IFeelYourPain

Does anyone have a diagram of how a catch can should be mounted on our tC's?

I'm running quite a bit of boost so under pressure the PCV valve wouldn't open,

I need to figure out how to pull vacuum so I can get the catch can to work properly.

bbsciontc

For the tC, run the catch can between the port on the driver's side valve cover and where it would connect on the oem intake pipe. It never goes under vacuum, but any crank case pressure the builds up under boost would vent out from this location, as the PCV valve will be closed as you stated. If you watch dyno videos of boosted tC's that have a "breather" filter here, you will see smoke/vapor coming out.

I haven't put a catch can on yet either, but I plan to do so this year. I did notice some oil reside when I took off the hose, so I'm sure that's the location.

IFeelYourPain

Could this be why in boost I have smoke coming out my exhaust? Compression is good, not loosing coolant, I notice a little oil lost over the last 2000 miles, but the only time it smokes is in full boost when I shift gears or let off the gas. It looks like white smoke, but sometimes looks like it has a blue tint to it. I didn't know our PCV valve was opposite of the SRT4, it uses vacuum to pull from the PCV.

Couple more things.
Should I just use a breather or should I run a Air Oil Separater?
Could it be too much oil pressure going to my GTK550 causing oil to seep past the rings? I'm not sure of stock oil pressure on my car, I was planning on buying an oil pressure gauge, but wanted to know which would be more likely, to buy a catch can or an oil pressure restrictor.

bbsciontc

Smoke out of the exhaust could be many things. It could be the turbo oil seals, blow-by etc. It could even just be the air fuel mixture. Some oil loss is normal. It makes sense that there will be higher crankcase pressure in a boosted car, so in turn you would expect greater oil loss through the PCV system.

The PCV system in our cars does work on vacuum as well. It is connected to the intake manifold, which is normally always under vacuum in stock form. However, when you run forced induction, you put the manifold under pressure (only in boost obviously). This pressure will be higher than the crankcase, and the PCV valve will close. Now the crankcase will have to vent out the path of least resistance, which will be the from the valve cover where it connects to the intake piping.

Basically, under vacuum, crankcase pressure is relieved through the PCV valve located at the back of the valve cover which is connected to the intake manifold (the port on the driver side of the valve cover serves as an air "intake" into the crankscase). Under boost, everything changes. PCV shuts like it should, and the driver's side valve cover port becomes the relief point for crankcase pressure.

This does bring up an interesting point though. Technically, a proper catch can setup would be two independent systems: one on the intake manifold side to catch oil vapor under vacuum conditions, and one on the intake piping side to catch oil vapor/combustion byproducts under boost. That would be the proper way to do it. However, crankcase pressure will be much more significant under boost due to blow-by, so the system I recommended would be fine for a boosted tC.

bbsciontc

Regarding your last points, I don't recommend going the breather route. I see lots of people do it, but in truth, this creates a small vacuum leak as air entering the breather at idle eventually gets into the intake manifold, without being "read" by the MAF sensor. This is why the oem setup is done like that. It pulls air after the MAF sensor.

The oil pressure thing you mentioned about your turbo could be a possibility. Unfortunately, I'm not familiar with your turbo, but most ball bearing turbos do recommend using oil restrictors. Only journal bearing turbos need strong oil pressure. Don't know if yours is a ball bearing type or not.

IFeelYourPain

There is no shaft play at all on the turbo. It's only got 10,000 miles on it. I thought about A/F Ratio, I don't have a wideband yet, this was tuned by a good tuner and there was no A/F issues, but I still am going to buy it, I just want to put my money in the most important thing at this moment (both are important, but one may solve my issue now), as smoke out the back is no good. I was going to purchase a catch can this check and wideband next check.

So you say I only need one catchcan? The way it was set up is the PCV is run normal, but the valve cover port is just a breather. Is this ok? Then I just run a catch can from the PCV valve? Is there a catch can you recommend?



There are custom GTK550's that are journal bearings, but I don't think mine is. Is there anyway to know for sure, and any way to see if I do have too much oil pressure going to it and how much is needed for ball bearing turbos?

bbsciontc

The breather does work in terms of allowing the crankcase to vent under boost. The issue with this is that a breather on the valve cover acts just like a vacuum leak. When the intake manifold is under vacuum, it pulls the pcv valve open. This in turn puts the crankcase under a light vacuum, and air gets sucked in through the valve cover port through the breather. The air that enters the intake manifold through the PCV is therefore unmeasured by the MAF sensor, and may cause you to run slightly lean under vacuum. Under boost, the PCV closes and this becomes a nonissue. You will however get oil buildup on the breather over time. That area might get messy.

Putting a catch can on the PCV is not a bad idea either. The difference is that this catch can will function while the car is under vacuum (idle and cruise), but would do nothing under boost. This isn't a bad idea for a daily driven car that only occasionally sees boost.

Regarding the journal vs BB turbo, I can't say for sure, but if there is only an oil line going to the turbo, it's probably a journal bearing as it is relying on oil for cooling. If you have a water line as well, it could be either I believe. I am no expert on the turbos that are out there. Your best bet is to contact Turbonetics support for recommended oil pressures. My oil pressure gauge reads upwards of 60 psi at high rpm, and even higher (80+ at 3.5k rpm) if the oil is cold. This is high for a BB turbo.

IFeelYourPain

No oil on the breather yet, it's pretty clean, but I will keep an eye on it.


So if I am seeing smoke after boost, then maybe it is the PCV valve as when I see smoke, it's only when I come out of boost? I'm trying to figure out where to put this catch can, and from what you are describing if I am not seeing any smoke under boost, but as soon as I let off the gas a puff of smoke comes out, maybe when it pulls vacuum it's sucking oil up and burning it. I'd rather not deal with carbon build up, so if this is where you think I should put it then I will put it there. As for setting it up to the one for the intake, where should I run this to keep from having a vacuum leak?
I will know for sure if I am running rich/lean in the next couple weeks, (I been taking it easy for fear of smoke) but I have noticed on startup, (like once every month) the car will run rough under 2000 rpms, so maybe this could be the result of the breather being on there?

I'll contact Turbonetics, I don't know why I didn't think of that.


TLDR;
1.) Could the oil burning be from the PCV since it only happens after I am out of boost, maybe the sudden boost to vacuum sucks it out, in which case the best spot for the catch can would be the PCV for now?

2.) Could the breather vacuum leak cause a rough start once a month or so? It really is random but you said idle and if I keep the RPMs above 2000 it runs fine, after a restart it's fine.

3.) How would I go about fixing the breather to remove a boost leak?

4.) What's a good catch can for around $100 for our cars?

Thanks for all your help man. Still new to the Scion crew, I love her, but sometimes she causes a headache (Kinda like my wife )

bbsciontc

LOL, trust me, I know about headaches. I sometimes wonder why I do this stuff, given how it affects reliability and drivability, somewhat. But then I remember how slow the car was N/A and don't care anymore, haha. I've had this car since new, almost 12 years ago. I figure I got my money's worth out of a car I bought brand new for under 17k.

For your questions:

1) I honestly don't know if the smoke would be from the PCV, but you are correct that when you snap the throttle closed after boosting, the manifold will go under a strong vacuum and open the valve. I just can't imagine that there would be a whole lot of vapor getting sucking into such a small opening in the valve. I would tend to think it's just some unburned fuel from when ignition is cut, but I'm just speculating. A catch can here is not a bad idea though.
2) I think this is possible. The breather doesn't become a huge leak as the opening in the PCV is not very big, but at idle the effect can be more significant since there is not a lot of airflow anyway. I'd definitely look into it. FYI, you're car may run funny at first, as it likely adapted to somewhat compensate for this leak. You can either give it time to "relearn" or reset the ECU.
3) The breather was originally just a tube that connected from the valve cover to the oem intake piping. The best way to fix this would be to take off the breather filter and reconnect it to the intake after the MAF, just like OEM. Ideally, it would go into a catch can first to keep the oil vapor from getting sucked in. Definitely do no cap/close this off though. It needs to be there for crankcase pressure relief at WOT, or else you'll start blowing oil seals.

4) I don't have one (I really need one) but I've hear good things about the Mishimoto catch can. It has a proper baffle setup, and will be much more effective at removing oil vapor than the ebay specials which is just a can with no internal baffle.

IFeelYourPain

1.) I figured it's one of the two things. It's just deciding which is more important over the next two weeks. Oil is bad because of carbon build up, but so is running rich. Buying the Wideband won't solve my problem, still have to put it on and pay someone to tune it (I can't find anyone who tunes split second piggy backs in my area)

2.) Crazy how cars "Learn" when is SkyNet again?

3.) If the catch can is on the PCV how would any other oil vapor get sucked in?

4.) Anything more in the $100 range that isn't eBay garbage?

xile6

I attached mines photo.

I ran a similar set up on my Civic but on the Civic it was just vent.

On the tC its routed back into the intake to have some vacuum.
I remove the PCV valve and put a 8AN fitting.
Remove the valve cover breather and put a filter on it.

So the system will pull fresh air in from the mini filter on the valve cover and the blow by and pressure will be suck out the PCV 8AN line.
That line goes to the catch can were all the oil is drop off and nothing but air comes out the other end.

I've check the hoses and the outlet is always dry and clean and normally there a small amount of oil in the can between oil changes.

This setup keeps the valve cover under vac even while boosting.

IFeelYourPain

Ok so I got my wideband installed and had a tuner look at the readings and all is good. I had my buddy behind me when I was under boost and he said the smoke was blue, so it's definitely oil and not unburned fuel. I had someone custom fabricate me a catch can with two individual setups (he was busy so it took forever) and now I need to know how I should set this up. You said in this post that I would want to run it from the breather to after the MAF but in a previous post you said I would want to do it before the MAF so it is able to monitor the air. Just trying to figure out which is the route I should take. The PCV Valve I will route to the other catch can and back to the vacuum box where it's currently connected. Are there any other spots I am missing? I noticed under the car on the driver side there is another breather, should this be routed to the catch can or where should it go? Is it vacuum as well for venting?

Here's my engine bay for reference if needed:


Thanks again for all the help.

xile6

Crazy setup you got there.
As far as the catch can setup it works like this.
The PCV sucks air into the Intake. The port on the valve cover is an inlet.
Yes that is correct it sucks air in fresh air through the port on the valve cover.
So just by putting that breather on it as you have pictures. Your letting in unmetered air. This would happen at idle and high vacuum.

The correct way to get everything up is to remove the PCV and run that to the catch can. Then run the line from the can to the pipe pre turbo.

This way it will always be pulling blowby and crank pressure.
If your can isn't good your end up with oil in the tube and possible some on the turbo blade.

The other way of doing it is to simply put the catch can between the PCV and Intake (this can must be 100% and leak free or your have a vacuum/boost leak)
Then the valve cover would need a line after the MAF sensor.

From the photo you have your blow through which means you can do that or your pump PSI into the crank case.

IFeelYourPain

Thanks man, she's pushing a lot of boost, so I want to make sure to do it right as possible.

I made a diagram to see if I got it right. I'm not sure what you meant by pre-turbo, because the CAI would be before the turbo, but I feel like it doesn't have much vacuum if any, as the evap line is currently there, and the CEL keeps coming on for the selonoid saying incorrect flow, which leads me to believe I need to connect it back to the throttle body with a check valve for boost.

Also if I connect the inlet to after the map sensor, then that's after the turbo which would cause positive pressure to leak into the valve cover then would it not?

Also any idea why I would have a breather on the bottom of the motor towards the rear of the car?

tofast4u