PCV and catch can question
Thread Starter
Safety Car
Joined: Feb 1999
Posts: 4,043
Likes: 342
From: Central NJ
PCV and catch can question
Does the catch can adversly affect the PCV operation? The PCV is on for a reason so I am wondering if in the long run the catch can is doing more harm then good. Anybody test these tings to be sure?
Thanks
Thanks
Team Owner
Joined: May 2001
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
A properly installed catch can is not eliminating the pcv system. Not sure what you're asking.
Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
Not sure if you've taken a look at a catch can but it does just what its name implies.
When the system works as designed, oil is fed back into the intake and burns off but leaves residue. The catch can adds a couple of hoses and channels that oil into the can and deposits it safely out of the way.
If your question is does the engine/intake need that oil, the answer is a definite no.
Make sure you hook it up correctly though. We had a few tense days a while ago when one member fed water into his engine by hooking up the wrong hoses.
When the system works as designed, oil is fed back into the intake and burns off but leaves residue. The catch can adds a couple of hoses and channels that oil into the can and deposits it safely out of the way.
If your question is does the engine/intake need that oil, the answer is a definite no.
Make sure you hook it up correctly though. We had a few tense days a while ago when one member fed water into his engine by hooking up the wrong hoses.
Drifting
Joined: Feb 2007
Posts: 1,993
Likes: 7
From: LaPine Oregon
They met with little or no resistance.............
The catch can or tank or coalescing filter ( which I use) is simply put inline after the PVC valve that is routed back to the intake. I doubt that any backpressure or resistance added at all.
I personally don't have an excess oil issue with either my 2000 or 2001 C5s but added the oil catch can to remove any oil vapor ( as all engines have oil vapor to some degree). I don't need that building up on my intake, valves or pistons. Besides alot of factory cars , foreign and domestic have catch cans, particulary turbo cars.
As some have alluded to, not all catch cans are created equal that's for sure.
Last edited by dieseldave56; Sep 9, 2007 at 02:53 AM.
Thread Starter
Safety Car
Joined: Feb 1999
Posts: 4,043
Likes: 342
From: Central NJ
Thanks. I understand how the PCV works and the fact that the oil going into the intake is not the best thing. I also understand the reason why the catch cans are installed. I was more concerned with the actual crankcase ventilation and the possiblity that the catch can filters can be too restrictive for the PCV to actually work properly...I guess this may be the case for a filter that has been in the can for thousands of miles without replacement or cleaning...Any thoughts on this??
Thanks
The catch can or tank or coalescing filter ( which I use) is simply put inline after the PVC valve that is routed back to the intake. I doubt that any backpressure or resistance added at all.
I personally don't have an excess oil issue with either my 2000 or 2001 C5s but added the oil catch can to remove any oil vapor ( as all engines have oil vapor to some degree). I don't need that building up on my intake, valves or pistons. Besides alot of factory cars , foreign and domestic have catch cans, particulary turbo cars.
As some have alluded to, not all catch cans are created equal that's for sure.
Thanks
The catch can or tank or coalescing filter ( which I use) is simply put inline after the PVC valve that is routed back to the intake. I doubt that any backpressure or resistance added at all.
I personally don't have an excess oil issue with either my 2000 or 2001 C5s but added the oil catch can to remove any oil vapor ( as all engines have oil vapor to some degree). I don't need that building up on my intake, valves or pistons. Besides alot of factory cars , foreign and domestic have catch cans, particulary turbo cars.
As some have alluded to, not all catch cans are created equal that's for sure.
Melting Slicks
Joined: May 2000
Posts: 2,498
Likes: 4
From: Brentwood TN
Use a catch can that does not have a filter element, but rather relies on the volume of the catch can to permit oil droplets to condense and collect.
To answer the original question, a non-filter catch can introduces a modest additional pressure drop (delta p or dp) by virtue of the fact that the vacuum line is longer and there is a slight dp across the fittings on the can. However, flow rates are low enough that the additional dp is inconsequential.
A catch can with a filter element introduces greater dp and as the oil collects on the filter element the dp increases. I don't know how much dp the system can tolerate before it affects performance or sets a code. Maybe someone else reading this might know.
Charlie
To answer the original question, a non-filter catch can introduces a modest additional pressure drop (delta p or dp) by virtue of the fact that the vacuum line is longer and there is a slight dp across the fittings on the can. However, flow rates are low enough that the additional dp is inconsequential.
A catch can with a filter element introduces greater dp and as the oil collects on the filter element the dp increases. I don't know how much dp the system can tolerate before it affects performance or sets a code. Maybe someone else reading this might know.
Charlie
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Thread Starter
Safety Car
Joined: Feb 1999
Posts: 4,043
Likes: 342
From: Central NJ
It appears as though the popular catch cans for the C5 have some type of filter or mesh type stuff. I have to wonder about how much testing was done on these things. I have never seen anybody provide any type of testing other then the fact that oil collects in the can. Is this all the oil or is some oil still getting into the intake? Well I am glad you understood my original question as it seemed to be somewhat confusing....Thanks
Use a catch can that does not have a filter element, but rather relies on the volume of the catch can to permit oil droplets to condense and collect.
To answer the original question, a non-filter catch can introduces a modest additional pressure drop (delta p or dp) by virtue of the fact that the vacuum line is longer and there is a slight dp across the fittings on the can. However, flow rates are low enough that the additional dp is inconsequential.
A catch can with a filter element introduces greater dp and as the oil collects on the filter element the dp increases. I don't know how much dp the system can tolerate before it affects performance or sets a code. Maybe someone else reading this might know.
Charlie
To answer the original question, a non-filter catch can introduces a modest additional pressure drop (delta p or dp) by virtue of the fact that the vacuum line is longer and there is a slight dp across the fittings on the can. However, flow rates are low enough that the additional dp is inconsequential.
A catch can with a filter element introduces greater dp and as the oil collects on the filter element the dp increases. I don't know how much dp the system can tolerate before it affects performance or sets a code. Maybe someone else reading this might know.
Charlie
Melting Slicks
Joined: May 2000
Posts: 2,498
Likes: 4
From: Brentwood TN
It appears as though the popular catch cans for the C5 have some type of filter or mesh type stuff. I have to wonder about how much testing was done on these things. I have never seen anybody provide any type of testing other then the fact that oil collects in the can. Is this all the oil or is some oil still getting into the intake? Well I am glad you understood my original question as it seemed to be somewhat confusing....Thanks
Charlie
Race Director
Joined: Dec 2000
Posts: 19,304
Likes: 85
From: San Diego CA
It appears as though the popular catch cans for the C5 have some type of filter or mesh type stuff. I have to wonder about how much testing was done on these things. I have never seen anybody provide any type of testing other then the fact that oil collects in the can. Is this all the oil or is some oil still getting into the intake? Well I am glad you understood my original question as it seemed to be somewhat confusing....Thanks
http://www.conceptualpolymer.com/PCV...oval%20101.pdf
Let me know if you have any questions after reading my article. The long story - short is that most catch cans' filter media is not sized (density-wise) correctly for the flow and pressure that is found in an LS1 or LS6 PCV setup. It's somewhat akin to using a 100 CFM filter for a 1.3 CFM system. Yes, it will catch some of the oil,but not very efficiently.
Thread Starter
Safety Car
Joined: Feb 1999
Posts: 4,043
Likes: 342
From: Central NJ
Well Dave I think you pretty much answered my question. Thanks very much...
I know one guy who has done a bit of testing.......
http://www.conceptualpolymer.com/PCV...oval%20101.pdf
Let me know if you have any questions after reading my article. The long story - short is that most catch cans' filter media is not sized (density-wise) correctly for the flow and pressure that is found in an LS1 or LS6 PCV setup. It's somewhat akin to using a 100 CFM filter for a 1.3 CFM system. Yes, it will catch some of the oil,but not very efficiently.
http://www.conceptualpolymer.com/PCV...oval%20101.pdf
Let me know if you have any questions after reading my article. The long story - short is that most catch cans' filter media is not sized (density-wise) correctly for the flow and pressure that is found in an LS1 or LS6 PCV setup. It's somewhat akin to using a 100 CFM filter for a 1.3 CFM system. Yes, it will catch some of the oil,but not very efficiently.
Drifting
Joined: Feb 2007
Posts: 1,993
Likes: 7
From: LaPine Oregon
Dave68 does it again...........
I was just going to post that link from my 'favorites' list that Dave68 addressed . Dave turned my on to it many months ago. Way to go Dave.
That article and Dave's experience led me to the design that I finally ended up with. Adding over sized fittings and plumbing hoses ( stock plumbibg being 5/16 ID) also reduced the chance of increased back pressure in PVC system.
That article and Dave's experience led me to the design that I finally ended up with. Adding over sized fittings and plumbing hoses ( stock plumbibg being 5/16 ID) also reduced the chance of increased back pressure in PVC system.
