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Crank case breather vs catch can breather.

Ptrug

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What’s the difference and benefits between a crank case breather (oil cap style), and a catch can breather and do I need both?

19 GT ESS supercharger at 700hp.
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Boosted, I’d recommend a dual catch can setup. When you say catch can breather, are you talking closed loop or vent to atmosphere? I would always get a little oil misting with a breather venting to atmosphere.
 

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The valve cover and oil fill breathers will eventually piss oil vapor all over your engine bay, the catch can with a breather will not.
 

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I have the crank case breather and the vented catch can from UPR, Although I’m not boosted yet. I also have the hi flow PVC valve
 
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The valve cover and oil fill breathers will eventually piss oil vapor all over your engine bay, the catch can with a breather will not.
Yes. This my issue. Oil leaking on the engine. I wanted to know if having both breathers had more value then just one. While its all in a closed vacuum system, does the crank case breather offer more protection being right there in on the crankcase rather than allowing pressure to run through the hoses before it gets vented?
 

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Boosted, I’d recommend a dual catch can setup. When you say catch can breather, are you talking closed loop or vent to atmosphere? I would always get a little oil misting with a breather venting to atmosphere.
I have catch can on both driver and passenger since but they dont vent to atmosphere. I was wondering if there is a benefit to getting a venting catch can along with the crank case breather or is there no benefit?
 

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I assume you're looking at the CCM breather? They work but what happens is that dry filter material eventually soaks with oil and then starts spraying it everywhere.

If its a race car its a great solution because it will vent the gasses really easily, for a street driven car it will make your engine bay disguising really quickly.
 

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I ran a UPR VTA CC and the oil cap breather and never had an issue with oil in the engine bay. It also helped release any excess pressure built up since I was pushing around 18 psi with my ESS kit.
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Yes. This my issue. Oil leaking on the engine. I wanted to know if having both breathers had more value then just one. While its all in a closed vacuum system, does the crank case breather offer more protection being right there in on the crankcase rather than allowing pressure to run through the hoses before it gets vented?
In my opinion, when forced induction, you should have both valve covers plumbed to a catch can (either a single vented can with dual inputs, or a can for each valve cover) and the PCV valve replaced with a high flow port. Then, the port in the intake manifold and the port on the Air intake should be capped. This way, you have 0% shmeg going back into the engine.

PCV systems were primarily designed to recycle the crank case vapors/pressure back into the intake so that the fuel and oil was not being released into the atmosphere. Good for the environment, not so good for the engine.

When you are dealing with boost, the most critical time to relieve the crank case pressure is during boost, when the throttle is wide open. The blow by pressure from the Supercharger/turbo goes into the crank case, in addition to the pressure generated by the pistons thrashing up and down at high speed. This pressure needs a way to escape the engine, so by having free flowing ports to a catch can, all the pressure is relieved at the most critical moment.

The OEM PCV system only relieves crank case pressure during low engine speed/throttle closed events, because the system relies on intake manifold vaccum to suck the vapors/pressure out of the bottom end. This is fine for when you are just cruising down the highway, but does nothing to manage the pressure during boost when you need it most.
 

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I have both the UPR crank case breather and a Vented catch can on mine. Doesn't hurt to have both

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In my opinion, when forced induction, you should have both valve covers plumbed to a catch can (either a single vented can with dual inputs, or a can for each valve cover) and the PCV valve replaced with a high flow port. Then, the port in the intake manifold and the port on the Air intake should be capped. This way, you have 0% shmeg going back into the engine.

PCV systems were primarily designed to recycle the crank case vapors/pressure back into the intake so that the fuel and oil was not being released into the atmosphere. Good for the environment, not so good for the engine.

When you are dealing with boost, the most critical time to relieve the crank case pressure is during boost, when the throttle is wide open. The blow by pressure from the Supercharger/turbo goes into the crank case, in addition to the pressure generated by the pistons thrashing up and down at high speed. This pressure needs a way to escape the engine, so by having free flowing ports to a catch can, all the pressure is relieved at the most critical moment.

The OEM PCV system only relieves crank case pressure during low engine speed/throttle closed events, because the system relies on intake manifold vaccum to suck the vapors/pressure out of the bottom end. This is fine for when you are just cruising down the highway, but does nothing to manage the pressure during boost when you need it most.
Very insightful. Thank you.

Does having the crank case breather negate the need for the catch can breather? I understand it can't hurt to have both but is there a true benefit to having both or one over the other?
 

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Very insightful. Thank you.

Does having the crank case breather negate the need for the catch can breather? I understand it can't hurt to have both but is there a true benefit to having both or one over the other?
When not using the PCV system as the manufacturer intended, you want as much relief as possible. Ford didn't design these cars to have forced induction.

When running a non PCV system, you want the port and lines to the catch can as large as possible. The PCV valve in this scenario is just a restriction. UPR makes a replacement that gets rid of the valve with a wide open 5/8" port. Having the oil fill breather filter is great, as long as it isn't getting saturated, which will eventually make a mess. It really depends on how much boost you have. 10 PSI probably wont make a mess as long as the valve cover breathers are flowing properly. Crank it up to 18-20 PSI, and your gonna have a mess on your hands
 

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I have catch can on both driver and passenger since but they dont vent to atmosphere. I was wondering if there is a benefit to getting a venting catch can along with the crank case breather or is there no benefit?
If you have a can on both sides, you should be good. Like I said, I never had much luck running a breather as it will eventually start misting oil.
 
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When not using the PCV system as the manufacturer intended, you want as much relief as possible. Ford didn't design these cars to have forced induction.

When running a non PCV system, you want the port and lines to the catch can as large as possible. The PCV valve in this scenario is just a restriction. UPR makes a replacement that gets rid of the valve with a wide open 5/8" port. Having the oil fill breather filter is great, as long as it isn't getting saturated, which will eventually make a mess. It really depends on how much boost you have. 10 PSI probably wont make a mess as long as the valve cover breathers are flowing properly. Crank it up to 18-20 PSI, and your gonna have a mess on your hands
Thanks. I will get a catch can breather. Right now I have the ford performance oil separator on the passenger side and the J&L on driver side. Driver side is always bone dry but not passenger.

I am not sure exactly how much boost I have. A vacuum gauge is on the to do list. I can say that setup from manufacturer says 8psi (ESS G2 - 6PK 120mm (8PSI), Intercooler Size:G3 spec (40% larger)) and the crankcase breather frequently spits oil. I feel she is def more then 8psi... She is beast. I have had the supercharger on for about a year now.
 
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If you have a can on both sides, you should be good. Like I said, I never had much luck running a breather as it will eventually start misting oil.
Even the catch can? I am more interested in saving my engine and seals then oil stains.

My crankcase breather spits a lot of oil. I put a paper towel over it with rubber bands to catch the spit and replace it every once and awhile. I take if off if i ever go anywhere i'm going to show it etc...
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