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Old 03-19-2006, 03:28 PM   #51
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nice write up, thanks
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Old 03-24-2006, 02:02 PM   #52
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Quote:
Originally Posted by spoolinsuby
How does boost get in the system?
I'm curious about this too, since I have a Perrin inlet pipe, and that requires the crankcase vent be teed into the valve cover vents.
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Old 03-31-2006, 04:44 PM   #53
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i don't no about anybody else but im confused about the original write-up. the 2 ways to install the catch cans are throwing me off. first of all there is a "T" inbetween the turbo inlet pipe, the pcv valve, and the crankcase vent.
in the first instruction it says to go from the pcv valve to the can, and from the can to the inlet pipe. it sounds like that way of installing the can this way you are not venting the crankcase at all. i take it that the second install is for the valve covers.
the second thing that is throwing me off are the picturs of the sti from WolfPlayer. it looks like the catch can on that car goes from the crankcase vent under the turbo, to the can and back to the inlet pipe, completly bypassing the pcy valve.
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Old 03-31-2006, 04:50 PM   #54
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the way that i thought you hook it up is running a line from the crankcase vent underneath the turbo to the can, and a line from the can to a "T" that goes to the pcv and the turbo inlet pipe.
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Old 04-08-2006, 05:55 PM   #55
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OK, So i see more and more people going with the dual catch can setup now, so heres what I need to ask...

Why? A good catch can is supposed to be baffled inside which should seperate the oil from the air. Is that the only reason people have for this?

Also, how are you guys plumbing them? breathers to catch can to catch can to intake I guess?

I was planning the compressor filter version so it could filter out contaminants, based on teh above questions do you guys think I should do 2 of these things?
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Old 04-08-2006, 06:25 PM   #56
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....ej25x = 2 catch cans

....ej205 = 1 can
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Old 04-08-2006, 07:25 PM   #57
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Quote:
Originally Posted by Uncle Scotty
....ej25x = 2 catch cans

....ej205 = 1 can
Why oh master of cocktails

Im just curious as to the reasoning. Does the ej25 have more vents or something, I have yet to look at it under the hood but I thought it was the same amount. Or is there suspicion/proof that it needs 2 for some strange reason...More blowby perhaps?
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Old 04-08-2006, 07:58 PM   #58
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Quote:
Originally Posted by jetfan8178
Why oh master of cocktails

Im just curious as to the reasoning. Does the ej25 have more vents or something, I have yet to look at it under the hood but I thought it was the same amount. Or is there suspicion/proof that it needs 2 for some strange reason...More blowby perhaps?

yep....and thus different routing of the PCV
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Old 04-08-2006, 08:53 PM   #59
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Quote:
Originally Posted by Uncle Scotty
yep....and thus different routing of the PCV

Dammit!!!

I hate having more work to do.
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Old 04-09-2006, 02:09 AM   #60
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With a EJ257 there is a way to use a single catch can, but it is a bit much to explain, I'll post a pic in the morning.
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Old 04-09-2006, 02:32 AM   #61
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Old 04-10-2006, 01:25 AM   #62
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Has anyone actually tried running crankcase vent hose into breather cover hose on passenger's side similar to what Perrin turboinlet has (by using a "T")? I am thinking about doing that... any thought on this? will stock turboinlet valvetrain line effectively work with valvetrain and crackcase vents going into that line together? This will be a very simple mod where only thing you need is "T" and 1/2" hose (about 12")...

Is there a reason why Subaru engineers put two inlets on turboinlet hose? If there is a technical reason for it, then I wonder why Perrin engineers decided to join two lines together.
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Old 04-10-2006, 01:16 PM   #63
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Quote:
Originally Posted by txl146
Is there a reason why Subaru engineers put two inlets on turboinlet hose?
I figured that there was a good reason, so I didn't second guess it. I just got through installing two catch can systems - 1 for the valve covers (mounted in front of the battery), and 1 for the crankcase (mounted in place of the windshield washer reservoir).
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Old 04-10-2006, 08:41 PM   #64
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jac04, post a picture!
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Old 04-12-2006, 10:07 AM   #65
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Here you go. I added internal baffles to the GReddy catch cans;


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Old 04-19-2006, 06:48 PM   #66
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Hi guys I posted this on another forum and I was also going to post a new topic in here but I thought this sounded like the right place for it to be.

This topic has been discussed many times on different forums and never really seams to end with a solid answer. I have seen many catch cans installed and it seams everyone is doing it there own way. I will describe how I believe everything works and how I think it should be done. Please offer any input so we can try and get a solid way of installing.
This is the OEM drawing


I believe the correct way is to install two catch cans one for the crankcase and one for the rocker covers. Some people have installed one catch can with two inlets and one outlet, but I donít think this will work correctly as the pressures and direction of flow differ from the crankcase and rocker cover.
While off boost, there is little or no piston blow-by and a negative pressure in the inlet manifold, this causes air to suck in through the rocker cover breather, out the crankcase vent, into the inlet manifold via the PCV.
While on boost, there is more piston blow-by, thus more crankcase pressure, this pressure reverses the flow of the rocker cover breather and forces the vapours back out into the intake before the turbo, the crankcase also ventís into the intake before the turbo as the PCV is forced closed by the positive inlet manifold pressure. If you have and older engine or are running higher boost, you will have more piston blow-by, thus the more the rocker cover and crankcase will vent.

Note; you also need to have some type of gauze inside your catch can to help trap the oil.

IMO this is the correct way to hook them up.


Others have suggested doing the crankcase like this: This is easier to hook up, but IMO you would still get some oil in the intake while the PCV is open.
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Old 04-19-2006, 08:07 PM   #67
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My version of 2 catch can setup

OEM hose vs. Catch can (plus hoses)



Yes, it will clear hood liner.


Two catch cans ($13 vs. $3)
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Old 04-19-2006, 09:04 PM   #68
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I like the filter idea, I think it'll work well
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Old 04-19-2006, 09:48 PM   #69
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Quote:
Originally Posted by wrxbox
I like the filter idea, I think it'll work well
I guess my setup is close to 2nd diagram you posted above with an exception of valvetrain catch can.... yes, I agree that first diagram is more difficult to install.
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Old 04-19-2006, 10:24 PM   #70
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I think 2nd diagram needs to be corrected... under boost, direction of flow inside crank and rocker cover hoses should reverse.


Last edited by txl146; 04-19-2006 at 10:30 PM.
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Old 04-19-2006, 10:29 PM   #71
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I believe this is exactly how my dual catch can is set up...


Last edited by txl146; 04-19-2006 at 10:44 PM.
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Old 04-19-2006, 10:56 PM   #72
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Quote:
Originally Posted by txl146
I think 2nd diagram needs to be corrected... under boost, direction of flow inside crank and rocker cover hoses should reverse.

I didn't worry about the direction of flow in that diagram, as I was only illustrating what I believed to be the wrong way to put in your catch can.
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Old 05-13-2006, 07:34 PM   #73
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so now let me ask a more difficult question.

i have a rotated mount gt35r turbo, with no subaru intake tract, just a k&n filter on the turbo inlet. No maf, running map.

right now i have the 2 lines from the heads connecting to each other, there not venting anywhere.

and i have the pcv valve hooked up to the block, but the other spot which is supposed to goto the intake track is blocked off (becuase i have no intake tract).

so how should i do this with no subaru intake tract before my turbo ?
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Old 05-14-2006, 11:07 AM   #74
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bump for answer
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Old 05-15-2006, 09:51 AM   #75
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x 2
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