Catch Cans - Again

[bubba]

The lower port is intended as a drain, to empty the catch can.

I already told you how to hook it up.

[Smity42]

yes but everything else in this thread says you should do the PCV valve as well...

[Bliksem]

Meh.

+1

[bubba]

Meh.

[Neejay]

yes but everything else in this thread says you should do the PCV valve as well...

Simple. Few options here:

#1) PCV valve + exhaust side valve cover -> T-fitting -> catch can -> intake pipe [block intake manifold nipple for PCV]

#2) PCV valve + valve covers (separate hoses) -> catch can -> intake pipe [3 high ports required on catch can; block intake manifold nipple for PCV]

#3) Stock PCV valve setup; exhaust side valve cover -> catch can -> intake pipe

Obviously #3 is the easiest.

[Just_Rb]

ive just bought a catch can and reading through this thread is soo confusing causing everyone has their own method of installation so to make everything much more simpler could the people that have one installed "properly" please post a pic of it installed in your engine bay. this would clear up alot of questions.

thanks

[Checkbuzz]

ive just bought a catch can and reading through this thread is soo confusing causing everyone has their own method of installation so to make everything much more simpler could the people that have one installed "properly" please post a pic of it installed in your engine bay. this would clear up alot of questions.

thanks

Here is my installation, there is a lot of confusing info around but here is my 2 cents:

Most of the catch cans available have only 2 outlets the best and easiest way to set it up is as I have.

No need to block any hoses or frig around with PCV valves etc.

You are not really worried about the crankcase fumes being drawn into the plenum via the PCV under no boost (as in option #1 & #2 above)

You are concerned about the fumes (& oil) going into the intake and through you intercooler (reducing cooling efficiency as oil is a poor conductor of heat) under boost conditions. This can also lower the RON (octane) of the fuel mix and cause detonation... v bad!

So all you need is a 50% plumb back install as I have done (option #3 above)... very easy, simple and takes care of the main issue.

P.S. I filled one side of the catch can with steel scourers caged in with steel mesh screen to help scrub the oil out of the fumes

Edited June 28, 2009 by Checkbuzz

[illusiVe]

check, thank you!! i was thinking of diong the exact same thing and u've said it works and looks safe.. im doin it =D.

all those other diagrams just too damn confusing..

Edited August 8, 2009 by illusiVe

[gotRICE?]

I always wondered if there was anything wrong with the way mine was set up..? (i think i posted the pic earlier.. but here it is again)

PCV is stock because blocking it gave me blowby issues and was getting smoke taking off from lights.. Returning it to stock fixed it. So wont be blocking it again.

Both rocker covers are vented to Atmo via the large catch can. And the line going to the turbo is blocked, although you cant tell, it is. Just makes it look less messy If you look closely at it you can see a black ring, and thats a double ended bung i made from alloy.

Is it absolutely necessary to keep the turbo line connected? I know it aides in sucking the fumes into the can, but air will take the easiest path regardless. And in my setup, that would be VIA the catch can?

Edited August 8, 2009 by gotRICE?

[r33_racer]

You can run two breathers into catch can. run a line through a one way valve from bottom of catch can into the exhaust with the fitting welded on at a 45 degree angle facing against the flow of the exhaust. Bypassing exhaust creates a vacuum in the line and can and sucks any oil/vapours out always leaving the can empty or near enough. One way valve stop exhaust gasses filling the catch can if for whatever reason it backfires up the line instead of bypassing it. Obviously dont use the factory plastic one.

Block off everyother line. Get rid of the pcv line and anyother line that runs into your intake. Only want breathers going into catch can. Dont want any fumes going back into the motor, whether it be manifold or intake of turbo.

[Shaun O]

Hey guys, here is how my catch can is currently setup:

That is how the previous owner set it up, as you can see the PCV valve pipe is still there so you can actually feel the sucking on the catch can vent pipe( the pipe going down towards the rad from the catch can) but i'll be blocking the pcv valve this week anywho. At the moment the catch can is using heater hose but I got some better heat resistant hose to put on this week too, just a quick Q if I do all this while engine is cold it's not gonna spew oil everywhere is it? (replacing the catch can hoses and blocking off the pcv valve that is)

Also another Q is at the moment the catch can vent pipe has no filter on the end but once I block off the pcv valve will I even need one since it will no longer be going into the intake? cheers!

Be interesting to see if the idle is a bit smoother once the afm knows wtf is going on properly since atm it hunts a little bit sometimes.

[GT-RZ]

Hey guys, here is how my catch can is currently setup:

That is how the previous owner set it up, as you can see the PCV valve pipe is still there so you can actually feel the sucking on the catch can vent pipe( the pipe going down towards the rad from the catch can) but i'll be blocking the pcv valve this week anywho. At the moment the catch can is using heater hose but I got some better heat resistant hose to put on this week too, just a quick Q if I do all this while engine is cold it's not gonna spew oil everywhere is it? (replacing the catch can hoses and blocking off the pcv valve that is)

Also another Q is at the moment the catch can vent pipe has no filter on the end but once I block off the pcv valve will I even need one since it will no longer be going into the intake? cheers!

Be interesting to see if the idle is a bit smoother once the afm knows wtf is going on properly since atm it hunts a little bit sometimes.

Your idle will be much smoother once you block that off. Any air going in through your catch can is not read by the AFM and will result in a crap idle... You should still attach a filter as sometimes the engine can naturally create vacuum and you don't want the risk of anything getting in there regardless as it would go straight in to the cam cover (When the PCV valve is blocked off)

PS: If you want to keep the PCV valve connected then you should plumb the line of the catch can back in to the intake AFTER the AFM. Then it is the same as the factory setup but with something to catch the oil.

vent to Atmo = Block off PCV valve

Re-circ = two options...

1, Block off the PCV valve and run a single line from the catch tank to AFTER the AFM

2, Leave PCV valve and run a line ALSO from the catch tank to AFTER the AFM

The setups above that vent to atmo with the PCV valve connected will run fine when on boost because obviously the PCV valve only opens during negative pressure in the intake manifold (idle) But will have noticeable problems when at idle especially on warmer days.

Edited August 10, 2009 by GT-RZ

[gotRICE?]

The setups above that vent to atmo with the PCV valve connected will run fine when on boost because obviously the PCV valve only opens during negative pressure in the intake manifold (idle) But will have noticeable problems when at idle especially on warmer days.

So in theory with my setup (Post #149) at idle when the PCV is open, the engine is getting a little bit of un AFM'd air through the catch can breather?

I do notice that very occasionally when i am parking (using alot of steering with minimal revs) i get a slight rev hunt. It happens so rarely i never think anything of it.

But that would make sense correct?

Edited August 10, 2009 by gotRICE?

[GT-RZ]

So in theory with my setup (Post #149) at idle when the PCV is open, the engine is getting a little bit of un AFM'd air through the catch can breather?

I do notice that very occasionally when i am parking (using alot of steering with minimal revs) i get a slight rev hunt. It happens so rarely i never think anything of it.

But that would make sense correct?

yes. I know at least one person who had done this and got regular stalling until they blocked the pcv valve off.

[gotRICE?]

yes. I know at least one person who had done this and got regular stalling until they blocked the pcv valve off.

Cool thanks.

Have never had a stall ever. And when i really think about it, it only happens at night with the lights on.

I refuse to block the PCV again because of the blowby i was getting. I guess ill live with the ever so rare hunt. And i do also have an SAFC, so ill just tune it out

[Sydneykid]

I refuse to block the PCV again because of the blowby i was getting.

Running PCV doesn't stop the blow by, it's still happening except it's going into the engine instead of breathing out of the catch can. So you are still contaminating the combustion process with oily vapour when the engine is not under boost. Hence reducing the octane of the fuel, fouling up the plugs and the combustion chambers.

I'm very surprised that blow by is problem off boost anyway, because the PCV is closed when the engine is on boost. Which is when 99% of the blow by occurs.

I guess ill live with the ever so rare hunt. And i do also have an SAFC, so ill just tune it out

That won't help, the correction factors vary too much to be able to tune it out. Air con, power steering and electrical load plus ambient temperature and engine temperature are all variables that the SAFC doesn't know about.

There are only 2 ways way to cure it properly, block off the PCV or run the catch can outlet back into the inlet after the AFM and before the turbo. As long as your catch can wroks effectively (ie; separates the oil vapour) then that's not such a bad solution.

Cheers

Gary

[Shaun O]

Your idle will be much smoother once you block that off. Any air going in through your catch can is not read by the AFM and will result in a crap idle... You should still attach a filter as sometimes the engine can naturally create vacuum and you don't want the risk of anything getting in there regardless as it would go straight in to the cam cover (When the PCV valve is blocked off)

Finally got around to doing it this weekend.

Attacked an M10 bolt with an angle grinder, took off the thread and the head to be left with the smooth part

Hacksawed the hose in half in the middle, bolt fits perfectly, smeared some gorilla glue on the bolt piece, put the hose back together, more gorilla glue at the join and then a hose clamp to finish her off

Holy crap the difference in idle is like night and day, amazing, wish I had done it sooner.

[Deano 1]

anyone got any pics of a catch can setup on a rb26?? just want to see how and where u put the hoses and the can?

cheers

[GT-RZ]

Finally got around to doing it this weekend.

Attacked an M10 bolt with an angle grinder, took off the thread and the head to be left with the smooth part

Hacksawed the hose in half in the middle, bolt fits perfectly, smeared some gorilla glue on the bolt piece, put the hose back together, more gorilla glue at the join and then a hose clamp to finish her off

Holy crap the difference in idle is like night and day, amazing, wish I had done it sooner.

You did it the best way too.... looks like it's still connected so the piggas with half a brain won't know the difference. And yea now on idle your computer can read the correct amount of air that's going inside the crunch and add the appropriate amount of fuel! perfect.

[simpletool]

Or you could have glued shut the PCV valve with high temp silicon or similar - that's what I did. totally internal job then But now I need a new PCV gasket anyway.