catch can pulling vacuum from turbo inlet?

[et89]

You DO have vacuum under boost - there are two channels at play in a boosted PCV system. One during high vac. situations and one during boost/low vac situations.

You are simply wrong about "even a great filter/baffle system will pull oil through" why would a proper system coat your intake system in oil - if it DOES, you have a problem with blow-by that no system can fix or you have an indaiquate PCV system with a oil separator that obviously isn't working correctly.

I really don't understand why you seem to think that you cannot have a high performance recirculated PCV system. OEM's do it all the time - the aftermarket has done it as well.

So what you are saying: when out of boost: you have vacuum in the manifold, so you use that. when in boost, you use the turbo inlet for vacuum assist, with a check valve that controls the airflow to either the turbo inlet or manifold.

[pbonsalb]

OEM's do it all the time - the aftermarket has done it as well.

I understand OEMs use PCVs; I bought my first turbo car over 30 years ago. OEMs don’t triple stock power. The aftermarket is full of catch cans that it says everyone needs because the stock pcv systems are inadequate. Some are better than others. Even good ones pass oily vapor, though they do trap oil. I have the Burger baffled can and it passes oily vapor without even being attached to a vacuum source that would suck even more through. It gets great reviews but maybe it is junk.

I have looked at others in the past, like the ProVent. I think I recently saw an aftermarket dual can system, so perhaps there have been developments. Maybe you could list a few that you have found to pass no oil on 600 rwhp turbo M/S5x running 20+ psi, along with details of how you have plumbed them. If you ask the 600+ rwhp people here, you will find next to none using recirculating catch cans. Hopefully we can learn from your experience with this sort of power on this platform.

[NOTORIOUS VR]

So what you are saying: when out of boost: you have vacuum in the manifold, so you use that. when in boost, you use the turbo inlet for vacuum assist, with a check valve that controls the airflow to either the turbo inlet or manifold.

Correct - also normally there is a limiting valve inline for the boosted side as well (in OEM applications anyway since the inlet side on boosted applications usually have a higher restrictions from the air filter onward which = more vacuum then say a 3" with a k&n on the end).

I understand OEMs use PCVs; I bought my first turbo car over 30 years ago. OEMs don’t triple stock power. The aftermarket is full of catch cans that it says everyone needs because the stock pcv systems are inadequate. Some are better than others. Even good ones pass oily vapor, though they do trap oil. I have the Burger baffled can and it passes oily vapor without even being attached to a vacuum source that would suck even more through. It gets great reviews but maybe it is junk.

Some oily vapor is completely normal and manageable and won't do much if anything in determent in combustion performance opposed to no filtering and getting actual oil droplets in your intake stream which means your system just isn't up to the task.

I'd like to know why you think that tripping stock power causes issues anyway? There is zero reason for that to be an issue. Are people building motors so loose for completely manageable power levels that they need to worry about that? Then that again is not an issue to be dealt with for a recirculated PCV system.

The Burger can "looks" like a Chinese part that costs $20 USD so I cannot speak too much on that part but if you are getting oily splatter on the outlet of it vented to ATM. maybe the can just doesn't work right or possibly it's just not the right can for venting use cases? I have an aliexpress version of that can - I never got around to installing it but I can see that since it's just a bunch of holes that try to keep the oil splatter out of the return past a certain level of CC flow and also oil content in the can it would likely splash back up to the return. FWIW, that can design isn't an oil separator but rather a catch can with limited separation abilities IMO - vs what I've listed below and OEMS which normally use s centrifugal force to separate the oil droplets from the vapor that would be returned.

I have looked at others in the past, like the ProVent. I think I recently saw an aftermarket dual can system, so perhaps there have been developments. Maybe you could list a few that you have found to pass no oil on 600 rwhp turbo M/S5x running 20+ psi, along with details of how you have plumbed them. If you ask the 600+ rwhp people here, you will find next to none using recirculating catch cans. Hopefully we can learn from your experience with this sort of power on this platform.

Radium and T1 Race have extreme performance air/oil separator units likely better to be used than simple Chinese units with limited separation abilities if you have a loose motor setup.

Most people run ATM. PCV setups, because it's simple and cheap and as you seem to have found out when not using the right parts doesn't give you enough oil separation capability for a motor that spits out more oil than normal. So that is not a measurement I would use.

FWIW, I'm not that much of a fan of the Provent units - if mounted in a location that doesn't heat the can enough far too much water is absorbed into the (replaceable) fiber filter and does slow down flow by a lot in my experience.

[jakermac]

My NA catch can setup did not use intake manifold vacuum and worked perfectly. I had 2 crankcase vent outlets on the top of the valve cover - deleted the OEM outlet, and my catch can return/vacuum source went to the intake tube between the MAF and the TB. It performed exactly as it should, allowing crankcase venting and keeping oil out of the intake system. I intend to preserve this design with my boosted setup, with the exception of placing the return/vacuum source somewhere before the inlet to the turbo with a slash cut tube.

[pbonsalb]

But modded N/A does not add nearly as much crankcase pressure as triple stock power. You might be at 50% over stock. Some of us are more than 300% over stock. Having 2 outlets on top of the valve cover is helpful. A few turbo people have done that and I have thought about it. The factory hole on the side of the cover is big but the internal passageway under the cover is small. Chikinhed opened his up a bit but it can’t be opened up to anywhere near the tube diameter you see on the outside of the cover.

Yes, built engines are looser. Ring gaps are looser on highly boosted motors. Cracking a ringland is a risk otherwise. I am not an engine builder but have broken some engines and learned a little bit as a result. This has also been discussed in this forum.

Even Radium suggests the option of venting the catch can to atmosphere rather than recirculating it.

http://www.radiumauto.com/Blog/Post/Catch-Cans-101-102

Why, if it’s absolutely unnecessary? It’s not like it is hard to recirculate if that is best.

[Robocop]

i was going to say why not buy a belt driven vac pump and just put it where the A/C P/S was
but got daym they're at least $700 for bare the pump alone.

think if some cool guy made a bracket/pulley complete kit using a moroso pump ppl would buy them?

[NOTORIOUS VR]

But modded N/A does not add nearly as much crankcase pressure as triple stock power. You might be at 50% over stock. Some of us are more than 300% over stock. Having 2 outlets on top of the valve cover is helpful. A few turbo people have done that and I have thought about it. The factory hole on the side of the cover is big but the internal passageway under the cover is small. Chikinhed opened his up a bit but it can’t be opened up to anywhere near the tube diameter you see on the outside of the cover.

While I haven't done so, has anyone else actually measured their CC pressure? Also on a side note, increasing flow of your CC actually helps prevent oil splatter leaving the exit point as you will have less velocity in a larger outlet(s). You might want to look into that if you're seeing oil make its way past your current catch can setup. Again as you mentioned, these motors built for NA require far less breathing capabilities than a boosted motor (even with tighter OEM turbo tolerances).

Yes, built engines are looser. Ring gaps are looser on highly boosted motors. Cracking a ringland is a risk otherwise. I am not an engine builder but have broken some engines and learned a little bit as a result. This has also been discussed in this forum.

I'm not an engine builder either, but far too many people like build engines too loosely it seems for moderate goals on their mainly street driven car. I think most of that comes from engine builders who don't want to deal with customers that might point the finger back at them and also people who want to build motors choosing full out race motor parts for their builds where it's absolutely not required.

Even Radium suggests the option of venting the catch can to atmosphere rather than recirculating it.

http://www.radiumauto.com/Blog/Post/Catch-Cans-101-102

Why, if it’s absolutely unnecessary? It’s not like it is hard to recirculate if that is best.

I don't see them suggesting anything of the sort. Any reference to atm. venting is for very loose, high power, racing/competition engines - and while many might think they have that they don't. And if they do have a 600-800hp loosely built "race" engine in their street car then obviously doing a return style PCV system just isn't for them. I also find it funny that they (and others) try to say that returning the collected oil/condensation is bad for the engine - yet this is how all OEM systems are made (oil return) and modern oils kept at the right temps have zero issue burning off the condensation that is introduced into it.

But this thread is about the point is that you can absolutely make a very successful return PCV system that functions properly without the need to have stink in your cabin that you get with a vented system. Of course that requires some efficient planning, and the right parts to do it and a motor that is properly built that isn't spitting out oil from the outlet of the crankcase ports.

[Z-Thrizzle]

i was going to say why not buy a belt driven vac pump and just put it where the A/C P/S was
but got daym they're at least $700 for bare the pump alone.

think if some cool guy made a bracket/pulley complete kit using a moroso pump ppl would buy them?

Most of these companies offer universal mounts and spacers for their belt driven vac pump. So fabrication work shouldn't be needed.

http://www.starvacuumpumps.com/catalog/pumps

https://www.gzmotorsports.com/vacuum-pumps.html

https://www.moroso.com/moroso-shop-browse/14000/1401/

[pbonsalb]

The question is where to put the belt driven vacuum pump on a full accessory car. Delete AC and you have a space. If I delete AC, I won’t want to drive my car as much during hot weather. A very few have done this. One person mounted a mini extension pulley on an existing pulley for a dedicated mini drive for a small pump. You might be able to find the details with some searching. The vacuum pump is definitely the ultimate solution, though I still would not plumb the crankcase vapor back into the intake manifold where it will still eventually leave a coating of oil even if using a very good catch can.

As for blowby on built motors, it is possible all of us have crappy motors built by people who have no clue and overbored and made ring gaps too loose. But that is more likely to be the exception than the rule. But we are the guys making 600, 700, 800, 900 or even 1000 rwhp, so presumably we know what we are doing. Find some of us successfully doing what you propose. Or find an 800 rwhp Supra or 800 rwhp GTR or other highly modded big power small displacement turbo motor with recirculating engine vacuum assisted crankcase vent system.

[NOTORIOUS VR]

As for blowby on built motors, it is possible all of us have crappy motors built by people who have no clue and overbored and made ring gaps too loose. But that is more likely to be the exception than the rule. But we are the guys making 600, 700, 800, 900 or even 1000 rwhp, so presumably we know what we are doing. Find some of us successfully doing what you propose. Or find an 800 rwhp Supra or 800 rwhp GTR or other highly modded big power small displacement turbo motor with recirculating engine vacuum assisted crankcase vent system.

Of course that's not at all what I said, so if you're going to continue down this path I really don't care what you do or think. Actually further more you've already made up your mind that it cannot be done - so really the info I posted is better used by someone else than yourself anyway.

[Robocop]

another question.

if you leave the vent naked, no hose or anything just pointed to the hood open.

do you see some spray on the hood or anywhere after some runs?
just trying to see what is "normal".
That's how i have mine and it's just vapor coming out only time i saw oil splatter out is when the ring lands broke.

[pbonsalb]

Of course that's not at all what I said, so if you're going to continue down this path I really don't care what you do or think. Actually further more you've already made up your mind that it cannot be done - so really the info I posted is better used by someone else than yourself anyway.

Look, you have just provided theory that it should work if a recirculating catch can is done right or that built motors must be poorly built if the system is passing oil. Give us some real world examples of recirculating catch cans keeping all intake and boost passages oil free on 600+ rwhp built motor E36s, or at least similarly modded other cars if you can’t find any E36. I ask because my E36 has been forced induction for 15 years and I have been following everything posted here as well as reading widely elsewhere. The subject arises periodically.

[NOTORIOUS VR]

Look, you have just provided theory that it should work if a recirculating catch can is done right or that built motors must be poorly built if the system is passing oil. Give us some real world examples of recirculating catch cans keeping all intake and boost passages oil free on 600+ rwhp built motor E36s, or at least similarly modded other cars if you can’t find any E36. I ask because my E36 has been forced induction for 15 years and I have been following everything posted here as well as reading widely elsewhere. The subject arises periodically.

This isn't theory.

Like I said you already have your mind set that it cannot be done - in every one of your posts you've made that clear.

There is absolutely nothing special about your boosted E36 or any other boosted engine when it comes to CCV that would prevent it to be recirculated. I've already said how it can be done and why it works. If you're actually interested in doing it you would be wise to look into it - otherwise carry on with whatever you have right now (vented) which obviously doesn't work for you either since you're seeing oil PAST your catch can.

[Hova]

Zero. Chance.

But hey, if pbonsalb and I are wrong and it is possible, the N54 crowd would pay top $$$$ for a solution.

[pbonsalb]

This isn't theory.

Like I said you already have your mind set that it cannot be done - in every one of your posts you've made that clear.

There is absolutely nothing special about your boosted E36 or any other boosted engine when it comes to CCV that would prevent it to be recirculated. I've already said how it can be done and why it works. If you're actually interested in doing it you would be wise to look into it - otherwise carry on with whatever you have right now (vented) which obviously doesn't work for you either since you're seeing oil PAST your catch can.

If you ever come across examples putting the theory into practice successfully on high powered built motor cars, post them. I know I would be interested and there are probably others.

My catch can with breather seems to be doing its job, though I do sometimes smell some oil vapor and if I am on a dyno, I will see oil vapor coming out in greater amounts. Obviously, I can’t see under the hood while driving, but I do notice oily residue. Its not perfect, but I prefer this to having my intake manifold oily on the inside or oil in my turbo or intake piping. I actually ran an exhaust scavenge for a while that seemed to be successful at 600 rwhp, but I figured the oil vapor was lining the inside of my exhaust and was not sure that helped. Kept the smell away, though.

[Kenny1958]

I could do with some help getting this catch can working without oiling up my maf tube.
The blow by leaves the crank case via the separator then goes to the can. I did have it connected to my inlet but it sucks too much oily vapour, that coats my maf.
Should I run a exhaust scavenge from the outlet of my can to somewhere in the exhaust system ? if I should where is the best place to put it, if not what can I do to provide vacuum to the can.

Sent from my SM-G930F using Tapatalk

[pbonsalb]

I like that positive displacement supercharged BMW V8? Is it a stock block? Is it a kit or full custom? Who did the custom water to air intercoolers.

[Kenny1958]

Its an M112 from a jag xkr on a m62tub44 I bought the manifold adapters from toolman on here.

[jakermac]

What does the inside of the catch can look like? I KNOW the inside of my catch can has 5 layers of aluminum window screen as well as some ball/pull chain that the oily vapor is FORCED through before exiting the can. The can is very effective at trapping both moisture AND oil. In the cooler more damp PMW winter months the can collects 800ml of oily water per month that I can easily pour off. I don’t have a long enough commute to boil that water off on a regular basis. If it can trap that amount of water, I’m confident that it’ll be effective at trapping the oil too.