CFM Performance Billet Valve Cover Breather Kit for 2002-2015 Mustang GT

I came across the CFM billet valve cover breather that replaces the oil filler cap and from my understanding includes a one way check ball valve that's supposedly fully compatible with the factory PCV system and designed to stay completely closed during normal driving conditions while under vacuum, but will then open at WOT/boost in order to relieve any unwanted crankcase pressure..

Anyway, I'd really appreciate any type of feedback from anyone who may be familiar with this breather kit or it's design concept..



In the meantime, thanks in advance...




-Rocky

Interesting, subscribed for the feedback.

And your point is ?

I have one on my whippled aluminator. It works just fine. Be ready for some oil misting. I also run valve cover breathers. Vac at idle id 18-20 and boost is where it is supposed to be.

I have one along with K&N valve cover breathers. 08 with a Kenne Bell 2.6L Blower. I haven't had any issues with the setup. You have to clean the filters from time to time. If you are driving with the windows down you can slightly smell the oil. No complaints from me though!

06 T-RED S/C GT said:

And your point is ?

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My point is I would like to know the answer to your question as well.

StangPhD said:

I have one on my whippled aluminator. It works just fine. Be ready for some oil misting. I also run valve cover breathers. Vac at idle id 18-20 and boost is where it is supposed to be.

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I'm actually surprised you also run valve cover breathers, as CFM does not recommend disabling the PCV system, as the CFM's pressure relief valve is designed to vent the crankcase with the PCV still fully intact..

I was also going to go the valve cover breather route, but after finding out about the PCV valve being integrated in the cam cover.. I really didn't want to go through the hassle of uninstalling the cam cover and then having to use a small cutting tool in order to remove the valve, so I decided that my best option was to just leave the PCV fully intact and try out the CFM breather kit along with the Bob's autosports oil separator..

So far at this point, both the CFM unit and catch can seem to be doing their jobs and haven't noticed any crankcase oil residue getting past the PCV connectors into the upper intake..

Hopefully this setup continues to work out, but if it doesn't ? Then I'll have no other option but to disable to factory PCV system altogether in favor of breathers

lemkau77 said:

I have one along with K&N valve cover breathers. 08 with a Kenne Bell 2.6L Blower. I haven't had any issues with the setup. You have to clean the filters from time to time. If you are driving with the windows down you can slightly smell the oil. No complaints from me though!

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Did you by any chance remove the PCV valve first before installing the K&N breathers ? From my understanding if the PCV valve is not removed ? the valve will stay closed if the vacuum line is disabled/capped off

Scott said:

My point is I would like to know the answer to your question as well.

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My apologies Scott ! As I misinterpreted your post and took it in the wrong way..

Anyway, so far the CFM breather kit does seem to be working along side with my Bob's oil separator, however I haven't ran my car at WOT or boost yet either, so I can't really say for sure how effective it is at this point..

So I'm hoping to get as many responses as possible from those who are either using the product or can chime in about it's pressure relief valve design

You don't have to remove anything in order to run open filters. Everyone does it without touching the PCV. Just put filters on both valve covers and in place of the oil cap. Install vacuum caps on the intake ports. Done. Nothing to it.

06 T-RED S/C GT said:

Did you by any chance remove the PCV valve first before installing the K&N breathers ? From my understanding if the PCV valve is not removed ? the valve will stay closed if the vacuum line is disabled/capped off

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I pulled the valve covers to remove the PCV from the passengers side, but didn't because I didn't want to have to cut into the cover on the underside. I might at some point down the road take it off cut it out and then weld it back up. I notice that one has a little more oil on the filter than the drivers side. The PCV will allow air to flow out of the valve cover, but not flow back in. On my car there is no PCV on the drivers side.

AbdullaGT500 said:

You don't have to remove anything in order to run open filters. Everyone does it without touching the PCV. Just put filters on both valve covers and in place of the oil cap. Install vacuum caps on the intake ports. Done. Nothing to it.

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How long have you been running breather filters and have you ever experienced any issues with oil vapor mist getting past the filters ?

lemkau77 said:

I pulled the valve covers to remove the PCV from the passengers side, but didn't because I didn't want to have to cut into the cover on the underside. I might at some point down the road take it off cut it out and then weld it back up. I notice that one has a little more oil on the filter than the drivers side. The PCV will allow air to flow out of the valve cover, but not flow back in. On my car there is no PCV on the drivers side.

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If your car is a GT500 ? which I assume is what you have ! Your PCV valve is located on the passenger side, opposite of the 3 valve 4.6 GT located on the driver's side.. Being that your GT500 is a 4 valve 5.4, this is why your PCV valve isn't located on the driver's side and would also explain the reason for noticing more oil on your passenger side filter..

My reason for trying out the CFM breather kit, is like yourself, I did not want to cut into the underside of my cam/valve cover in order to remove my PCV valve and as I mentioned earlier, it was my understanding that in order to run breather filters, the PCV system has to be completely disabled by not only capping off the vacuum lines, but also having to physically remove the PCV valve itself as well, otherwise running breather filters with the PCV valve still in place will only increase crankcase pressure build up due from the PCV valve not being able to allow enough airflow to flow out of the valve cover on it's own to vent the crankcase..

Perhaps the information I gathered was wrong ? but up until this point, it was really all I had to rely on at the time..

Supposedly the CFM breather has a one way check valve designed to properly vent the crankcase when under pressure, but at the same time is supposed to be fully compatible with the factory PCV system intact that will only allow air out, but not back into the crankcase as it opens during WOT or boost.. However under normal driving conditions and part throttle, the check valve is designed to stay closed while under PCV vacuum..

All I know other than what I've already mentioned, is the CFM breather kit replaces only the factory oil cap in order to vent the crankcase, but does not require disabling the factory PCV system nor does the company recommend running valve cover breathers.. Why, I don't know

06 T-RED S/C GT said:

How long have you been running breather filters and have you ever experienced any issues with oil vapor mist getting past the filters ?

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I ran it that way for a year or so before parting it out and selling the car. It was an 06 GT with built 3v motor and whipple supercharger. There as some oil vapor mist like others have said. It wasn't enough to bother me, but there was some.

AbdullaGT500 said:

I ran it that way for a year or so before parting it out and selling the car. It was an 06 GT with built 3v motor and whipple supercharger. There as some oil vapor mist like others have said. It wasn't enough to bother me, but there was some.

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It appears I'll need to reconsider after reading over your posts.. So if my current CFM setup doesn't work out ? Then I'll look into going full breathers..

One thing's for certain, I should had joined this site a long time ago, as you've all been more helpful addressing this issue than from those on other sites I've been on much longer

06 T-RED S/C GT said:

It appears I'll need to reconsider after reading over your posts.. So if my current CFM setup doesn't work out ? Then I'll look into going full breathers..

One thing's for certain, I should had joined this site a long time ago, as you've all been more helpful addressing this issue than from those on other sites I've been on much longer

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This is by far the best forum for these cars. You can find anything you need on here.

AbdullaGT500 said:

This is by far the best forum for these cars. You can find anything you need on here.

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I couldn't agree more

Not only do you get great info, you get to spend stupid amounts of money buying stuff you really don't need.....wait, maybe that is just me.

06 T-RED S/C GT said:

It appears I'll need to reconsider after reading over your posts.. So if my current CFM setup doesn't work out ? Then I'll look into going full breathers..

One thing's for certain, I should had joined this site a long time ago, as you've all been more helpful addressing this issue than from those on other sites I've been on much longer

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This just an FYI. I've ran a number of 3v supercharged setups. My experience is that the stock pcv system works just fine with forced induction. It's never caused any issues anyway, even up to 19psi.

The 3v crankcase ventilation system is designed to take air in from the passenger side and vent it through the driver side while keeping a vacuum on the system from the intake manifold.

People disagree on what's best for the motor. I'm of the opinion that the motor works best while the crankcase is under vacuum. The downside is that oil mist comes out with the crankcase air. An oil/air separator will go a long way to removing some of it but it won't get all of it. What does make it past the separator doesn't seem to affect anything.

I lived in the age of breathers on factory cars and don't want to go back, especially if it isn't necessary. The oil cap you referenced sounds like a good insurance policy to prevent overpressurization while still keeping the factory pcv system operational.

BruceH said:

People disagree on what's best for the motor. I'm of the opinion that the motor works best while the crankcase is under vacuum. The downside is that oil mist comes out with the crankcase air. An oil/air separator will go a long way to removing some of it but it won't get all of it. What does make it past the separator doesn't seem to affect anything.

I lived in the age of breathers on factory cars and don't want to go back, especially if it isn't necessary. The oil cap you referenced sounds like a good insurance policy to prevent overpressurization while still keeping the factory pcv system operational.

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I'll agree with this. I've had several GT500's and NEVER ran a catch can and never had any problems. Personally I think it's something you don't need. I did it on my 3v just to clean the engine bay up.