Oil catch can or seperator...

[flaatr]

Which do you run and why?

Trying to decide which way to go.

-Raffi

 

[2GFWDbeast]

An oil catch can is used in turbo applications, or high-performance race applications where excessive blow-by (leakage past the piston rings) of air and fuel vapor occurs. This creates a positive pressure in the crankcase. Engine manufactures have placed a valve on the engine block which releases this pressure. This valve is known as a PCV (Positive Crankcase Ventilation) valve. During engine operation, blow-by gases, as well as oil mist from the rotating components of the engine, pass through the PCV valve and are routed back into the intake for the engine to burn off. However, some of the oil mist and other products settle along the engine intake and over time form a "gunk." The oil catch can collects the oil mist and condenses the fuel vapors while allowing "cleaner" gases to be passed back into the intake. Typically the blow-by gasses are passed through a wire mesh, which give the vapor droplets something to adhere to. Since the oil catch cans condense the vapor portion of the gasses, they will need to be drained periodically of all the oil, fuel and other contaminants.

The oil separator is used to lower oil pressure between the oil pan/crankcase and the oil seal. Without it there is a high probability that you will be spewing oil out the back of your engine. The 2g oil seal plate already has this part built into it, so no worries for 2g guys still with the 7-bolt.

 

[flaatr]

I follow you... so what's the main difference between catch cans that have a breather filter and those that don't?

Basically something like this...

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vs something like this...

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These are not specifically the cans I am looking at/for... they are just examples.

-Raffi

 

[2GFWDbeast]

the one with the breather is so you can use it and not have to vent it back into your intake pipe. If you used a sealed catch can and didn't have the breather on it, it would build up so much pressure that most likely your dip stick would blow out. The other is so you can draw out pressure and or oil and still filter it and vent it to your intake.

 

[flaatr]

Thanks for the input but I don't follow you...

The non-breather version is what I've seen most used... so is the breather version the right way to go? Are there any issues with boost pressure in the intake?

-Raffi

 

[Aproductions]

Don't get the filtered one like that. This causes unmetered air to come into the motor.

Get the sealed version and you can put it in your choice of 2 places.


Bewteen the intake and valve cover breather port.

Or between the PCV valve and the nipple on the intake manifold.


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


Read that first and ask questions later.

 

[Th3DooM]

Don't get the filtered one like that. This causes unmetered air to come into the motor.

You could still use the PCV valve to prevent this.

 

[flaatr]

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

Very nice...
I think this answers all my questions!

-Raffi

 

[Aproductions]

you could still use the pcv valve to prevent this.

huh?

 

[Shake_Zulla]

Don't get the filtered one like that. This causes unmetered air to come into the motor.

Get the sealed version and you can put it in your choice of 2 places.


Bewteen the intake and valve cover breather port.

Or between the PCV valve and the nipple on the intake manifold.


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


Read that first and ask questions later.

You could still use the PCV valve to prevent this.

huh?

I think maybe the Doom forgot that the 4g63 has a MAF sensor and the 420a doesn't. The first quote is correct the ECU will lean out the fuel if a vented catch can is used. Granted knowing how much preasure the VC is pulling in and its effect on the fuel map and it's consequential negative effect in combination with leaning out a turbo system is possible, however, the mathematical equations and technical data needed would far out weight buying a non vented can. In laymans terms don't vent it.

 

[2GFWDbeast]

I think maybe the Doom forgot that the 4g63 has a MAF sensor and the 420a doesn't. The first quote is correct the ECU will lean out the fuel if a vented catch can is used. Granted knowing how much preasure the VC is pulling in and its effect on the fuel map and it's consequential negative effect in combination with leaning out a turbo system is possible, however, the mathematical equations and technical data needed would far out weight buying a non vented can. In laymans terms don't vent it.

not true about about leaning out. i have mine like that the fuel trims are perfect.

 

[Shake_Zulla]

not true about about leaning out. i have mine like that the fuel trims are perfect.

Hmm interesting, looking at your mod list it looks like you have done some tunning though I wonder if you increased the fuel trims to compensate? Not trying to argue it's just everything I've read has pointed to doing this on a stock engine will lean out the fuel. Do you have anymore data to support this? I don't have a 4g63 but my friend has a wrx and a tunned ecu for higher boost and we are preparing to install a catch can we didn't want to screw up the tune and have to take it back in.

 

[Aproductions]

Yeah I was wondering that too.

I mean there isn't any vacuum lines or anything so it should work without unmetered air but I don't know.

 

[2GFWDbeast]

Hmm interesting, looking at your mod list it looks like you have done some tunning though I wonder if you increased the fuel trims to compensate? Not trying to argue it's just everything I've read has pointed to doing this on a stock engine will lean out the fuel. Do you have anymore data to support this? I don't have a 4g63 but my friend has a wrx and a tunned ecu for higher boost and we are preparing to install a catch can we didn't want to screw up the tune and have to take it back in.

It's purpose is to allow clean air in to the valve cover, where it normally exits out of the PCV valve. The "other" end of the valve cover breather hose is connected to the air intake., which provides nicely filtered air.

Unfortunately, DSM engines don't always work that way. As it turns out, there is often enough pressure in the engine to force air out of the breather hose, rather than in. This doesn't usually happen a lot, but it does happen under certain operating conditions. Thus, instead of clean air being drawn in through the breather hose, oily air can sometimes escape out. Contributing factors for this are excessive crankcase pressure, a relatively small PCV valve, and poor isolation inside the valve cover between the breather hose (the inlet) and the PCV valve (the outlet).

This also means that the engine can suck in small amounts of engine oil through the hose as well, since the other end is connected to the air intake. Over time, the oil will dirty up the inside of most of the intake piping, including the intercooler and turbo. Obviously a dirty intercooler does not work as well as a clean one, and most people don't like the idea of anything other than air getting in to the turbo.

It is important to note that the car was designed this way, and there is no real harm or damage by leaving things the way they are - however ineffective the whole system might seem. However, some people prefer to keep the trace oil out of their intake.

Point being said is "THERE IS NO UN-METERED AIR" its not a vacuum source.

 

[Aproductions]

So a vented can is fine unless you hook it up to the intake and the valve cover nipple.

But, you could hook it up to the valve cover nipple and then just vent it with no problems right?

 

[2GFWDbeast]

i have speed density on my car so in my case i has a catch can with a breather on it, since i can't vent back to the intake pipe seeing that i dont have one anymore.

 

[Aproductions]

I am on the stock 2g maf.

Which on these 3 methods would be best.

All delete the PCV valve.


1. 2 ins and vent

2. 2 ins and 1 out to the intake

3. 2 ins and 2 out to the intake

 

[Shake_Zulla]

It's purpose is to allow clean air in to the valve cover, where it normally exits out of the PCV valve. The "other" end of the valve cover breather hose is connected to the air intake., which provides nicely filtered air.

Unfortunately, DSM engines don't always work that way. As it turns out, there is often enough pressure in the engine to force air out of the breather hose, rather than in. This doesn't usually happen a lot, but it does happen under certain operating conditions. Thus, instead of clean air being drawn in through the breather hose, oily air can sometimes escape out. Contributing factors for this are excessive crankcase pressure, a relatively small PCV valve, and poor isolation inside the valve cover between the breather hose (the inlet) and the PCV valve (the outlet).

This also means that the engine can suck in small amounts of engine oil through the hose as well, since the other end is connected to the air intake. Over time, the oil will dirty up the inside of most of the intake piping, including the intercooler and turbo. Obviously a dirty intercooler does not work as well as a clean one, and most people don't like the idea of anything other than air getting in to the turbo.

It is important to note that the car was designed this way, and there is no real harm or damage by leaving things the way they are - however ineffective the whole system might seem. However, some people prefer to keep the trace oil out of their intake.

Point being said is "THERE IS NO UN-METERED AIR" its not a vacuum source.

I don't think I totally agree with that. On a stock 4g63 the air being brought into the valve cover is on the intake before the turbo but after the mass air flow sensor so if you vent your catch can from the atmosphere the maf no longer picks up the fresh air going to the vc. Now the ecu sees less air coming in through the intake and cuts the fuel to match and now you are running lean. The same ammount of air is going into the vc and intake, the can doesn't change that, however, the air that use to be metered by the maf thats going into the vc is not anymore. Now if you are running a tunning device and a wide band you can correct this because you know what you a/f ratio is and the ecu is no longer using just the MAF. If you where not constantly monitering this and just tuned it once as your piston rings wore out or seals aged you would have more blow by in the crank case or when the pcv wore out your fuel trims would need to be updated.

I am on the stock 2g maf.

Which on these 3 methods would be best.

All delete the PCV valve.


1. 2 ins and vent

2. 2 ins and 1 out to the intake

3. 2 ins and 2 out to the intake

i think this is the important part of the conversation. No tunning, no wideband, no "speed density" option, dont vent it. To OP: 1 in 1 out both sides pcv after can on IM side.