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Old 02-09-2014, 10:50 PM   #1
MufFiNz
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Default quick question on crankcase venting

Ok getting my motor back together and im just trying to figure out what to do for the crankcase ventilation. The original plan was to plumb two moroso breather cans but that got me thinking. Has any one just ran breather filters on the ports similar to what evo guys and muscle car guys do on there valve covers? I wanted to keep the engine bay as clean as possible and this was one way I thought I could do it. Keep in mind its a sleeved pinned and oringed block with a twin scroll 6466 e85 motor with standalone so im not to worried about cel and stuff like that. Thanks for any input
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Old 02-10-2014, 12:08 AM   #2
jdogma
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Keep in mind that I am just learning about turbos and Subarus, but I built a Turbo EZ30R http://forums.nasioc.com/forums/show....php?t=2494976 I tried the breather filter like the NA V8 guys use. At the track it blew oil out pretty bad (15 psi max boost). It seemed ok on the street. Now I am going to a vented catch can via hose because the breather filter was a fire hazard and a mess. 1st race is this weekend at Barber Motorsports Park. Check my thread next week and I'll indicate if there was a problem with the catch can setup.
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Old 02-10-2014, 12:57 AM   #3
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Well there is no info in your profile so we don't know much. I run a hybrid on 04 cv system. hope that helps
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Old 02-10-2014, 05:50 AM   #4
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Ideally you want to draw vacuum on the crankcase and catch the vapor in the can, but no, you can't simply cap the ports with a breather filter unless you want to blow oil all over the place.
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Old 02-10-2014, 07:18 AM   #5
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ive always wanted to run a vac pump and vent to the dp
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Old 02-10-2014, 07:18 AM   #6
I--RIDE--BIKES
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I'm going to be fabbing my own catch can for my crank case breather. So essentially the can will have one inlet from the crank case, and one outlet that will run to the intake pre-turbo to draw a vacuum on it right? Then a drain valve of course.
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Old 02-10-2014, 07:28 AM   #7
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Quote:
Originally Posted by I--RIDE--BIKES View Post
I'm going to be fabbing my own catch can for my crank case breather. So essentially the can will have one inlet from the crank case, and one outlet that will run to the intake pre-turbo to draw a vacuum on it right? Then a drain valve of course.

you REALLY dont want to suck the oil vapor back into the intake

that is one of the worst things that the emissions controls DO is suck the oil vapor back into the intake
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Old 02-10-2014, 07:30 AM   #8
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Quote:
Originally Posted by I--RIDE--BIKES View Post
I'm going to be fabbing my own catch can for my crank case breather. So essentially the can will have one inlet from the crank case, and one outlet that will run to the intake pre-turbo to draw a vacuum on it right? Then a drain valve of course.
Yes that's the way it's done. I bought my can from Saikou Michi and asked him to do custom port sizes. Works great.
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Old 02-10-2014, 07:33 AM   #9
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you REALLY dont want to suck the oil vapor back into the intake

that is one of the worst things that the emissions controls DO is suck the oil vapor back into the intake
I think he meant between the air filter and the turbo and not the intake manifold. At least I hope he did.
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Old 02-10-2014, 07:42 AM   #10
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Yes I meant between the filter and turbo. Uncle Scotty are you saying that it would be better to vta the outlet port of the catch can? Because I thought it was a good thing that a slight vacuum be drawn on the crank case breather? Furthermore you wouldn't be introducing any oily vapours into the intake system if the catch can is functioning correctly right? Just looking for guidance on my design.
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Old 02-10-2014, 09:01 AM   #11
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Quote:
Originally Posted by I--RIDE--BIKES View Post
Yes I meant between the filter and turbo. Uncle Scotty are you saying that it would be better to vta the outlet port of the catch can? Because I thought it was a good thing that a slight vacuum be drawn on the crank case breather? Furthermore you wouldn't be introducing any oily vapours into the intake system if the catch can is functioning correctly right? Just looking for guidance on my design.
The bolded part is correct.
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Old 02-10-2014, 12:48 PM   #12
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The only way I know of maintaining a vacuum all the time is to run a dry sump pump. The resulting vacuum in the crankcase will help make significant power gains at high rpm and oil will not blow out anywhere.
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Old 02-10-2014, 03:41 PM   #13
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Someone suggested a vibrant slash cut bung in my catch can thread. Rather than using the turbo inlet as a vac source, the exhaust will pull the crankcase gasses.
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Old 02-10-2014, 03:53 PM   #14
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Quote:
Originally Posted by rdieder View Post
Someone suggested a vibrant slash cut bung in my catch can thread. Rather than using the turbo inlet as a vac source, the exhaust will pull the crankcase gasses.
That works very well but technically emissions doesn't like it and if you have cats they will go bad quicker if your getting a lot of blow by.
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Old 02-10-2014, 03:59 PM   #15
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Quote:
Originally Posted by MufFiNz View Post
Ok getting my motor back together and im just trying to figure out what to do for the crankcase ventilation. The original plan was to plumb two moroso breather cans but that got me thinking. Has any one just ran breather filters on the ports similar to what evo guys and muscle car guys do on there valve covers? I wanted to keep the engine bay as clean as possible and this was one way I thought I could do it. Keep in mind its a sleeved pinned and oringed block with a twin scroll 6466 e85 motor with standalone so im not to worried about cel and stuff like that. Thanks for any input
If you put a breather filter over the crankcase vent, you will have a fine mist of oil vapor coming out at all times. This oil vapor will deposit a film of oil all over your engine bay.

I made a vent-to-atmosphere catch can for mine and I have this issue. I'm now redesigning my catch can to have a vac source.

I'm at work now, but I can post a pic showing the proper setup/routing which should simplify things a bit.
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Old 02-10-2014, 04:06 PM   #16
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Rogue, that would be really helpful if you posted a picture. And since we are on the topic, I will also be making a catch can for my heads. Does it make more sense to have 2 inlets into the can (1 from each head), and then do an outlet to the intake to act as a minor vac source just as we had discussed for the crank case catchcan)? Or to have the two breathers "T" together into a single line into the can, then the single line out?
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Old 02-10-2014, 05:36 PM   #17
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edit: My drawing was wrong so I removed it. Read the .PDF I attached instead. It's the best source of CCV/PCV design info I've seen.
Attached Images
File Type: jpg CCV_Bible.jpg (45.2 KB, 9 views)

Last edited by Rogue_P; 02-13-2014 at 03:55 PM.
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Old 02-10-2014, 06:58 PM   #18
MufFiNz
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Ok that helps a little thanks. But one question with the vaccumm hooked up what is the oil vapor get sucked back through the turbo?
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Old 02-10-2014, 11:08 PM   #19
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Quote:
Originally Posted by rdieder View Post
Someone suggested a vibrant slash cut bung in my catch can thread. Rather than using the turbo inlet as a vac source, the exhaust will pull the crankcase gasses.

this is the other best way i can think of....other than a vac pump or real dry sump
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Old 02-10-2014, 11:35 PM   #20
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Quote:
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...if you have cats they will go bad quicker if your getting a lot of blow by.
Install the slash cuts after the catalytic converter(s). Problem solved.
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Old 02-11-2014, 05:15 PM   #21
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Quote:
Originally Posted by MufFiNz View Post
Ok that helps a little thanks. But one question with the vaccumm hooked up what is the oil vapor get sucked back through the turbo?
The actual volume of oil is very little if the catch can is doing its job.
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Old 02-11-2014, 06:32 PM   #22
MufFiNz
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Quote:
Originally Posted by Rogue_P View Post
The actual volume of oil is very little if the catch can is doing its job.
So would you suggest the dual catch can setup or a single. And would have the catch cans with a filter on top help any or would it just not create a vaccum ?
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Old 02-13-2014, 04:09 PM   #23
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Quote:
Originally Posted by MufFiNz View Post
So would you suggest the dual catch can setup or a single. And would have the catch cans with a filter on top help any or would it just not create a vaccum ?
Mine is not currently a 2-can setup. I have a single can with 2 -8AN lines from the valve cover and a single -12AN from the crankcase vent line. It's a vent-to-atmosphere setup and I am not happy with it. I never pull a vacuum on my crankcase with a VTA setup.

I'm building a new can that has dual chambers (2 cans in one). How it will be plumbed is TBD since I've come into new info about the "best" way to design the system for subarus (and airplanes with "boxer" type motors).

I will say this with confidence: Never buy an Air Oil Separator that returns the oil to the crankcase. The oil from blow-by is contaminated with water and fuel and other gunk. This mixture then condenses and settles to the bottom of the can. If you pipe it back to the engine, your oil is now contaminated and will end up causing damage.

I wish I still had the picture of what we emptied from my friends Evo. He runs e85 and we poured the contents of his catchcan into a clear bottle and let it sit. After a while the mixture separated into water/fuel and oil... about 50/50. Pretty nasty stuff.

Since I'm neck deep in researching this, once I've got all the info I'll start a end-all be-all CCV/PCV thread and drop the link in here. FWIW I will be soliciting information and advice from several of the best engine builders and tuners on NASIOC such as Uncle Scotty, Junior, etc.
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Old 02-13-2014, 06:45 PM   #24
MufFiNz
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Thanks
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Old 02-13-2014, 07:48 PM   #25
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Rogue_P
Here is a good idea of what your gunk looked, I'm sure!!
This is only the normal build up that accursed in my drain out trap from my VTA catch can. It's like gravy and never really seperates oil from water. This way accumulated about every 3-4k

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