Oil Separator

[JustRaptor1]

I pulled the trigger, just ordered the JLT!

 

[CigarPundit]

With dual "out" ports or valves in conjunction with check valves (to prevent any backflow through the PCV system and the Catch Can itself) the first "in" valve will use the intake manifold vacuum for evacuation suction when at idle. The second "out" valve will tap into the area in front of the throttle body for the suction needed to continue evacuation when accelerating or going WOT (wide open throttle).

https://www.mcnallyelectronics.com/...lve-Oil-Catch-Can-vs-a-Single-Valve_b_13.html

I understand the theory of operation. What I don’t understand is how you would get crank case vapor in your intake that hasn’t passed through the catch can(s) in a two valve system.

 

[MEATSWORD]

I understand the theory of operation. What I don’t understand is how you would get crank case vapor in your intake that hasn’t passed through the catch can(s) in a two valve system.

The second port is hooked in front of the turbos so that when under boost the crankcase is still under vacuum.
There are some check valves in the mix so you don't pressurise the separator.

 

[pbtjrlmrt]

I understand the theory of operation. What I don’t understand is how you would get crank case vapor in your intake that hasn’t passed through the catch can(s) in a two valve system.

It's not that your getting crankcase vapor that hasn't passed through the catch can. whether it's a single or dual valve all VENTILATED crankcase vapor passes through the catch can. THe problem is that under WOT(Wide Open Throttle or hard throttle ) the single valve system doesn't create enough vacuum to pull crank case blow by. You need the additional vacuum created elsewhere in the intake system to help create enough vacuum to help the crank case ventilated. The single valve system works but it only works under idle and light throttle application....it's a half arse approach and doesn't provide as much benefit as the dual valve setup does.

In this conversation NEED is too strong of a word. THe system works fine without any catch can at all. It's just that if your going to spend the time and money to improved the quality of your intake air to achieve better efficiency/power/longevity then why not go all the way....Similar to air filter...why would you put in a substandard air filter...sure it provides more benefit over having nothing but if it's doesn't work as well as something else which would you choose?

 

[K223]

Have any of the forum tuners weighed in on the value of catch cans, and shown in graphs power gains made with the cleaner air? Or is the power gain not noteworthy and the cleaner air in your engine Is just better for longevity of the entire induction system to be able to provide the same performance many miles down the road?

Yes I’m sitting on a picket fence right now.

 

[pbtjrlmrt]

Have any of the forum tuners weighed in on the value of catch cans, and shown in graphs power gains made with the cleaner air? Or is the power gain not noteworthy and the cleaner air in your engine Is just better for longevity of the entire induction system to be able to provide the same performance many miles down the road?

Yes I’m sitting on a picket fence right now.

I've not seen any graphs and would lean more to the latter rather than the former. Oil laced air being induced into the engine would obviously be less preferable than clean air...after that...with the valve coaking issue resolved by adding port injection....the cleaner running/longevity issue is what grabs me...although....plenty of graphs show the benefits of higher octane fuel in our ecoboost and oil laced air will definitely reduce octane...measurable on a dyno?...not sure but I opt for have the cleanest running system possible....same reason I keep the air filters changed...LOL

 

[CigarPundit]

It's not that your getting crankcase vapor that hasn't passed through the catch can. whether it's a single or dual valve all VENTILATED crankcase vapor passes through the catch can. THe problem is that under WOT(Wide Open Throttle or hard throttle ) the single valve system doesn't create enough vacuum to pull crank case blow by. You need the additional vacuum created elsewhere in the intake system to help create enough vacuum to help the crank case ventilated. The single valve system works but it only works under idle and light throttle application....it's a half arse approach and doesn't provide as much benefit as the dual valve setup does.

In this conversation NEED is too strong of a word. THe system works fine without any catch can at all. It's just that if your going to spend the time and money to improved the quality of your intake air to achieve better efficiency/power/longevity then why not go all the way....Similar to air filter...why would you put in a substandard air filter...sure it provides more benefit over having nothing but if it's doesn't work as well as something else which would you choose?

I appreciate that you are trying to explain it to me, but frankly, your answer only reinforces my logic (or perhaps, lack of understanding) that dual valve accomplishes nothing. You stated: "whether it's a single or dual valve all VENTILATED crankcase vapor passes through the catch can. THe problem is that under WOT(Wide Open Throttle or hard throttle ) the single valve system doesn't create enough vacuum to pull crank case blow by." My point is as follows:

The reason to have a catch can is simply to prevent coking of the intake valves caused by ingestion of oil vapor, condensation, and other crud from the crankcase gasses that the PCV system circulates back into the intake. If the PCV system isn't doing that under throttle or WOT due to the lack of vacuum, then that's fine--your intake valves are not getting exposed to the crankcase gasses in this condition, so no coking is going to occur. From what I have heard/read, a two valve system induces more crankcase ventilation into the intake tract when it would not otherwise exist. Maybe that will result in filling your catch can quicker, but it won't do a damn thing to prevent intake valve coking. If anything, it would make matters worse by inducing more crankcase ventilation than would otherwise exist, notwithstanding the can's filtering effect, which might not be 100% effective.

In short, as long as all crankcase gasses are passing through the catch can, mission accomplished. I don't see how a dual valve helps things.

I remain open minded, but nothing I have yet heard contradicts my reasoning.

 

[SRPRACING]

The stock pcv system is more than adequate to ventilate the blow by. Under light acceleration or idle it evacuates into the intake. But when wot the pcv check valve closed to not pressurize the crankcase and then proceeds to ventilate outside of the clean side if needed. Hence why you see the driver turbo inlet always oily. Completely normal.

You really only need a catch can on the passenger side. You can go all out for both sides but in theory passenger is more than enough.

The fear of valve coking and oil filled air is very very exaggerated. Here and there you might get less KR but it’s very unnoticeable. Anyone that says it increase hp is a bunch of crap. Your vehicle will be just fine without a catch can. Many cases people actually have a boost leak running the dual valve as they never seem to connect seamlessly as does stock. And if you don’t then good for you.

Believe what you want. Keep in mind having a dual valve system fail can lead to more problems then some valve coking. Talking pressurizing the crankcase and blowing seals. Having a single sided catch can is a safe call as there is less to go wrong.

Last thing being even most catch cans still let oil thru. You’re not going to catch everything.

 

[CigarPundit]

The stock pcv system is more than adequate to ventilate the blow by. Under light acceleration or idle it evacuates into the intake. But when wot the pcv check valve closed to not pressurize the crankcase and then proceeds to ventilate outside of the clean side if needed. Hence why you see the driver turbo inlet always oily. Completely normal.

You really only need a catch can on the passenger side. You can go all out for both sides but in theory passenger is more than enough.

The fear of valve coking and oil filled air is very very exaggerated. Here and there you might get less KR but it’s very unnoticeable. Anyone that says it increase hp is a bunch of crap. Your vehicle will be just fine without a catch can. Many cases people actually have a boost leak running the dual valve as they never seem to connect seamlessly as does stock. And if you don’t then good for you.

Believe what you want. Keep in mind having a dual valve system fail can lead to more problems then some valve coking. Talking pressurizing the crankcase and blowing seals. Having a single sided catch can is a safe call as there is less to go wrong.

Last thing being even most catch cans still let oil thru. You’re not going to catch everything.

It's all true. The 3.5L ecoboost has both direct injectors and intake port injectors, so the valves benefit from fuel rinsing that direct injection-only engines do not. This will mitigate intake valve coking, and it's probably not that big a deal in the first place. I place my catch cans in the same category as my frequent oil changes. Is it necessary? Probably not. Do I like doing it for peace of mind and entertainment? Absolutely.

 

[pbtjrlmrt]

When facts are ignored and "beliefs" rule the day then the discussion is over...at least for me. I've made the point repeatedly that it's NOT about valve coaking and that the main benefit is cleaning the air as much as possible of any oil residue resulting from blow by. It's about overall cleaner running and preserving fuel octane.

Fact: A dual valve will clean better than a single valve during high acceleration.
Fact: Lower octane reduces HP
Fact: less oil being taken into the intake system is better all around
Fact: Beliefs don't change facts...LOL

The information is out there. The physics are proven. The HP gains from higher octane are documented. Cleaner air intake benefit should be obvious.
It's obviously your time and your money and your vehicle. You can lead a horse to water but you can't make em drink.

Been interesting for sure..................