Vented VS. Sealed Catch Can?????

[BowDownRacing]

Why is a vented can not optimal for "these" vehicles, when every company in the market offers them as vented? I personally have installed numerous catch can setups on alot of cars, granted I never have on a dsm so my question is what makes these different from any other boosted application? I read what some are saying so I would like to know why and if its been proven, have any cars been on the dyno and tried both style catch cans, has anyone ever made a full pass with a sealed can then another pass with a vented can to prove their theory to prove which one works better than the other and why??

 

[V12 Killa]

Read: http://www.dsmtuners.com/forums/articles-engine-fuel/366890-4g63t-pcv-system.html

In short: Catch cans help with excessive crankcase pressures (ex. blowing out dipsticks & etc.) and "removes" the nasty oil/crap your engine produces.

As for Vented CCs, they just leave a light coat of oil all over engine bay.

I recommend a sealed cc (Calan's Catch Can to be exact).

 

[dsmgst1996]

I personally us a "sealed" catch can style ... i use a fuel filter Purolater F23170 in line and change it as need it take about 3 seconds and have had good results.

 

[mnim15]

I would also like to see some discussion regarding this. When talking about this with others, it seems like there is more concern with what pollutants could be recirculated back in to the combustion chamber and increase, as slight as it may be, the chance of detonation. If you had a decent properly baffled catch can that was vented to atmosphere along with lines large enough to allow crankcase pressure changes, would the only benefit to a sealed system be pollution control compliance? Would using an exhaust scavenging system provide enough vacuum or allow enough pressure change to not cause excessive crankcase pressure providing an alternative lower "risk" sealed system scenario? Also, just speculating, when there is vacuum being pulled from under the valve cover using the sealed system, does the air travel from the crankcase to the head using the oil galleys? Could this affect the oil returning to the pan? Would running lines somewhere on the short block provide better placement?

 

[tlcoolj]

Sealed catch cans should be hooked up to a vacuum to draw crankcase gases from the engine. If you have a vented one this does not happen. But lets be clear, when you have positive crankcase pressure it should ideally escape even if it is vented. The problem is all motors have some sort of blow by, where some of the combustion gases go past the rings. These gases are not removed as effeciently if you have a vented can vs. sealed, causing the oil break down and become "dirty" faster. So you must change the oil more often if you have a vented can.

For a daily driven car I would recommend a sealed can. Having a vacuum hooked up to the motor should not effect the oil returning to the pan, the motor comes like that from the factory.

 

[mnim15]

Has anyone tested the sealed system using exhaust scavenging?

 

[Michael@FP]

If you're not pulling a vacuum on your catch can you are doing it wrong.

The stock PCV system other than the size of the lines is by far the best way to setup a crankcase ventilation system. If your motor is tight and you have very little crankcase issue more than likely a catch can does nothing for you other than removing the oil from the intake system.

If you have a some crankcase issue enough to where you see some light smoke on decel you're producing more than the stock PCV system can handle and it's pushing enough oil into the intake to make it smoke. Putting a catch can that doesn't pull a vacuum and is vented will make the smoke go away but won't really alleviate your crankcase pressure. It just gives the oil some place to go while the pressure persists, all you've effectively done is increase your crankcase pressure.

Now if you're on a freshly built motor, a motor with loose tolerances, or just a worn out motor you might have excessive crankcase pressure. This can cause all sorts of fun issues, smoking at idle/cruise, smoking under load, smoking on decel, and even pressurizing the bearing housing of the turbocharger and forcing oil out of it. In this instance to truly alleviate your crankcase issue you need to IMPROVE the stock system which means it needs to retain at least the vacuum under load. So the best way to do this is to increase the size of the lines and either run them directly to vacuum sources or run them to a baffled catch can and then run the vacuum sources directly off that.

We have done the testing and so had Garrett and Holset as little as .1PSI in a bearing housing can cause leakage. Let that sink in a for a minute just that little bit of pressure can cause this to happen. A catch can vented to atmosphere with stock sized lines is useless and if you measured pressure in your crankcase vs. the stock system you would see a rise in pressure with removing the vacuum and adding a catch can alone. So if you want to do it properly and get the best of both words, run a baffled catch can with it pulling a vacuum, no oily mess in your intake or engine bay and you still get the benefit of having your crankcase scavenged of excessive pressure.

-Michael

 

[4g63t]

Read: http://www.dsmtuners.com/forums/articles-engine-fuel/366890-4g63t-pcv-system.html

In short: Catch cans help with excessive crankcase pressures (ex. blowing out dipsticks & etc.) and "removes" the nasty oil/crap your engine produces.

As for Vented CCs, they just leave a light coat of oil all over engine bay.

I recommend a sealed cc (Calan's Catch Can to be exact).

I believe all of calons cans are ether vented or to be hooked up pre filter to be under a vacuum when in boost. I don’t think he has a sealed CC...

 

[T is for TURBO]

Why is a vented can not optimal for "these" vehicles, when every company in the market offers them as vented? I personally have installed numerous catch can setups on alot of cars, granted I never have on a dsm so my question is what makes these different from any other boosted application? I read what some are saying so I would like to know why and if its been proven, have any cars been on the dyno and tried both style catch cans, has anyone ever made a full pass with a sealed can then another pass with a vented can to prove their theory to prove which one works better than the other and why??

This subject has been beaten to death. Read the link above and it explains it VERY clearly.

Cliff notes. Sealed units are FAR more effective at pulling crank case pressure out because there is a vacuum effect pulling it out, vs just blowing it out. Yes there are applications that require it to be vented. However, in most cases a sealed unit is best option.

Also, catch cans really aren't a performance piece, that is why no one dynos their car before and after installing one. If it evacuates all the crankcase pressure, it is doing it's job, whether it's vented or not.

I believe all of calons cans are ether vented or to be hooked up pre TURBO to be under a vacuum when in boost. I don't think he has a sealed CC...

Fixed for you.

A pre-turbo routed can is a sealed unit. A vented can is one with on little filter on top.

Has anyone tested the sealed system using exhaust scavenging?

I believe a few people have, and it has been determined, especially with our large diameter exhaust pipes, the vacuum is not substantial enough to effectively pull enough crank case pressure out of the system. It might work with a smaller diameter pipe that has higher exhaust velocities, but then you would have an under performing exhaust...

 

[4g63t]

This subject has been beaten to death. Read the link above and it explains it VERY clearly.

Cliff notes. Sealed units are FAR more effective at pulling crank case pressure out because there is a vacuum effect pulling it out, vs just blowing it out. Yes there are applications that require it to be vented. However, in most cases a sealed unit is best option.

Also, catch cans really aren't a performance piece, that is why no one dynos their car before and after installing one. If it evaluates all the crankcase pressure, it is doing it's job, whether it's vented or not.



Fixed for you.

A pre-turbo routed can is a sealed unit. A vented can is one with on little filter on top.

Thanks that’s what I meant haha. When I read sealed, I picture a totally sealed cheepo can.

 

[ErikTande]

How important is a filter in the sealed catch can? Can you use use a fuel filter inline like dsmgst1996 suggested? Or should I just use stainless steel scrubber?

 

[BowDownRacing]

This subject has been beaten to death. Read the link above and it explains it VERY clearly.

Cliff notes. Sealed units are FAR more effective at pulling crank case pressure out because there is a vacuum effect pulling it out, vs just blowing it out. Yes there are applications that require it to be vented. However, in most cases a sealed unit is best option.

Also, catch cans really aren't a performance piece, that is why no one dynos their car before and after installing one. If it evacuates all the crankcase pressure, it is doing it's job, whether it's vented or not.

I see your response and seen that you say it doesnt matter on the dyno. I have worked at a dyno for 7 years I know we dyno test everything, injectors, cams, intakes, exhausts, headers, and yes we have tested catch can setups. I have yet to test one on a DSM and thats the reasoning behind my question so NO it wasnt covered in the link you mentioned. I wanted to know why and if it was proven. It has yet to be proven. I had 4 imports I built making between 539-798 hp to the wheels. I tried multiple catch can setups. I tried running one large setup 3 small setups yet they were all vented. I am not trying to make a thread to just clutter the site. I want to make a thread that helps other figure out what I am wondering myself. If you say a catch can isnt a performance piece then why can it make so much of a difference on a vehicle? It is a performance piece, it helps your motor breath it helps free up horsepower. Your statement is false sorry to say.

If you're not pulling a vacuum on your catch can you are doing it wrong.

The stock PCV system other than the size of the lines is by far the best way to setup a crankcase ventilation system. If your motor is tight and you have very little crankcase issue more than likely a catch can does nothing for you other than removing the oil from the intake system.

If you have a some crankcase issue enough to where you see some light smoke on decel you're producing more than the stock PCV system can handle and it's pushing enough oil into the intake to make it smoke. Putting a catch can that doesn't pull a vacuum and is vented will make the smoke go away but won't really alleviate your crankcase pressure. It just gives the oil some place to go while the pressure persists, all you've effectively done is increase your crankcase pressure.

Now if you're on a freshly built motor, a motor with loose tolerances, or just a worn out motor you might have excessive crankcase pressure. This can cause all sorts of fun issues, smoking at idle/cruise, smoking under load, smoking on decel, and even pressurizing the bearing housing of the turbocharger and forcing oil out of it. In this instance to truly alleviate your crankcase issue you need to IMPROVE the stock system which means it needs to retain at least the vacuum under load. So the best way to do this is to increase the size of the lines and either run them directly to vacuum sources or run them to a baffled catch can and then run the vacuum sources directly off that.

We have done the testing and so had Garrett and Holset as little as .1PSI in a bearing housing can cause leakage. Let that sink in a for a minute just that little bit of pressure can cause this to happen. A catch can vented to atmosphere with stock sized lines is useless and if you measured pressure in your crankcase vs. the stock system you would see a rise in pressure with removing the vacuum and adding a catch can alone. So if you want to do it properly and get the best of both words, run a baffled catch can with it pulling a vacuum, no oily mess in your intake or engine bay and you still get the benefit of having your crankcase scavenged of excessive pressure.

-Michael

Thank you, this helped me get a little better understanding.

 

[1qkfwd]

Best can setup is measuring your crankcase pressure and getting it down to zero or into a vacuum state. Pretty much goes for any car out there.

 

[T is for TURBO]

I have yet to test one on a DSM and thats the reasoning behind my question so NO it wasnt covered in the link you mentioned.

You asked:

Why is a vented can not optimal for "these" vehicles, when every company in the market offers them as vented?

Pretty sure it was answered, in the link.

Important point #5: Catch cans should always be connected to a vacuum source to help pull air through them, rather than vented to atmospheric pressure.

If you have zero crank case pressure, the ventilation system is doing it's job, and there is no need to dyno the car. And if you want to consider it a performance part, go for it. I personally do not.

 

[dsm-dad]

Read: http://www.dsmtuners.com/forums/articles-engine-fuel/366890-4g63t-pcv-system.html

In short: Catch cans help with excessive crankcase pressures (ex. blowing out dipsticks & etc.) and "removes" the nasty oil/crap your engine produces.

As for Vented CCs, they just leave a light coat of oil all over engine bay.

I recommend a sealed cc (Calan's Catch Can to be exact).

So with the maximum relief diagram in this article or either other, my question is what if your running speed density and have done away with the intake snorkel. Where is the best place to draw vacuum from?

should it be ran off of a filter from turbo or possibly the turbo itself?

 

[Lou98GSX]

I have mine vented cause i was always afraid to get oil in my intercooler and i don't want to take a chance and go with a closed system . Has anybody ever pulled one of there intercooler pips to check if there is any oil getting by there closed catch can systems .

 

[miliman13]

So with the maximum relief diagram in this article or either other, my question is what if your running speed density and have done away with the intake snorkel. Where is the best place to draw vacuum from?

should it be ran off of a filter from turbo or possibly the turbo itself?

If your absent of a source pre-turbo. You can instead connect it to the intake manifold.
The fast velocity of traveling air in the intake will reduce the pressure in the "can" so it will work the same as having it pre turbo.
According to * Bernoulli's principal * pressure and velocity are directly
in-proportional .

 

[greengoblin]

If your absent of a source pre-turbo. You can instead connect it to the intake manifold.
The fast velocity of traveling air in the intake will reduce the pressure in the "can" so it will work the same as having it pre turbo.
According to * Bernoulli's principal * pressure and velocity are directly
in-proportional .

The intake manifold will be pressurized under boost. That would make the problem worse.
That is why the OEM unit has two vent sources. One for decel and idle, the PCV valve that connects to the intake manifold. The PCV valve shuts it off under boost and the other one pre turbo takes over.

 

[dsm-dad]

The intake manifold will be pressurized under boost. That would make the problem worse.
That is why the OEM unit has two vent sources. One for decel and idle, the PCV valve that connects to the intake manifold. The PCV valve shuts it off under boost and the other one pre turbo takes over.

Thank you

 

[miliman13]

The intake manifold will be pressurized under boost. That would make the problem worse.
That is why the OEM unit has two vent sources. One for decel and idle, the PCV valve that connects to the intake manifold.
The PCV valve shuts it off under boost and the other one pre turbo takes over.

Won't the check valve prevent that?( Under boost)

Assuming there is a check valve.

So it would still work at idle cruise
( not boost).

I was under the assumption there would be a check valve inplace since the OP mentioned the * max relieve * diagram.

 

[greengoblin]

Won't the check valve prevent that?( Under boost)

Assuming there is a check valve.

So it would still work at idle cruise
( not boost).

I was under the assumption there would be a check valve in place since the OP mentioned the * max relieve * diagram.

Yes, it would work on idle and when the car is under vacuum at cruise but as the factory recognized that is not a solution since it works maybe half the time.
When engine is under boost is when problems really start and why * max relieve * is required and being discussed. Hooking it up with a check valve to the intake manifold only would keep any venting from happening under boost and create pressure in the crankcase due to blow by having nowhere else to go.

What you said in your first post did not mention a check valve and that would turn the the crankcase into a balloon. I just do not want anyone to turn their cars in to dip stick puking monsters.

 

[dsm-dad]

Ok so I'm not sure what is the best option now 3 lines or 4, going to be running speed density, so i should pull vacuum from my jmfab intake with check vavle?