Confused. Vented or sealed catch can?
Confused. Vented or sealed catch can? Ok im confused, i keep reading. And i get more and more confuse as i read. I think i want a vented catch can. but then im not sure. I also have seen lots of diagrams on how to hook them up witch make it more confusing because they are different. For now. Im just using it on a stock bottom ls1 with f1a. around 8psi i hope. but plan on building an 408 after and running more boost. so only want to do this one time... thanks for the feedback.
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
It's impossible for any catch can to work if it cannot breathe. In much the same way if you close your mouth, you cannot breathe ( forgetting the nose of course )
And there must be a thousand different guides here if you search.
And there must be a thousand different guides here if you search.
Yes there are a thousand different guides on here. That's what makes it confusing because the run them different ways. And i know it has to breath, But some seems to use a catch cant that has a filter on top. Then some pull from a vacuum source and have no filter on top of the can.
I am running a vented catch can that just catches the oil vapors that are pressurized in the crankcase. I know a lot of people that have a catch can that has a vacuum back to the intake, but I don't like the idea of sucking oil vapors into the intake, I just feel that it coats everything with oil including the plugs.
Remove all the pcv crap and just run a hose from each valve cover to a vented catch can. I use two. Then block off the two ports at the intake and your all set. I mounted my cans down behind my headlights to avoid any smell, as its a daily driver.
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If you take anyone's advice on the PCV system take his.
Still a good idea to use one with the ls6 style whether you're boosted or not. Just ask someone with a z06. It's an overall better design but you still get oil vapor and a good can will help remove more of it, which is after all, why you use one.
Thanks for the feedback all. Im thinking Im just going to go with one with a filter. Witch is also called a Breather tank right? And just run lines from both valve covers to it. Now the next question.. Are they all the same? or is there some better and why? thanks
The only reason to vent to atmosphere is if you can't plumb a system to keep up with excessive blow by. If you have blow by bad enough that you can't plumb a PCV system to keep up you have larger issues than a pcv system is going to fix. A dual can PCV system with the proper connection points and hose sizes, filter media, will work properly and evacuate the crankcase under all conditions. You are basically using manifold vacuum below atmospheric and intake tract vacuum behind the air filter when manifold pressure is above atmospheric (and airflow/vacuum through the intake duct is higher).
The only reason to vent to atmosphere is if you can't plumb a system to keep up with excessive blow by. If you have blow by bad enough that you can't plumb a PCV system to keep up you have larger issues than a pcv system is going to fix. A dual can PCV system with the proper connection points and hose sizes, filter media, will work properly and evacuate the crankcase under all conditions. You are basically using manifold vacuum below atmospheric and intake tract vacuum behind the air filter when manifold pressure is above atmospheric (and airflow/vacuum through the intake duct is higher).
On The Tree
Joined: Feb 2010
Posts: 123
Likes: 0
From: Topeka, KS
Sorry to bring this back from the dead, but out of all the thread's i've read tonight, this one makes the most sense.
So let me get this right, you can run a hose from the 1 drivers side valve cover port, and the 2 passenger side valve cover ports into a catch can. Then you just vent the catch can into the atmosphere?
I'm with you guys in saying, i don't want the air inside the crank case to be sucked back into the intake. Even if the catch can is catching all the oil vapor and mist.
So let me get this right, you can run a hose from the 1 drivers side valve cover port, and the 2 passenger side valve cover ports into a catch can. Then you just vent the catch can into the atmosphere?
I'm with you guys in saying, i don't want the air inside the crank case to be sucked back into the intake. Even if the catch can is catching all the oil vapor and mist.
A catch can alone is not a PCV system it does nothing except collect oil that would have splashed out your breathers if they were on the engine. A relocation of the breather is all it is.
If you dont want the gasses back in your engine run them out the exhaust. I just used the factory check valve off the air pump system and attach it the sealed catch can. It constantly generates vacuum to the canister.
If you dont want the gasses back in your engine run them out the exhaust. I just used the factory check valve off the air pump system and attach it the sealed catch can. It constantly generates vacuum to the canister.
Vented and it better be good especially on E85. Just made this video the other day. This is from ~150 miles of street/hwy driving on E85 with the now cooler temps. I have 2 10an lines into this tank. In the warmer weather double the miles and you'll get the same moisture in it. Definitely don't want this in your oil
