Oil Breathers Uneven?

[06 T-RED S/C GT]

"CFM Performance valve cover breathers are the best money can buy and is the reason they have become extremely popular so quickly. They are so much more than a pretty filter on top of your valve cover and offer features that no other kits offer.

It is the only breather on the market which incorporates a check ball to keep unmetered air from coming through while the PCV system is active and the crankcase is under vacuum. In other words, this breather works just like a factory oil cap under normal driving conditions but will vent any positive crankcase pressure present under full or part throttle. It is also the only breather with an integrated baffle to help contain oil particles in the engine rather than allowing them to exit the valve cover and saturate the filter element. Filter tops are available in several popular powdercoat finishes, chrome, hydrocarbon and select OEM colors."

https://www.c-f-m.com/performanceparts/pc/Valve-Cover-Breathers-c744.htm

I can confirm beyond a shadow of a doubt the CFM billet oil cap breather does indeed function as advertised while keeping the factory PCV system active. After nearly 3 years, I've had zero crankcase oil vapors enter the intake manifold thanks to the CFM one way check ball valve which does indeed prevent unmetered air from entering the crankcase while under PCV vacuum and then opens to ventilate the crankcase under part and full throttle when PCV vacuum is temporarily closed. I also use the UPR 4-chamber catch can along with the CFM oil cap breather connected to the PCV port on the driver's side cam cover and into the intake manifold port. At one point, I did consider disabling the active PCV system altogether in favor of switching over to an open breather setup, but when I realized that the PCV valve is integrated into the driver's side cam cover, I didn't want going through all the hassle of having to cut open the PCV housing tube with a Dremel tool just in order to remove the PCV valve itself. Shortly after reading all the positive reviews about how effective the UPR 4 chamber catch can and CFM billet oil cap breathers worked in preventing crankcase oil vapors from entering the intake manifold/combustion chamber with the factory PCV system remaining active, I decided to give both a shot. Needless to say, I haven't looked back ever since.

 

[1950StangJump$]

So, in my case, I have a the straight tube running from the passenger side valve cover to the Kenne Bell intake tube. I have the PCV active, with a catch can running in between the driver's valve cover and the intake port.

Is the idea behind the CFM breather that I would leave the driver's side PCV and catch can in place as is, but close off the passenger side 'VC to intake tube' line in lieu of this breather as the oil cap? With the benefit being that I would have less blowby to be caught in the driver's side catch can?

Or would this breather be used as the oil cap and completely remove both the passenger side tube AND the driver's side catch can?

 

[JeremyH]

So, in my case, I have a the straight tube running from the passenger side valve cover to the Kenne Bell intake tube. I have the PCV active, with a catch can running in between the driver's valve cover and the intake port.

Is the idea behind the CFM breather that I would leave the driver's side PCV and catch can in place as is, but close off the passenger side 'VC to intake tube' line in lieu of this breather as the oil cap? With the benefit being that I would have less blowby to be caught in the driver's side catch can?

Or would this breather be used as the oil cap and completely remove both the passenger side tube AND the driver's side catch can?

Correct. No you can leave the passenger side hose to intake tube with if you like. It is essentially running to a breather already, ie the intake filter. You can run a open or closed system with the cfm cap. So you could leave everything else as is and just add the cap. Or open up the covers to filters or vented cans and fully "open" if you like as well.

 

[JeremyH]

Side note if you are boosted with a closed driver side set up I would highly reccomend a inline check valve. Other wise if the pcv (which is not a true checkvalve) fails or leaks you dont start pressurizing the crankcase under boost inadvertantly.

If you want some visuals of what the pcv looks like and how it functions heres a vid from when I removed mine and me rambling about my experience and research on the matter.

 

[JeremyH]

I would love to run their oil cap breather, but my intake tube runs passenger side right over the cap.

Other options would be to modify passenger fitting so its larger and remove pcv on driver side since that's sides larger but instead run to a vented catch can vice a closed catch can going to the manifold. That will ensure your venting better and continuously while wot/in boost.

 

[06 T-RED S/C GT]

Side note if you are boosted with a closed driver side set up I would highly reccomend a inline check valve. Other wise if the pcv (which is not a true checkvalve) fails or leaks you dont start pressurizing the crankcase under boost inadvertantly.

If you want some visuals of what the pcv looks like and how it functions heres a vid from when I removed mine and me rambling about my experience and research on the matter.

I forgot to mention that my UPR 4 chamber catch can does include an inline one-way check valve. My Saleen blower also includes a bypass valve as well which from my understanding also prevents the crankcase from pressurizing when under boost inadvertently

 

[JeremyH]

I forgot to mention that my UPR 4 chamber catch can does include an inline one-way check valve. My Saleen blower also includes a bypass valve as well which from my understanding also prevents the crankcase from pressurizing when under boost inadvertently

Most legit kits will but still quite a few companies have cans without them.

The blower bypass relieves pressure from manifold under low load/high vac idle decel cruise etc. When you put your foot in it the bypass closes and the pressure/boost stays in the manifold and goes to the engine. It's not crankcase/PVC related, its for drivability when you dont want boost since blower is always spinning.

 

[06 T-RED S/C GT]

Most legit kits will but still quite a few companies have cans without them.

The blower bypass relieves pressure from manifold under low load/high vac idle decel cruise etc. When you put your foot in it the bypass closes and the pressure/boost stays in the manifold and goes to the engine. It's not crankcase/PVC related, its for drivability when you dont want boost since blower is always spinning.

Jeremy, thanks very much for clarifying, as I now have a much better understanding of how the blower bypass valve functions. I also mentioned in my previous reply that my inline one-way check valve is routed from the catch can to the intake manifold. Is this the correct way or should the inline check valve run from the PCV inlet on the driver's side cam cover to the catch can?

 

[JeremyH]

Being on the manifold side or "pre" can makes more sense so your not pressurizing the can every time you get in boost.

 

[1950StangJump$]

Correct. No you can leave the passenger side hose to intake tube with if you like. It is essentially running to a breather already, ie the intake filter. You can run a open or closed system with the cfm cap. So you could leave everything else as is and just add the cap. Or open up the covers to filters or vented cans and fully "open" if you like as well.

So, if I leave everything as is, with the catch can and pvc on he driver's side VC, and the tube on the passenger side VC, but then add the cfm cap . . . is there a true benefit to be seen?

 

[06 T-RED S/C GT]

So, if I leave everything as is, with the catch can and pvc on he driver's side VC, and the tube on the passenger side VC, but then add the cfm cap . . . is there a true benefit to be seen?

Yes, that is correct. This is exactly how I have my mine setup as well. In other words, I have the inlet hose connected from the catch can to the PCV inlet tube on the driver's side VC and run the outlet side hose connected from the catch can to the intake manifold port. I keep the tube connected from the passenger side VC to the air/intake inlet tube that's attached to the throttle body. I've ran my setup this way with the CFM oil cap breather for over 3 years and the benefits have been phenomenal to say the very least.

 

[JeremyH]

So, if I leave everything as is, with the catch can and pvc on he driver's side VC, and the tube on the passenger side VC, but then add the cfm cap . . . is there a true benefit to be seen?

Yes huge difference just like T-red just mentioned. You will actually be venting the crankcase pressure properly when its needed most (when your boosting the motor). Then when you you let off the throttle and the manifold transitions from pressure to vac and the pcv does open for a little bit you dont have a rush of pressure forcing oil out through your can.

Like mentioned in my video the OEM pcv setup is for a na car for emmissions and to relieve normal blowby pressure. It does not function properly nor is it adequate to relieve the increased blowby pressure when you boost the motor.

And there is still a misconception that adding a inline can to catch oil fixes that problem when it's a seperate issue. You have 2 goals really, first is to fully vent the increased blowby pressure created by the increased cylinder pressure with boost. And then the second goal is to keep oil from going back in the manifold. Since oil/oil vapor does not combust it can dilute the air fuel mixture and create more carbon buildup over time.

The common methods to prevent oil going back in are opening the system and divorcing it from the manifold which prevents any oil from the crankcase from going back in. And second is using a inline oil seperator/catch can like you have to catch most of the oil before it reaches the manifold.

As mentioned make sure your can setup has a checkvalve like the upr setup etc.

 

[06 T-RED S/C GT]

Yes huge difference just like T-red just mentioned. You will actually be venting the crankcase pressure properly when its needed most (when your boosting the motor). Then when you you let off the throttle and the manifold transitions from pressure to vac and the pcv does open for a little bit you dont have a rush of pressure forcing oil out through your can.

Like mentioned in my video the OEM pcv setup is for a na car for emmissions and to relieve normal blowby pressure. It does not function properly nor is it adequate to relieve the increased blowby pressure when you boost the motor.

And there is still a misconception that adding a inline can to catch oil fixes that problem when it's a seperate issue. You have 2 goals really, first is to fully vent the increased blowby pressure created by the increased cylinder pressure with boost. And then the second goal is to keep oil from going back in the manifold. Since oil/oil vapor does not combust it can dilute the air fuel mixture and create more carbon buildup over time.

The common methods to prevent oil going back in are opening the system and divorcing it from the manifold which prevents any oil from the crankcase from going back in. And second is using a inline oil seperator/catch can like you have to catch most of the oil before it reaches the manifold.

As mentioned make sure your can setup has a checkvalve like the upr setup etc.

Jeremy, would you still recommend removing the PCV valve from the driver's side cam cover, even though my UPR can setup has an inline check valve along with having the CFM oil cap breather in place? Therefore, if you would still recommend removing it? can you walk me through step by step how to go about removing it and then how to go about re-sealing the PCV valve housing tube after cutting it open? Thanks once again, Rocky

 

[1950StangJump$]

Yes huge difference just like T-red just mentioned. You will actually be venting the crankcase pressure properly when its needed most (when your boosting the motor). Then when you you let off the throttle and the manifold transitions from pressure to vac and the pcv does open for a little bit you dont have a rush of pressure forcing oil out through your can.

Like mentioned in my video the OEM pcv setup is for a na car for emmissions and to relieve normal blowby pressure. It does not function properly nor is it adequate to relieve the increased blowby pressure when you boost the motor.

And there is still a misconception that adding a inline can to catch oil fixes that problem when it's a seperate issue. You have 2 goals really, first is to fully vent the increased blowby pressure created by the increased cylinder pressure with boost. And then the second goal is to keep oil from going back in the manifold. Since oil/oil vapor does not combust it can dilute the air fuel mixture and create more carbon buildup over time.

The common methods to prevent oil going back in are opening the system and divorcing it from the manifold which prevents any oil from the crankcase from going back in. And second is using a inline oil seperator/catch can like you have to catch most of the oil before it reaches the manifold.

As mentioned make sure your can setup has a checkvalve like the upr setup etc.

Great info.

My can does not have a check valve, but I was under the impression it is unneeded with the PVC is functioning?

Or would the addition of the CFM oil cap necessitate the check valve addition?

 

[JeremyH]

Jeremy, would you still recommend removing the PCV valve from the driver's side cam cover, even though my UPR can setup has an inline check valve along with having the CFM oil cap breather in place? Therefore, if you would still recommend removing it? can you walk me through step by step how to go about removing it and then how to go about re-sealing the PCV valve housing tube after cutting it open? Thanks once again, Rocky

Really no need to unless you want to vent better and/or going to a open setup.

All I did was basically cut out 3 sides of a square with a dremel and then pryed open the flap with a screwdriver. Once the valve was out I bent the flap back shut.

As mentioned earlier there are a few threads on ways to do it on the forum if you search.

 

[JeremyH]

Great info.

My can does not have a check valve, but I was under the impression it is unneeded with the PVC is functioning?

Or would the addition of the CFM oil cap necessitate the check valve addition?

The impression your under would be wrong.
The only time you would run a non check valved can would be on a naturally aspirated setup. The pcv valve is a spring loaded plunger valve that is shut under manifold vaccum and opens when vac is low (wot) to vent crankcase pressure. It is not a one direction pressure checkvalve.

I'm trying to not repeat myself over and over but as I mentioned the PVC no longer functions as designed when your boosted. Again watch the video I posted maybe that will help you better. The pcv is not a checkvalve and was never designed to have to fight boost pressure coming from the manifold going into the valve cover through the pcv valve. It functions the opposite way when na vac greater than 2-4" in the manifold going through the line to the pcv valve pulls out the plunger and shuts it.

So yes 100% if your driver side setup is closed and you have boost you want a check valve to protect the engine from that pressure.

The cfm cap breather does help to vent the case but does nothing in the way of keeping you from forcing air from the manifold through the hose through your can and past the pcv and back into the case when your in boost. This pressure actually forces the pcv full open(plunger all the way in)when your in boost. Which you dont want as now instead of venting case your forcing air in past the plunger and valve seat of the pcv. An actual checkvalve would prevent this.

 

[1950StangJump$]

Alright thank you

 

[JeremyH]

No prob.

 

[06 T-RED S/C GT]

Really no need to unless you want to vent better and/or going to a open setup.

All I did was basically cut out 3 sides of a square with a dremel and then pryed open the flap with a screwdriver. Once the valve was out I bent the flap back shut.

As mentioned earlier there are a few threads on ways to do it on the forum if you search.

Usually, I do search the forums, Jeremy. However, knowing the info you've been providing here on this thread regarding the pros and cons between closed and open ventilation setups, I figured that by requesting your feedback for how you went about removing the PCV valve from your perspective would also be considered as useful and relevant in part towards the thread topic. At any rate, if there's really no need for removing the PCV valve providing there's an inline check valve in place, as you just brought up, then I'll just leave the PCV valve in place at least for the time being anyhow. In the meantime, thanks once again for all your support and feedback.

 

[Mustang dog]

Hi Jeremy, I am going to do the pcv delete, I have the 2 k&n breathers, plus I have the breather for the oil cap, ( cfm and a full on non ballcock style from metco)
Instead of capping off the pcv inlet into the intake manifold, could I use this to pull vaccum for my BOV? I am thinking this a great spot for vaccum, over the brake booster vaccum line I have. Specifically because it is a shorter run to my BOV i have mounted at the front on my hot side to intercooler, on my Paxton 2200sl.