2.7 catch can?

[beachman101]

So i have been delving deeper into off road youtube and they say that a catch can is a really good idea for off road vehicles. I vaguely remember a discussion here about it.

What do the experts think? is it needed? does it help? is the modern 2.7 advanced enough that it doesnt need it?

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[Wanted33]

The 2.7L will have "port", and "direct" injection. So, a catch can really isn't needed unless you want one.

 

[beachman101]

The 2.7L will have "port", and "direct" injection. So, a catch can really isn't needed unless you want one.

ya thats what i was wondering if it was related to that

 

[jjack50]

So i have been delving deeper into off road youtube and they say that a catch can is a really good idea for off road vehicles. I vaguely remember a discussion here about it.

What do the experts think? is it needed? does it help? is the modern 2.7 advanced enough that it doesnt need it?

The vehicles that benefit from a catch can have higher performance engines that significantly increase crankcase pressures by causing more cylinder blow-by and are direct injected. The 2.7 is not one of those engines and in addition, has port injection in addition to direct which washes the intake channel and valve where carbon could build up.
So, there is no necessity to add a catch can to the 2.7. I know the 2.3 in the Ranger has a built-in air/oil separator that accomplishes most of what a catch can could. I don’t know if the 2.7 also has one.

 

[broncorik]

The vehicles that benefit from a catch can have higher performance engines that significantly increase crankcase pressures by causing more cylinder blow-by and are direct injected. The 2.7 is not one of those engines and in addition, has port injection in addition to direct which washes the intake channel and valve where carbon could build up.
So, there is no necessity to add a catch can to the 2.7. I know the 2.3 in the Ranger has a built-in air/oil separator that accomplishes most of what a catch can could. I don’t know if the 2.7 also has one.

Interesting video:

 

[jjack50]

Interesting video:

Watched the vid. There are some issues with it. Many cars before PCV had a breather cap which was usually on the top of a valve cover that vented vapors directly to the air. With the onset of PCV, the first versions just replaced the breather with a plug that had a hose that plumbed the extra pressure to the intake including any oil droplets or other liquids that might be entrained in the vapor stream. Carburetors or port injection washed the ports so there wasn't a big problem.
Blow-by doesn't just leisurely drift down into the crankcase. There are rings on the pistons for a reason. Most of the extra pressure from combustion is stopped by the rings but some will always get by into the crankcase. The amount that gets by is determined by the overpressure in the cylinder during combustion. Forced induction -above designed in pressures- or any method of significantly increasing the performance of an engine will increase blow-by. That's the reason vapor separators (also called air-oil separators) are included for higher performance engines. Some engines include a vapor separator that runs the removed liquid back into the crankcase. Others include a container that will need to be emptied from time to time.
In any case, the remaining vapors will continue through the hoses to be introduced into the intake system. Unlike what this guy said, it is not clean air that comes out of a catch can and goes into the intake. it is gases that are not liquid and thus not removed by the catch can. This includes oil vapors, combustion gases, gasoline vapors, and others all of which will be burned or blown out through the exhaust or blown-by back to the crankcase.

Anyway, The best catch can is the one that makes an owner happy by doing its job with the least amount of fiddling and the least amount of maintenance.

 

[broncorik]

Watched the vid. There are some issues with it. Many cars before PCV had a breather cap which was usually on the top of a valve cover that vented vapors directly to the air. With the onset of PCV, the first versions just replaced the breather with a plug that had a hose that plumbed the extra pressure to the intake including any oil droplets or other liquids that might be entrained in the vapor stream. Carburetors or port injection washed the ports so there wasn't a big problem.
Blow-by doesn't just leisurely drift down into the crankcase. There are rings on the pistons for a reason. Most of the extra pressure from combustion is stopped by the rings but some will always get by into the crankcase. The amount that gets by is determined by the overpressure in the cylinder during combustion. Forced induction -above designed in pressures- or any method of significantly increasing the performance of an engine will increase blow-by. That's the reason vapor separators (also called air-oil separators) are included for higher performance engines. Some engines include a vapor separator that runs the removed liquid back into the crankcase. Others include a container that will need to be emptied from time to time.
In any case, the remaining vapors will continue through the hoses to be introduced into the intake system. Unlike what this guy said, it is not clean air that comes out of a catch can and goes into the intake. it is gases that are not liquid and thus not removed by the catch can. This includes oil vapors, combustion gases, gasoline vapors, and others all of which will be burned or blown out through the exhaust or blown-by back to the crankcase.

Anyway, The best catch can is the one that makes an owner happy by doing its job with the least amount of fiddling and the least amount of maintenance.

The manufacturers will always try to oversimplify...but what I can share is that my catch can has kept a lot of oil out of places oil should not be going. The best way to determine potential effectiveness for newer 2.3s and 2.7s is to review feedback from folks who are currently running them on post-2018s. If they are getting any oil of them, like in the video for the 3.5, that suggests a benefit for running a catch can. The rest is just theory at that point...the guy who wrote the PDF I attached was a 50 year master mechanic for MB, and he said there was a significant improvement on any turbo engine using a catch can with longevity and eventual cost savings.

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