This is my setup, mishimoto compact can, a gtx pcv valve, and a gay little breather filter:

Attachment 238240

Attachment 238241

After a few days, the can has collected maybe a teaspoon or less of some stinky nastiness so it appears to be working.

your bov confuses that fuck out of me

Its one of those adjustable ones. Can either dump to atmo or recirc.

The bov has 2 outlets, 1 to back to the compressor and other vta. I can block off the one going to the compressor, get rid of the pipe, but I have to replace the inlet piping because of the gaping hole left over. I plan on doing this, just haven't done so yet.

Same setup here with very good results, the exhaust side vent is actually a good oil seprator if the PCV system is working.
The only thing missing was a better way to catch oil going to the PCV system (at least on a healty engine)
https://www.miataturbo.net/attachmen...ine=1424263309
This was my intake before installing the catch can on the PCV line http://i1084.photobucket.com/albums/...D0361DAA_1.jpg

I have a question regarding catch cans.

I posted some pics of the one I modified in my build thread, and 2 gentlemen recommended I remove the "fine" steel wool I installed and replace it with a much coarser material, and to use copper.

I get why to use copper, it won't rust. But why coarser? What's the benefit? Or what's the down side to using a finer material?

I ask because in my mind, I would think the finer material would "scrub" the vapor out of the air better. I asked about this in my build thread but no reply, figured this is the thread to ask anyways.

Fine mesh will scrub the vapor well but will retain the oil because of capilary force like a soaked rag, once it is soaked it will just pass the oil on as air bubles trough it.
A coarse material will carch vapors and fine drops and conbine them onto large drops that will drain to the bottom of the catch can.

Ok see my pics below.

https://www.miataturbo.net/attachmen...ine=1425308872

https://www.miataturbo.net/attachmen...ine=1425308872


https://www.miataturbo.net/attachmen...ine=1425308872


http://i231.photobucket.com/albums/e...psagsz7mcc.jpg


So with this setup, oil vapor goes in, then down through the fine mesh, then into open air, through the bottom, up the other side hitting the fine mesh on that side and up through it to the top, out the port.

So it at least seems to me that having it very fine on the inlet side is ok, as any oil that collects can only drip down, no way for it to get to the other side. On the "outlet" side, I could see possibly running coarser material though so it doesn't soak like you say. Still even if it did soak, what would happen? Seems like maybe it would just plug up sorta.

The other problem with the super fine stuff is pressure drop across the can.

Jonathan, that's something I do think may be a problem. There is a little resistance now, not too much, but the media is clean/dry. Soaked in oil, it will probably be 5-10x harder for anything to flow through it is my guess.

This is going on the PCV side. If it only flowed say 20% as much flow for the PCV vs if I had no catch can at all, would that matter? I honestly don't know! I don't think it would, at least as far as oil getting in the intake, maybe emissions would be a bit higher.

OK so my can setup is just a hose from either side of the valve cover into the can which has a breather on it. the can is collecting water and some vapors but my oil REEKS of fuel after only 1700 miles.

What can we do to make this go away? It's not good for the bearings I hear. Do we run a "draft tube" from the can to the pre-turbo intake so it can recycle those vapors and pull them out?

We sent a sample to Blackstone well see what they say

Never. It can promote detonation in a turbocharged car.

So why does the stock MSM and many turbo cars have a return from the can to the pre-turbo intake?

And how can I keep my oil less contaminated? I don't have the Blackstone results yet but my mechanic seemed pretty alarmed at the strength of the odor.

I'm going to block off the PCV hose, and for the breather, run it to a catch can and then to the pre-SC (in my case) pipe. I did this on my old turbo setup for 5 years, with no catch can, never had a problem, there was never much oil coming out to be a problem, but a good catch can will stop it.

Because for emissions compliance they can't "dump" the fumes into the air, it pollutes the environment. Personally I've done it both ways, and with it venting to atmosphere I smell it sometimes, and I don't like that, so mine gets piped into the engine.

I do NOT run PCV though, that dumps (not exaggerating one bit here, none) 10,000 times more oil into the intake than the vent tube. I ran my car for 5 years with the tube dumping pre-turbo, and after 2 years the intake track was still DRY, after 3-4 years it was slightly oily but no puddling/nothing excessive and it never got worse. I hooked up the PCV for 400 miles and it 100% SATURATED my intake manifold with oil. Screw that!

So what's a good catchcan setup that wont kill my oil or my motor?

1. Emissions.

2. Figure out what your mechanical problem is and solve it. Hint: It doesn't have anything to do with the catch can.

The car runs great but has a rich tune (blows black out of the back at high revs under boost). I don't know if this is a tuning problem or something mechanical. We have not done compression or leakdown but the tuner did not see or hear anything that led him to have concerns.

Ideas?

You have to pull vacuum on the can, so the fuel vapor is pulled out of the block. The only thing you (and pat) get in your can right now is from blowby forcing oil vapor out the breather. Any other time it is doing nothing.

You aren't in boost for long, so the total time your block is being cleaned is nil. A catch can is meant to catch oil and garbage, to keep that garbage from going to cause detonation. After you run a stupid rich pull you'll be coasting in vac, scrubbing 99.9% of the time.

The other side needs to be vented with a breather, so the vacuum isn't pulling against a plugged block, there must be airflow. If you don't like fuel/oil smell leaking out with blowby under boost, you install a catch can between the breather on the exhaust side in addition to the one you already installed on the intake side. It only functions in boost, when the PCV is closed by positive pressure.

The valve cover has a setup like this built in, but it is tiny and weak. I don't know how this is all so confusing to you all...

I don't understand what I have to do to make this work though. Put a breather where, the valve cover? Remove or keep PCV? Run a return from the can or no?

Just very confusing. The can had a lot of moisture in it so its doing something but the fuel in my oil is not good and will cut my engine life significantly.