Oil catch can, Help needed.

[my98GST]

Alright, I've got this Greddy catch can. I also have a FP 4" intake without the nipples on the intake pipe. My question is. Do I take the valve cover line into one port, then do I install a barb valve cover and then block it off, and then take another line from the other nipple on the catch can, install the PCV valve in to the line and plug it back in to the intake manifold?

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How would I do this for the JMF SMIM?

 

[turbosax2]

As long as the catch can is not vented to atmospere, no, except the fact you will get slightly better filtration with the linked catch can. They're both catch cans, one is just bigger (and bling bling) but empty (which relies on gravity alone for filtrations) and the other us smaller but with built in filter element.

http://www.z06vette.com/forums/printthread.php?t=73303
In that link, the guy takes out the filter. Do you keep those filters in? If you get a chance and don't mind, please post pics of your setup. Thanks!

 

[oldman]

http://www.z06vette.com/forums/printthread.php?t=73303
In that link, the guy takes out the filter. Do you keep those filters in? If you get a chance and don't mind, please post pics of your setup. Thanks!

I kept the filter element. My ex still has my camera, what is it that you need to see? It's pretty straight forward really. Here are some pictures I took last year for someone else but it's the breather side, I like the fact that it's so light that I can just suspend it in mid air with the attached hoses.

http://www.dsmtuners.com/forums/showpost.php?p=50425778&postcount=413

 

[turbosax2]

Thanks! One more question - what kind of check valve do you use and where can I find a good one? I have no experience with them.

 

[oldman]

http://www.dsmtuners.com/forums/showthread.php?t=229338

 

[bmxrider154]

I've skimmed through this thread and have one question to clear things up. I always thought the catch can was to be vented so that's what i've always done.

So, if the vent is not re-routed to the intake pipe, is it alright to cap the other end of the 'Home Depot" can off so it's totally sealed? I currently just run my vent to the underside of the car, which makes a mess obviously.

 

[turbosax2]

Oldman, thanks for all your help. How often, if ever, do you have to replace the filter in the catch can? Can they be cleaned at all?

 

[oldman]

So, if the vent is not re-routed to the intake pipe, is it alright to cap the other end of the 'Home Depot" can off so it's totally sealed? I currently just run my vent to the underside of the car, which makes a mess obviously.

No it's not OK to just cap it off, you will no venting outlet when under boost (when you get most blow by) causing excessive crankcase pressure. The reasons why it should reroute back to the intake pipe are:

1. To utilize vacuum in the intake pipe created by the spooling turbo and actively pull pressure and blow by out of the crankcase.

2. To supply fresh, metered and filtered air to the crankcase when PCV opens while the intake manifold is under vacuum.

Problems with your current setup (VTA) are:

1. Passive venting without vacuum will never be as good as active venting using the intake pipe.

2. You are pulling in unmetered and unfiltered air when PCV opens.

Oldman, thanks for all your help. How often, if ever, do you have to replace the filter in the catch can? Can they be cleaned at all?

No problem, the filter is a 5 micron filter I have not change or clean the filter since I had them, I simple blow through it every time I empty it to make sure it isn't clogged.

 

[bmxrider154]

Ok, I didn't think that would be right.

I never thought about the air entering through the vent. I never really took the time to learn how the whole system worked.

I'm probably going to look into tapping my intake pipe and route it the way it's suppose to be here soon. I do like the idea of the 'home depot' catch can but I would like to hide it so it can't be seen. I'm pretty picky when it comes to my engine bay. Thanks for the little bit of information, learned something today.

 

[oldman]

I never thought about the air entering through the vent. I never really took the time to learn how the whole system worked.

Here you go. http://www.autoshop101.com/forms/h63.pdf

 

[bmxrider154]

Thanks, very informative link.

 

[oldman]

No problem.

 

[bmxrider154]

Well, I installed a "catch can" today on the breather side. It's temporarily mounted now, need to make a bracket for it to hide it. I also ordered a few of the good check valves for the Pcv side and need to figure out a way to cleanly install one of the "catch cans" there as well. I thought about mounting it underneath the manifold or even on the firewall, but that would be a decent amount of hose. So I'm not sure yet. I included a two pictures of my install.

Don't mind the duct tape, the damn coupler stretched.

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[oldman]

I must be getting old because I don't see a catch can anywhere!!

edit: Nevermind, it's by the fuse box, I'm getting old.

 

[bmxrider154]

Haha, it's hard to see in the first picture, so you're alright.

 

[95CarbonEclipse]

I must be getting old because I don't see a catch can anywhere!!

edit: Nevermind, it's by the fuse box, I'm getting old.

No kidding... i was staring at it forever trying to figure out what was going on there.

BMXrider, I think more importantly though you should install a catch can on the PCV line... MAKE SURE you get a decent check valve FIRST though. IMO more oil is sucked up through the PCV valve as compared to the breather hose, mainly due to boost/vacuum pressure. Right Oldman??

 

[romeen]

BMXrider, I think more importantly though you should install a catch can on the PCV line... MAKE SURE you get a decent check valve FIRST though. IMO more oil is sucked up through the PCV valve as compared to the breather hose, mainly due to boost/vacuum pressure. Right Oldman??

We were just discussing this in another thread recently. Of course a catch can on both lines would be ideal. But if having to choose one then it would probably be wiser to run the catch can between the VC and intake pipe. The rationale being that oily buldup in the intercooler will probably affect performance more than buildup in the IM.

Also, oily vapors going through the intake pipe can make their way downstream giving the TB a nice coating and then into the IM getting it messy anyway.

 

[Calan]

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I've been reading you guys' thread on this and have a similar setup to bmxrider with a GM MAF in blow-through.

Isn't his PCV still pulling unmetered air through the VC breather at vaccum, since it's before the MAF in this setup?

Or am I missing something here... (it happened once before ... back in 1986 I believe )

EDIT:

I just have the stock PCV and a catch can with breather on the VC intake side; this would explain my always lean idle now that I think about it. (When my car was running and not on stands for major work that is)

EDIT #2:

And... I wonder how much this contributes to the oh-so-common partial throttle "phantom" knock... if you're always sucking in unmetered air (before blow-through MAF..through VC vent.. through PCV) at vaccum conditions, you are effectively always running lean until you hit boost.. correct? Hmmmmmm

Seems logical... and it's a very hard vaccum leak to find/recognize if you are in a blow-through configuration and don't understand the PCV system.

Now I can't wait to get my car back together and experiment with this

 

[romeen]

I've been reading you guys' thread on this and have a similar setup to bmxrider with a GM MAF in blow-through.

Isn't his PCV still pulling unmetered air through the VC breather at vaccum, since it's before the MAF in this setup?

Or am I missing something here... (it happened once before ... back in 1986 I believe )

EDIT:

I just have the stock PCV and a catch can with breather on the VC intake side; this would explain my always lean idle now that I think about it. (When my car was running and not on stands for major work that is)

You know, I have never thought about this in the context of a blow through setup. But it seems like you would be right. If the air being introduced into the system is pulled in before the sensor and ultimately delivered into the intake after it then it is not being picked up by the sensor. That air is basically taking a detour around the MAF. Unless I too am missing something. Since I'm not using a GM MAF (and have no desire to) I really don't follow related threads. I would think this has all been discussed before.

You do have my curiosity up now.

 

[Calan]

Yeah... I've read like 213453123123 threads on phantom knock, partial throttle knock.. etc etc. But I never put it together until reading you and Oldman's threads on the PCV, and I've never seen anything until now about that very well hidden (but substantial) vaccum "leak".

I bought the car with the GM MAF on it, and a breather stuck in the VC. I replaced the breather with a catch can to avoid the oil spray, but still didn't connect the dots as to the unmetered air.

Now it seems to make sense. I've always idled lean, no matter what I do with the MAF-T, and knock is worse until I hit boost, at which point I was able to tune it out with the MAF-T, AFPR, etc. But nothing I did would richen things up at idle... well.. almost nothing. I could add fuel pressure or max the Idle setting on the MAF-T which would eventually overcome the unmetered air (and usually screwed things up in other ways)... but it took alot of tweaking. And it always seemed like the ECU just wasn't quite "right" on the trims.

I wonder if anyone else with a blow-through setup and knock below boost... has tried anything related to this? Would be interesting to see.

 

[romeen]

I'm not very knowledgable regarding the MAF setups but if it is configured in a draw/pull through setup then all the air should be metered, correct? If that's right then it would be interesting to collect some data (take a poll) of how common these issues (PK, lean idle, etc.) are with guys using the blow through setup vs guys who have it setup the other way.

 

[95CarbonEclipse]

Now that you mention it, i've taken a second look at the picture and realize that he is venting the VC pre-MAF.

[Long Pause, thinking about how it should be]

...WOW, even sitting here thinking about how it needs to be ran, i just realized (i think) what it was exactly that you guys are talking about. I was thinking that as long as the VC breather tapped into his IC pipe after the GM MAF that he would be good. But then, thinking about how the PCV system works, it needs the be on turbo inlet side in order to create the correct vacuum for the PCV system to work as it was intended, but that's pre-MAF as well.

I don't know how you could fix this, any ideas??

 

[Calan]

You'd basically have to tap off of the throttle body elbow, which is post MAF. You would be taking fresh, metered air and using it to route through the VC for the PCV to suck on when at vaccum.

I think....

EDIT:

Nope... this won't work either, because you wouldn't be venting the CC at boost. You almost need some type of arrangement that selects post GM MAF for vaccum, and pre-turbo or atmosphere when under boost. A couple of check valves would probably do it. I gotta ponder this a while

 

[snox135]

Maybe I'm wrong but it shouldn't matter if you are using a MAF or stock MAS. If you have the PCV install to the intake and you have the other VC line vented to the atmosphere you will be pulling in unmetered air.

 

[Calan]

Correct snox... that is what we are talking about. If you read back some (and in another thread about the PCV)... this started with a point by Oldman (and a smart one) that the VC shouldn't be vented at all, but rather tied back into the intake line to avoid unmetered air during vaccum.

The point is that if you are in a blow-through setup, then even this could be a problem, depending on where you tie in.

 

[snox135]

Correct but the other VC port needs to be pre turbo to vent the crankcase under boost. So you either plug this port or put some type of catch can or filter media inline with it. I would not suggest plugging it. I know others have done this, but under boost is when crankcase pressure is the greatest.