Catch Can FAQ

[ITS_SOY]

Originally Posted by joek92

Saw the perfect configuration at IA and now running it.

Dual can
1. T in from valve cover breathers, out to turbo inlet
2. In from crankcase, out to pcv

This requires relocating the pcv itself. Unfortunately there are a bunch of random hose diameters. But it's the only way to filter everything.

Would you have pictures of this setup?

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[joek92]

Yes, behold this ms paint masterpiece.

[Prosport Gauges]

That's impressive

[joek92]

Originally Posted by Prosport Gauges

That's impressive

Thank you. Can't take credit for the idea, saw it on a white hawkeye at Import Alliance Atlanta. Smart guy.

[Jonahhaddad1]

Looks like the main benefit of that system is that the pvc valve is after the catch can which would keep the pvc valve cleaner?

[joek92]

Originally Posted by Jonahhaddad1

Looks like the main benefit of that system is that the pvc valve is after the catch can which would keep the pvc valve cleaner?

Because the pcv has 2 outlets, this is the only way to filter both using one can.

That allows the second can to be used for valve cover breathers or whatever.

[jj94auto]

Could someone help me create a catch can setup for an 06 ez30d Tribeca? I know it is naturally aspirated. I am getting a pretty bad plume of blue smoke at startup and would like to at least eliminate that.

I know that if I am getting blowby I have much more to worry about bla bla bla.

Anyways, could you all please help me with a setup?

Thank you!

[Hoon Goon]

A catch can won't help start up smoke from worn rings or valve guide seals.

All an NA car needs is a single two port can between the PCV line and intake manifold.

[joek92]

Correct, or between the block and pcv if it has 2 outlets. Sorry that might be hard to understand without pics.

[jj94auto]

Thanks guys. There are 2 ports on it. My research shows that all I need to do is install 2 catch cans. One coming off the PCV to wherever it goes, and one coming off the breather right next to the PCV to wherever it goes.

Under what circumstances would a catch can stop smoking at startup? I have read that it can, but just wasn't sure *when*. I mean the cans will at least serve as a nice diagnostic tool.

[joek92]

Originally Posted by jj94auto

Thanks guys. There are 2 ports on it. My research shows that all I need to do is install 2 catch cans. One coming off the PCV to wherever it goes, and one coming off the breather right next to the PCV to wherever it goes.

Under what circumstances would a catch can stop smoking at startup? I have read that it can, but just wasn't sure *when*. I mean the cans will at least serve as a nice diagnostic tool.

If there is a bunch of oil in the throttle body or intake tubes. Which means it would either come from crankcase or valve covers.
Now, I don't know what problems cause the oil/coolant vapor concentration to be higher in either. I assume that something is getting into the combustion chamber, so a catch can would rule out anything coming through intake valves. The other points of entry are piston ring and head gasket. My old sti smoked on start up, cyl 3 had 90 psi compression.

Recommend doing a leak down test. Not too hard and will properly identify the issue.

*whatever is leaking, it seals after the engine warms up... thermal expansion. Hope that helps.

[bmxhotsauce]

anyone have any photos of a dual catch can set up on car that have no PCV valve ? do you just hook 1 to the crank case to intake then the other 1 to the breather ports on the heads and intake ? thank you

[jj94auto]

Originally Posted by joek92

If there is a bunch of oil in the throttle body or intake tubes. Which means it would either come from crankcase or valve covers.
Now, I don't know what problems cause the oil/coolant vapor concentration to be higher in either. I assume that something is getting into the combustion chamber, so a catch can would rule out anything coming through intake valves. The other points of entry are piston ring and head gasket. My old sti smoked on start up, cyl 3 had 90 psi compression.

Recommend doing a leak down test. Not too hard and will properly identify the issue.

*whatever is leaking, it seals after the engine warms up... thermal expansion. Hope that helps.

It does help.

Well I finally got around to installing 2 Ebay VMS style baffled catch cans. The one from the PCV is filling up very quickly, but it *seems* to have stopped the blue smoke at startup so ignorance is bliss for me.

Any way to run the drain of the can via tubing outside of the frame so that it doesn't fill up so fast...strictly for offroad use...COUGH COUGH or alternatively outside the frame with a valve so that I could empty it easier than having to dismount it every 300 miles?

[Hyper]

on right, there is this thread..

has anybody tried to drain a catch can/aos into the turbo oil drain?

[methaddict]

Originally Posted by bmxhotsauce

anyone have any photos of a dual catch can set up on car that have no PCV valve ? do you just hook 1 to the crank case to intake then the other 1 to the breather ports on the heads and intake ? thank you

I'm using the Radium Engineering standard catch cans. One hose from the crank case to one catch can. A hose on each breather port of the left and right valve covers T'd together to another catch can's inlet port using the oem steel pipe but a T fitting near the windshield wiper reservior. Then I have both exit ports from both cans Y'd together ran under the car all the way to the rear next to the muffler. On the dyno at high boost, a blowby gunk spits out of the end of this hose.

[kris142b]

Originally Posted by 2002Dubx

Easiest way to run it is below. It's not all that hard really.

what is the direction of flow for that setup across the crankcase vent cross over tube

[joek92]

Originally Posted by jj94auto

It does help.

Well I finally got around to installing 2 Ebay VMS style baffled catch cans. The one from the PCV is filling up very quickly, but it *seems* to have stopped the blue smoke at startup so ignorance is bliss for me.

Any way to run the drain of the can via tubing outside of the frame so that it doesn't fill up so fast...strictly for offroad use...COUGH COUGH or alternatively outside the frame with a valve so that I could empty it easier than having to dismount it every 300 miles?

Don't drive with the drain open or it won't pull a vacuum & you'll have a post-MAF leak. (unless I took it wrong)
Vacuum sucks out fumes when there isn't enough pressure to push them out.

[pcampbell]

I'm trying to figure out how to set this up on a supercharged EJ253 .

Obviously the 2 stock breathers that go into the intake can't be there because they would be pressurized. I assume these go to a catch can (vent/intake to/from atmosphere OK?). I've read that this air needs to be metered going into the breathers, so how can we do this with a blow through supercharger?

What about the PCV.. Do I need a separate catch can that sits in between the PCV and the intake manifold?
Will the PCV even work properly, since it will mostly be operating under boost instead of vacuum?
help!

[Booki]

I have a 2009 SH XT Forester.

Picked up two catch cans for a dual setup, but got a bit confused on how to actually plumb it up correctly.

There is a mishimoto YouTube video, but it confused the hell out of me....

Has anybody installed a catch can and can give me some pointers or advice on how to plumb them up ?

[Vancouver98STi]

Originally Posted by Booki

Has anybody installed a catch can and can give me some pointers or advice on how to plumb them up ?

As you might imagine, there is a ton of mis-information on catch can installation on the 'net. It's apparent a lot of people have no idea how the PCV and breather system work.

I installed two oil catch cans on the EJ20K in my '98 JDM Impreza STi wagon. I'm very pleased with how well it all appears to function. I don't know how different your Forester's breather system might be from what I have, but you can have a look at this thread HERE where I was involved in a discussion on this topic.

[fleezy]

do you need 3/8s fittings on the catch can?

[Vancouver98STi]

Originally Posted by fleezy

do you need 3/8s fittings on the catch can?

I found this image online of what I used, Watts A-385A (1/2" ID x 3/8" MIP)... which meant I also had to re-tap the threads (3/8NPT18) in the catch cans.

[KCRS01]

Just quick question. if i were to vent a catch can/air oil separator i would need a tune right since im still using MAF? but when i switch to Speed density i wouldnt need one at all?

[Vancouver98STi]

Originally Posted by KCRS01

if i were to vent a catch can/air oil separator...?

What's the benefit of venting a catch can/air oil separator?

[KCRS01]

Originally Posted by Vancouver98STi

What's the benefit of venting a catch can/air oil separator?

when you use a closed loop system the oil just recirculates in the system, meaning, if it has dirt/contaminants it just go back to the engine.

while vent to atmosphere AOS vents the oil going to the pipe and going to the street. the dirty oil in the system is then completely removed and not recirculated.