difference in oil catch cans

[gsx4357]

can any one tell me the difference of a oil catch can that has a breather on it in comparison to one that doesn't? i made a catch can today and hooked it up to my valve cover and to the intake pipe before the turbo...i was just wondering was the difference and which one is better. breather or no breather? And one more thing i was wondering if it would be a good idea to make a second on for the PCV valve to the intake manifold...good idea or doesn't really matter? thanks for any input.

 

[SOADweskey]

In my opinion the best way is to run it back into the intake like you have it as it provides vacuum under boost to help evacuate air from the crankcase.

A catch can on the pcv line wouldn't hurt anything either.

Also it is very DSMer of you to be making your own catch cans but did you build in any way of filtering particulates and oil out of the air that gets into the catch can before the air goes back to the intake?

I'm running one of these catch cans and I love the fact that it has internal baffles and a filter mesh inside to remove as much oil from the air as possible. Saikou Michi Oil Catch Tank Company Here is a link to what the inside of the can looks like. http://www.saikoumichi.com/OCC_explanation.htm

 

[1990AWD]

If you hook it back up to a vacuum source, it will actually pull the gases out of the crankcase, instead of just venting the crankcase.

 

[Calan]

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

 

[Bill Hincher]

with a catch can, pressure is pushed out of the valve cover into the top of the catch can, then oil should seperate in the catch can and the solid oil should return to the oil pan, PCV valve at the top yes and a baffle in the center but no breather

 

[Bill Hincher]

I did

 

[gsx4357]

In my opinion the best way is to run it back into the intake like you have it as it provides vacuum under boost to help evacuate air from the crankcase.

A catch can on the pcv line wouldn't hurt anything either.

Also it is very DSMer of you to be making your own catch cans but did you build in any way of filtering particulates and oil out of the air that gets into the catch can before the air goes back to the intake?

I'm running one of these catch cans and I love the fact that it has internal baffles and a filter mesh inside to remove as much oil from the air as possible. Saikou Michi Oil Catch Tank Company Here is a link to what the inside of the can looks like. Saikou Michi OCC Explanation

no i didn't put any baffles in it but now that you mention it i think i will...do you know what i can use to make it happen?

 

[SOADweskey]

I have never thought about just buying the internal material. A quick search brought me to a product like this. I can imagine that tack welding this would be difficult as it is so thin but perhaps epoxied into place inside the can or something. Corrugated, Flat Metal Mesh and Bonded Aluminum Filter Media

 

[Calan]

FWIW, I spent 3 months and $800 working with a filter media engineering company to come up with the custom filter material that I use in my cans. It ain't easy.

The problem is that 90% of the stuff you want filtered out of blow-by gases (nitrogen compounds, hydrocarbons, etc) is sub-micron sized particles and suspended aerosols. Any of the common "mesh" type filters will only remove some of the larger particles and liquids due to gravity, condensation from pressure drop/cooling, and through collisions with the mesh. But most of it goes right on through the can and into your engine...unless you have some type of coalescing material that can remove it without introducing too large of a pressure drop.

In my experience (with almost every sealed can and filter material on the market), you are either catching a lot of crap with the can but have high crankcase pressure, or you have low crankcase pressure but the can isn't doing much (other than maybe catching a lot of liquid oil...which shouldn't be coming out of the VC in the first place).

Finding that balance between highly efficient filtering and a low pressure drop...is much harder to accomplish than most people realize.

Anything is better than nothing though.


***

Definitely no disrespect intended toward Wes, but one reason I don't like the Saikou can (besides the mesh filter) is that with very little oil collected in the bottom, you begin trying to push all of your crankcase pressure through tiny relief holes. That coupled with the pressure drop across the filter material and the turbulence created at the 90* single outlet creates a less-than-ideal airflow pattern IMO.

 

[Bill Hincher]

FWIW, I spent 3 months and $800 working with a filter media engineering company to come up with the custom filter material that I use in my cans. It ain't easy.

The problem is that 90% of the stuff you want filtered out of blow-by gases (nitrogen compounds, hydrocarbons, etc) is sub-micron sized particles and suspended aerosols. Any of the common "mesh" type filters will only remove some of the larger particles and liquids due to gravity, condensation from pressure drop/cooling, and through collisions with the mesh. But most of it goes right on through the can and into your engine...unless you have some type of coalescing material that can remove it without introducing too large of a pressure drop.

In my experience (with almost every sealed can and filter material on the market), you are either catching a lot of crap with the can but have high crankcase pressure, or you have low crankcase pressure but the can isn't doing much (other than maybe catching a lot of liquid oil...which shouldn't be coming out of the VC in the first place).

Finding that balance between highly efficient filtering and a low pressure drop...is much harder to accomplish than most people realize.

Anything is better than nothing though.


***

Definitely no disrespect intended toward Wes, but one reason I don't like the Saikou can (besides the mesh filter) is that with very little oil collected in the bottom, you begin trying to push all of your crankcase pressure through tiny relief holes. That coupled with the pressure drop across the filter material and the turbulence created at the 90* single outlet creates a less-than-ideal airflow pattern IMO.

you dont filter the material with a catch can, it seperates solids from gasses, the gasses are sent into the intake manifold to be burned with the fuel and the seperated oil is returned to the crankcase, the weight of the oil will allow the seperation, the baffle wont allow crankcase pressure to blow back up the catch can

 

[Calan]

you dont filter the material with a catch can, it seperates solids from gasses, the gasses are sent into the intake manifold to be burned with the fuel and the seperated oil is returned to the crankcase

I have no idea what you are trying to say with that first part, but if you read the article as you say you did, you would know why returning the crap that gets filtered out with a good catch can back into the oil supply is a really bad idea.

the weight of the oil will allow the separation

No... it won't. Did you even read what you quoted?

The problem is that 90% of the stuff you want filtered out of blow-by gases (nitrogen compounds, hydrocarbons, etc) is sub-micron sized particles and suspended aerosols. Any of the common "mesh" type filters will only remove some of the larger particles and liquids due to gravity, condensation from pressure drop/cooling, and through collisions with the mesh. But most of it goes right on through the can and into your engine...unless you have some type of coalescing material that can remove it without introducing too large of a pressure drop.