Not another Catch Can thread (please help)

[Phyco]

Hey guys... Not a very frequent poster here so bear with me please.

In the process of getting all the varying issues on my R34 sorted before I take it in for tune (boost was previously turned right down as I bed in a new head gasket). One of those 'issues' is with the intake piping, the oil breather line from the crank case is currently not connected to well, anything. It's just hanging down through the engine bay to under the car. Obviously this is not ideal and the tuner mentioned I would want to get some sort of catch can setup before bringing the car in. I don't want to feed the oil line back into the intake which I guess means I'll be venting it to atmosphere. After searching and reading through a tonne of threads on this forum and others I'm still no clearer as to what I need to buy unfortunately, as it seems all catch cans seem to have two inlets whereas I only appear to have one line that needs to be connected. Pic for reference, not exactly an up to date one unfortunately but it shows the line I'm talking about clearly enough. Can anyone advise me on this?

Secondary question, from everything I've read for venting to atmosphere it's said the PCV should be blocked, is there any real issue likely to come from not doing that?

Cheers

[Murray_Calavera]

I wonder if your counting one of the 'inlets' as the port for the vent? All catch can's will have at least 2 ports on them, an inlet and outlet. The outlet either gets a breather on it, venting to atmo as your intending to do. Or it gets a line on it that is connected to the intake to pull a vacuum through the catch can helping it to work better. 

I've attached a photo of a atmo venting catch can to help clear this up. 

If your wanting to keep the PCV valve, you might want to consider getting a catch can with 2 inlets and 1 vent on top. Feed the PCV line and also the red line you've circled to the 2 inlets on the can. Vent the top line to atmo. 

Just wondering, is there any reason you don't want to fit the outlet port back into the intake? 

[djr81]

Doubtless he doesnt want oil back into the intercooler/inlet/engine. 

It doesnt have to be a problem, you just need a decent catch can.  So for what its worth I would recommend this style of thing.

https://www.autopartssupply.com.au/mann-hummel-provent-200-oil-seperator-catch-can-fi

Has a filter, return drain and does the job.  It isnt shiney and anodised so marks off for that.  You can keep your pcv then which means the crankcase may get some vacuum and generally end up with less crap everywhere.

There are different styles without a drain (So you have to empty them periodically). MIshomoto or something similar do one.

If venting to atmosphere the pcv if left on will suck fresh air backwards through the catch can on the engine over run so wont actually do anything useful.

[GTofuS-T]

14 minutes ago, djr81 said:

https://www.autopartssupply.com.au/mann-hummel-provent-200-oil-seperator-catch-can-fi

that's actually pretty nice! OEM appearance too which would be desirable for some applications.

[KiwiRS4T]

Venting to atmosphere is illegal most places but anyway as stated above if you have an efficient catch can you will not be flooding the intake with oil. Connecting to the intake will also promote some negative pressure which will help to ventilate the crank case and depending on how much track work you are doing there should not be too much getting into the catch can anyway.

[Phyco]

Thanks guys for the help so far.

9 hours ago, Murray_Calavera said:

I wonder if your counting one of the 'inlets' as the port for the vent? All catch can's will have at least 2 ports on them, an inlet and outlet. The outlet either gets a breather on it, venting to atmo as your intending to do. Or it gets a line on it that is connected to the intake to pull a vacuum through the catch can helping it to work better. 

Yes I thought this also, but the cans I was looking at with the vent on the top still seemed to have 2 ports anyway. Like there was meant to be two inlets from the crank case where I only have the one (seeing as the two ports already join into one atop the engine). Can I just block one of them up on the can without causing any negative effects as long as it has the breather on it?

9 hours ago, Murray_Calavera said:

Just wondering, is there any reason you don't want to fit the outlet port back into the intake?

Based on advice I've gotten, as my AFM has been moved to the hot side of the intake, and I don't want any potential for oil residue to contaminate it.

 

[GTofuS-T]

6 hours ago, Phyco said:

Like there was meant to be two inlets from the crank case where I only have the one (seeing as the two ports already join into one atop the engine).

Probably to facilitate riced up engine bays like so, 2 braided lines look sexier than 1.

[Phyco]

2 hours ago, GTofuS-T said:

Probably to facilitate riced up engine bays like so, 2 braided lines look sexier than 1.

That is quite a sexy engine bay I have to admit.

Mine isn't winning any beauty awards at the moment but a more updated pic is attached than what I posted earlier.

Thanks for all the advice in this thread anyway, based off that and some other reading I've done I've decided to go for this and will mount under the airbox for extra stealthiness https://www.tuffcarparts.com.au/proflow-750ml-stealth-black-oil-catch-can-tank-wit~13846

[dyl33]

What do you guys think about this catch can?

https://www.supercheapauto.com.au/p/saas-saas-baffled-oil-catch-can-black-billet---st1003/534316.html

[KiwiRS4T]

14 hours ago, dyl33 said:

What do you guys think about this catch can?

https://www.supercheapauto.com.au/p/saas-saas-baffled-oil-catch-can-black-billet---st1003/534316.html

Looks good. Maybe a bit small for a track car but otherwise fine.

[Ben C34]

On 7/17/2020 at 6:16 PM, dyl33 said:

What do you guys think about this catch can?

https://www.supercheapauto.com.au/p/saas-saas-baffled-oil-catch-can-black-billet---st1003/534316.html

a mate has one and they seem ok . I dont like the way the inlet tube goes to the bottom, we chopped it off a bit so there is a gap to the bottom if oil pools in there. The theory being if oil is in the bottom any blowby will bubble that up like crazy, and so long as you are below that lowest baffle it is doing it's job. Also put some coarse steel wool in top layer, but to be honest car doesnt put anything into the can anyway so cant comment if any of that was worthwhile.

[dyl33]

Thanks man ill keep that in mind about the inlet tube.

It looks as good as any mishimoto can. But the more i research the more i have no idea if they are even needed.

[KiwiRS4T]

4 hours ago, dyl33 said:

Thanks man ill keep that in mind about the inlet tube.

It looks as good as any mishimoto can. But the more i research the more i have no idea if they are even needed.

if you are asking the question you don't need one!

[dyl33]

Maybe

[joshuaho96]

On 7/6/2020 at 6:08 PM, GTofuS-T said:

that's actually pretty nice! OEM appearance too which would be desirable for some applications.

Mega thread bump but I found an SAE study where someone actually bought a ton of air oil separators and catch cans and tested them to see their pressure drop with respect to flow rate and filtration efficiency. The ProVent had comparable pressure drop to the catch cans with mesh/filtration media in the 50 mbar range when wet while achieving dramatically higher filtration efficiency. Crankcase ventilation seems to be a major problem with the RB and I suspect having the right kind of crankcase filtration will go a long way to helping things.

[The Bogan]

On 22/08/2022 at 6:31 PM, joshuaho96 said:

Mega thread bump but I found an SAE study where someone actually bought a ton of air oil separators and catch cans and tested them to see their pressure drop with respect to flow rate and filtration efficiency. The ProVent had comparable pressure drop to the catch cans with mesh/filtration media in the 50 mbar range when wet while achieving dramatically higher filtration efficiency. Crankcase ventilation seems to be a major problem with the RB and I suspect having the right kind of crankcase filtration will go a long way to helping things.

Linky to study please 🙏

[joshuaho96]

On 8/22/2022 at 1:39 AM, The Bogan said:

Linky to study please 🙏

https://sci-hub.se/https://doi.org/10.4271/03-12-01-0001

Methodology to me seemed sane, up to you whether you believe the Q factor metric they used to decide the best performing though.