The way I understand it, under boost the only source of vacuum is at the turbo air filter. Thus, in order to positively vent the crankcase under boost you need to pull vacuum from the air filter.

So if I'm pulling vacuum from there, won't I pull oil into the turbo the same way oil gets pulled into the intake on the stock Pcv system?

 

If the catch can is setup correctly, internally, with baffles or some sort of mesh, the oil will stay in the catch can and not exit out the top of the can and enter the filter area.

so no, it won't pull oil; unless it's full.

 

I guess then I will need to run 2 catch cans because the line from the air filter to the valve cover Is completely independent of the catch can.

Here's a schematic of the set up:

 

I have a big breather cap, like old school valve covers on the passenger side and then a small filter on the driver side. I get lots of oil smell in the cab after boost. I would like to catch some of this and am also unsure how to plumb my ebay catch can.

 

I run a sealed catch can with a check valve between the intake and can. I run the fresh air side to the elbow in front of the turbo. Works rather well. I have about 500 miles with the setup and i have no oil i. The intake elbow before the turbo.

I had a check valve on the clean air side as seen in the puc below but it has been removed



Pic if the Boomba check valve

 

I run mine the same way, sealed can with check valve in between the can and the intake, drivers side goes to the inlet of my procharger, no problems here.

 

If you have a vented catch can why would you run vacuum lines to it? Isn't that the point of it being vented? So you don't have to run vacuum lines.

If its a sealed can then the vacuum would suck out the fumes and not fumes and air around the can.

Do most agree that you have to run two vacuum lines one by the throttle body and one by the turbo inlet to have vacuum at all times?

 

Because I want POSITIVE crankcase ventilation. If you run the lines to the can with no vacuum it's just venting but not sucking the fumes out. In that case, just run breathers on the valve covers.


I just got my can mounted. Yes, it's a vented catch can, but it only vents when the can is under positive pressure. Under vacuum the can is sealed.




And like BlackGMC I tapped my intake filter and am routing it to the passenger valve cover. The TB port is capped off.

 

so your only vacuum source is from your intake filter?

Does the filter on the catch can have a check valve on it? If not how does it only vent under pressure? Also what kind of catch can is it?

If the can is under vacuum how would it ever get positive pressure in it where it would need to be vented.

Sorry for the confusing questions i just cant get this strait in my head.

 

I guess what i previously thought was that the a vented catch can didnt use vacuum that the valve covers just vented to it, but it caught all the oil coming out of the valve covers and kept fumes down.

A sealed catch applied vacuum to the crank case and then burnt the fumes for no smell.

But what you are saying is that they both have to have vacuum and they both burn the fumes. just the vented one will release pressure if there is a loss of vacuum or something.

Just what to make sure i got this right.