Breathers & Catch Cans Affect of Vacuum, Oil Pressure and Oil Flow in FI Applications

[07TGGT]

The reason I am starting this thread is to gather some information on how breathers and catch cans affect vacuum.

I have been trying to research what amount of vacuum and the amount of pressure is needed for the engine to function properly, especially with the TiVCT since it relies on a specific pressure to operate, but haven't been able to find anything specific for the 5.0.

I am probably overthinking it but I would like to know before I buy the components to build my own breather system or remote catch can system. I don't know how much more, if any, a FI application is affected than a NA application.

If you look in this thread, http://http://www.s197forum.com/forum/showthread.php?p=1858371#post1858371, you will see what two options I am trying to decide between. I will be running the Paxton on 5-9lbs.

So, on to my questions...

-What is the amount of vacuum needed for the 5.0L to function properly, along with the other systems?

-What oil pressures should be seen at cold temperatures(enviroment) upon start-up, idle, and cruising?

-What oil pressures should be seen at hot temperatures(enviroment) upon start-up, idle, and cruising?

-What oil temperatures are ideal, both cold(start-up) and hot(operating temperature)?

-Which will cause less of a loss of vacuum, breather can or catch can?

-Does the diameter of the hose going to the breather can/catch can affect the vacuum?

-Does the diameter of the hose going to the breather can/catch can affect the pressure?

-Does the diameter of the hose going to the breather can/catch can affect the flow going in and out?

-If the catch can has two seperate hose sizes such as AN-8 and AN-12, how adversly will that affect the system?

I think I covered everything I wanted to know! LOL

 

[Bullitt 3309]

I am installing this one in mine, I believe he has a setup for the GT500 which should cover your boosted application. I enjoyed the test vs JLT.

http://www.svtperformance.com/forum...0-bobs-auto-sports-oil-separator-install.html

 

[07TGGT]

I am installing this one in mine, I believe he has a setup for the GT500 which should cover your boosted application. I enjoyed the test vs JLT.

http://www.svtperformance.com/forum...0-bobs-auto-sports-oil-separator-install.html

The Bob's is a very nice piece but I've already decided that I want to eliminate the PCV system completely, which I will do by going with the Boss 302R breather setup.

 

[TW1NTRB0]

The Bob's is a very nice piece but I've already decided that I want to eliminate the PCV system completely, which I will do by going with the Boss 302R breather setup.

FYI, later today if I get around to taking pictures I will be posting my Boss 302R breather system for sale in the classifieds if you're interested.

 

[07TGGT]

FYI, later today if I get around to taking pictures I will be posting my Boss 302R breather system for sale in the classifieds if you're interested.

Definitely interested. I'll be looking out for it.

 

[Sky Render]

The Bob's is a very nice piece but I've already decided that I want to eliminate the PCV system completely, which I will do by going with the Boss 302R breather setup.

Can I ask why you're going to completely eliminate it? You can't apply any vacuum to the crankcase if you're only running breathers.

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[07TGGT]

Well, I don't want any oil, wether it be vapors or liquid form, going through the intake. From what I have read most catch cans don't do that well with boosted applications as far as filtering out the oil. Also, this setup just looks so damn clean.

Can you explain more about not being able to supply vacuum to the crankcase? I'm only asking because I don't know. Google doesn't yeild that great of technical information on subjects such as this.

 

[Sky Render]

Well, I don't want any oil, wether it be vapors or liquid form, going through the intake. From what I have read most catch cans don't do that well with boosted applications as far as filtering out the oil. Also, this setup just looks so damn clean.

Can you explain more about not being able to supply vacuum to the crankcase? I'm only asking because I don't know. Google doesn't yeild that great of technical information on subjects such as this.

OK, so let's talk about the factory system to use as an example. you've got 2 lines coming from the valve covers. One goes to the airbox and one goes through a PCV valve (one-way check valve) to the intake manifold. Each of those lines pulls a vacuum on the crankcase. The airbox always has a vacuum, even on a boosted application, because it is sucking in air. The check valve closes under WOT, and has manifold vacuum on it all other times.

If you go to only a breather setup, you are venting directly to atmosphere, which has zero vacuum. So the crankcase is no longer being actively vented.

A little oil vapor in the intake stream is not going to cause engine damage, and a GOOD catch can will filter out most of it.

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[Sky Render]

Sorry I'm on TDY and on a phone and it's hard to type a lot. Try loooking at this article. It's about N/A motors, but it's got some good info:

http://www.motoiq.com/MagazineArticles/ID/2032/Crankcase-Ventilation-Explained--NA-Edition.aspx

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[07TGGT]

OK, so let's talk about the factory system to use as an example. you've got 2 lines coming from the valve covers. One goes to the airbox and one goes through a PCV valve (one-way check valve) to the intake manifold. Each of those lines pulls a vacuum on the crankcase. The airbox always has a vacuum, even on a boosted application, because it is sucking in air. The check valve closes under WOT, and has manifold vacuum on it all other times.

If you go to only a breather setup, you are venting directly to atmosphere, which has zero vacuum. So the crankcase is no longer being actively vented.

A little oil vapor in the intake stream is not going to cause engine damage, and a GOOD catch can will filter out most of it.

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I understand how the PCV system in our veichles are setup and how they work. Thanks for the link, it expanded more onto what I've already read.

Higher intake manifold pressures increase blow-by, which in turn introduces more oil into the intake and intake manifold. Under idle and partial throttle the PCV is active, but under WOT it is not. So all the air that contains more oil due to blow-by is being routed through the intake, especially with boosted applications due to higher than atmospheric pressure within the intake manifold. That can lead to several issues if the engine components are not serviced and cleaned regularly.

As you already know, oil dilutes the fuels octane which can lead to detonation and hot spots on the pistons. So, the engine simply performs better with zero oil mixed into the air/fuel mixture.

According to Peterson and other sources, the Peterson Breather Can PN 08-0400 reduces crankcase pressure and loss of vacuum, and most of all, stop inducing oil-contaminated air into the engine.

Hell, Ford wouldn't run this setup on the Boss 302R/S or Cobra Jet if it didn't work. Is it good for the enviroment? Absolutely not, but I would drive a Prius if I cared that much LOL.

http://bossmustangsonline.com/index.php?topic=4357.40

http://www.stangtv.com/tech-stories/engine/review-petersons-externally-vented-air-oil-separator/

So when you say it has zero vacuum I find that hard to believe, although you are partially correct. Under WOT the intake manifold pressure is the same as the atmospheric pressure, which means no vacuum, but that remains the same no matter if the PCV system is stock, has been modified, or removed completely.

Under idle and partial throttle there will be vacuum, and even more so with a turbo or supercharger.

I don't have the schematics on the Peterson Breather Can PN 08-0400 but I assume it vents once a specific pressure is reached, allowing it to reduce loss of vacuum when idling and under partial throttle.

I believe you when you say a little amount will not hurt a engine BUT I say no oil is better than a little oil no matter how little the amount. I'm OCD and I like to have shit done perfectly.

Okay, now my head hurts LOL.

 

[Falkinman]

Are you planning on plugging the vacuum lines? If you do that you will cause pressure to build up in the crank case which will cause oil seals to start to leak and blow out. You NEED vacuum in your crank case. If you don't evacuate your crank case you will have oil mist which will act like friction to the spinning crankshaft and cause you to lose horsepower. Te stock setup described in a previous post works with the PVC causing a vacuum on the crank case in all but full throttle situations. At full throttle the hose going to the air box pulls a vacuum and the PCV valve closes. Additionally crank case vacuum helps quite a bit with piston ring seal. If you don't have good ring seal you will start getting blow by past the rings and then crank case pressure will really start to climb increasing oil leakage from seals and more loss in horsepower. Ford knew what they were doing when they designed it. I wouldn't mess with it if I were you. Just install an oil catch can.

 

[zeroescape]

I would have thought that the PCV lines from intake manifold or CIA act as a venturi system. Basically it wouldnt matter what the pressure is along the intake system as long as you have enough velocity.

 

[07TGGT]

Are you planning on plugging the vacuum lines? If you do that you will cause pressure to build up in the crank case which will cause oil seals to start to leak and blow out. You NEED vacuum in your crank case. If you don't evacuate your crank case you will have oil mist which will act like friction to the spinning crankshaft and cause you to lose horsepower. Te stock setup described in a previous post works with the PVC causing a vacuum on the crank case in all but full throttle situations. At full throttle the hose going to the air box pulls a vacuum and the PCV valve closes. Additionally crank case vacuum helps quite a bit with piston ring seal. If you don't have good ring seal you will start getting blow by past the rings and then crank case pressure will really start to climb increasing oil leakage from seals and more loss in horsepower. Ford knew what they were doing when they designed it. I wouldn't mess with it if I were you. Just install an oil catch can.

Did you actually read any of the links I posted?
Are you fimiliar with the Boss 302R/S Peterson BREATHER CAN setup operates?
I don't think you can answer yes to either of those otherwise you wouldn't have made a ignorant comment.

I now have a pretty good understanding thanks to some helpful members here, and through means of my own research.

You do realize even when running the factory PCV system there is still blow-by correct? It's amplified even more in a FI application due to higher than atmospheric pressures in the intake manifold.

Ford wouldn't put it on the Cobra Jet and Boss 302R/S if it didn't work and have a huge benifit over the factory PCV system, especially under conditions such as those that those cars go through.

The Bos 302R/S Peterson BREATHER CAN setup benifits are as follows:
-Eliminates the PCV system.
-Stops the induction of oil contaiminated air/fuel mixture into engine.
-Protects again vacuum loss.
-Lowers crankcase pressure.
-Eliminates gunk build up on the TB, and in the intake manifold.
-Cleans up the engine bay.

 

[07TGGT]

I would have thought that the PCV lines from intake manifold or CIA act as a venturi system. Basically it wouldnt matter what the pressure is along the intake system as long as you have enough velocity.

No, it's hard for me to interupt since I am just learning about the PCV system but read this link. It talks about Venturi Effect and Venturi vacuum.
http://en.wikipedia.org/wiki/Manifold_vacuum

 

[07TGGT]

Would still like some input on my original questions.

 

[Sky Render]

Hell, Ford wouldn't run this setup on the Boss 302R/S or Cobra Jet if it didn't work. Is it good for the enviroment? Absolutely not, but I would drive a Prius if I cared that much LOL.

http://bossmustangsonline.com/index.php?topic=4357.40

http://www.stangtv.com/tech-stories/engine/review-petersons-externally-vented-air-oil-separator/

Yeah, but the 302S is N/A. Things change a bit when you're pressurizing the crankcase via blowby caused by forced induction.

So when you say it has zero vacuum I find that hard to believe, although you are partially correct. Under WOT the intake manifold pressure is the same as the atmospheric pressure, which means no vacuum, but that remains the same no matter if the PCV system is stock, has been modified, or removed completely.

Under idle and partial throttle there will be vacuum, and even more so with a turbo or supercharger.

I don't have the schematics on the Peterson Breather Can PN 08-0400 but I assume it vents once a specific pressure is reached, allowing it to reduce loss of vacuum when idling and under partial throttle.

I believe you when you say a little amount will not hurt a engine BUT I say no oil is better than a little oil no matter how little the amount. I'm OCD and I like to have shit done perfectly.

Okay, now my head hurts LOL.

There is no vacuum if it is only vented to atmosphere, because atmosphere has no vacuum. In order to get a vacuum in the system, you would have to plumb the crankcase to the airbox in front of the supercharger/turbocharger. The sucking created by the compressor would then produce a vacuum on the crankcase.

Anywho, there are plenty of guys out there running metric shit-tons of boost with just breather cans vented to ambient atmosphere, so I'm sure you'll be fine. I've always been under the impression that a bit of vacuum is good for piston ring longevity, so I prefer to route at least one bank of cylinders to the airbox through a sealed catch can to provide vacuum.

Thanks for the links to those breather cans, BTW. They are nice, and I might be picking one up.

 

[07TGGT]

Yeah, but the 302S is N/A. Things change a bit when you're pressurizing the crankcase via blowby caused by forced induction.



There is no vacuum if it is only vented to atmosphere, because atmosphere has no vacuum. In order to get a vacuum in the system, you would have to plumb the crankcase to the airbox in front of the supercharger/turbocharger. The sucking created by the compressor would then produce a vacuum on the crankcase.

Anywho, there are plenty of guys out there running metric shit-tons of boost with just breather cans vented to ambient atmosphere, so I'm sure you'll be fine. I've always been under the impression that a bit of vacuum is good for piston ring longevity, so I prefer to route at least one bank of cylinders to the airbox through a sealed catch can to provide vacuum.

Thanks for the links to those breather cans, BTW. They are nice, and I might be picking one up.

If there was no vacuum how would the brake booster function? I just don't see how this setup eliminates all the vacuum. Guess I need it broken down Barney style for me LOL.

I'll have to research more into it I suppose.

No problem, they're really nice pieces.

 

[HEMI LOL]

im very happy with my Moroso catch can setup. its a quality piece.

 

[Sky Render]

If there was no vacuum how would the brake booster function? I just don't see how this setup eliminates all the vacuum. Guess I need it broken down Barney style for me LOL.

I'll have to research more into it I suppose.

No problem, they're really nice pieces.

There is still vacuum in the intake manifold when you're not under boost, and that is what the brake booster is connected to. But that vacuum is not being applied to the crankcase in the setup you are talking about, because there is no vacuum line going from the intake manifold to the crankcase. (In a "normal" setup, there would be a vacuum line running from the intake manifold through a 1-way check valve to the crank case, which provides vacuum to the crankcase while the intake manifold is under vacuum. A SECOND line would run from the crankcase to the airbox, which would provide vacuum to the crankcase while the intake manifold is under boost.)

What I'm trying to say is that the crankcase doesn't get a vacuum unless you run a line with vacuum to it.

im very happy with my Moroso catch can setup. its a quality piece.

The lines that come with the Moroso kit are known to collapse under sustained heavy vacuum. That's why the factory lines are hard plastic. The Moroso can itself is a quality piece, but it needs better lines to function properly.

 

[DSargent09]

I will be peeking in on this thread frequently. I am currently running a breather on the passenger side, and a hose to the air box on driver side. I dont think it has a check valve on the driver side.

I originally set it up how paxton suggest, but threw a CEL due to lean condition on one of the banks. I assumed I was getting a vac leak somewhere, and switched to a breather on that side and it solved my problem. So Yeah. I too am eager to learn about this portion of my car.

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