

edit, I didnt see a link

Whoops this may help.
http://forums.freshalloy.com/showthread.php?t=175664&highlight=Evac+kit

Hey Dougie did that car have Mobile 1 in it by chance? Just curious.

I really like my Perrin catch can. I am such a poster boy!

Catch cans are super popular with the DSM crowd too.

haproot wrote:

Hey Dougie did that car have Mobile 1 in it by chance? Just curious.

I bet it did, but have no clue. :/

I still need to install my catch can (thanks again Mike!)......... Once it started getting cold I started getting lazy

RedMitsu wrote:

Catch cans are super popular with the DSM crowd too.

Unfortunately catch cans are popular in the DSM world because of the style of tuning for most DSM tuners. DSM tuners are known for having a very unique style of tuning, they run the engines very rich to allow for more boost/timing. Far from the best and most efficient way to tune. This causes more blow-by. However on any mildy built engine they are a good idea. On stock engines there really should be no need for one.

One thing is I know I get asked on a lot of other forums how to hook them up and people do it wrong a lot. So to put this system in a simple way what the goal is for a catch can is to allow your crank case to breathe while removing the oil from the air. If you vent the valve cover/crank case to the atmosphere it really doesn't matter as long as you don't have the oil blowing out onto something like the exhaust manifold. That can catch fire. The reason it is best to have it hooked to the intake or use an Evac kit is to use the vacuum created in those systems to help pull the piston downward and to help the rings seal easier. Also the easier it is for the system to breathe the easier on your engine to a point. Too much vacuum and you may begin to pull more oil out with the air, but without a vacuum pump you would probably never create too much vacuum. So to hook it up you need to know what is a vent and what is moving fresh air in and out. Many people hook the system up so there is no place for the air to get out or in. This causes dipsticks to blow out, or excess pressure for seals that will rob power as its working against the engine. This is one of the simplest systems on a car but is very commonly misunderstood. If anyone is installing one and needs suggestions or wants help to learn how the airflow will be moving let me know and I'll be more than happy to help. There is also a ton of info on this subject all over the web.

ts4l wrote:

This causes dipsticks to blow out,

This is also very common with the DSM crowd

If I run it from the valve cover to the intake what happens when vacuum becomes a posotive number? Now I would be putting that compressed air into the valve cover rather than venting it? so then if I had a catch can how do I release pressure once it gets there? do I just stick a filter on it? and how is that different from the stock vent that goes to the intake now? How are the babies?

The intake is never positive! The manifold is can be in a positive situation which is why it uses the pcv valve which is a one way valve. You want to leave that stock in my opinion then use the valve cover vent then connect that to the catch can. Then you can either vent it to the atmosphere or do it similar to stock and in many people's opinion the best choice and hook back into the intake! This is also the smog legal way but helps the engine seal the best! I'm typing on my phone so i'll explain better later on.

You can also run the PCV port to the catch can you will just need a catch can with more ports or modify the one you have.

I just got all the stuff to vent the case/VC using the vaccume created with a slotted pipe to the exhaust from APC. A short list: #10 AN fittings, One way check valve, slotted exhaust vaccume pipe. Still need the flex hoses but they have all that stuff there. I also landed a chunk of aluminum to scratch build a catch can so I dont have to spend 130 bucks on one.

That's sweet! Can you weld aluminum? Seems not many around here can. I paid a small fortune for all my aluminum to be welded up.

Make sure you weld the portion going into the exhaust at around a 45 degree angle to get the best scavenging effect. I had planned on doing a similar setup but aleady had it vented to the intake so I left it alone. Should be sweet. Post pictures when ya get it all done. And obviously as you probably already know out it after any 02 sensors and get rid of he cat if you have one.

I have an ac/dc tig machine that lets me weld alum. they arent the sexiest welds but they will do the job just fine. I am scratch building a catch can out of a piece of 2" alum pipe and some plate. No cats or mufflers for eric, just a 28" glass pack in the middle of a 2.5" straight pipe!!!!! I'll keep yall postd.