Check valve: with or without pcv valve?
Check valve: with or without pcv valve? For those of you with a check valve in the pcv line, did you keep the pcv valve or loose it? Seems to me that the check valve would be doing the same thing as the pcv so I could loose the pcv valve all together....?
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Joined: Nov 2001
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From: Las Cruces, NM
Originally Posted by xssive
For those of you with a check valve in the pcv line, did you keep the pcv valve or loose it? Seems to me that the check valve would be doing the same thing as the pcv so I could loose the pcv valve all together....?
You still want the pcv to limit the flow into the intake manifold unless the check valve flows the same or slightly less.
Gary
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Joined: Nov 2001
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From: Centrifugal City
You want to limit vacuum?
I thought crankcase vacuum was good?
I run my check valve without a PCV.
It's just an improved/stronger PCV, eh?
I have higher vacuum with just the check valve and no PCV at idle, noting the increased airflow from the SC over stock. After I get into boost, my passenger breather should help when the check valve closes.
My mech wants me to place the routed valve breather near the main air filter for some minor vacuum when under boost/WOT as opposed to routing the fresh air line w/o breather into the intake tract in front of the SC. Oil could get sucked out of the valve covers under WOT and back into the intake lowering octane, ingesting oil, etc.
I thought crankcase vacuum was good?
I run my check valve without a PCV.
It's just an improved/stronger PCV, eh?
I have higher vacuum with just the check valve and no PCV at idle, noting the increased airflow from the SC over stock. After I get into boost, my passenger breather should help when the check valve closes.
My mech wants me to place the routed valve breather near the main air filter for some minor vacuum when under boost/WOT as opposed to routing the fresh air line w/o breather into the intake tract in front of the SC. Oil could get sucked out of the valve covers under WOT and back into the intake lowering octane, ingesting oil, etc.
Last edited by MelloYellow; Sep 30, 2004 at 12:44 AM.
TECH Fanatic
Joined: Nov 2001
Posts: 1,190
Likes: 0
From: Las Cruces, NM
Originally Posted by MelloYellow
You want to limit vacuum?
I thought crankcase vacuum was good?
I run my check valve without a PCV.
It's just an improved/stronger PCV, eh?
I have higher vacuum with just the check valve and no PCV at idle, noting the increased airflow from the SC over stock. After I get into boost, my passenger breather should help when the check valve closes.
My mech wants me to place the routed valve breather near the main air filter for some minor vacuum when under boost/WOT as opposed to routing the fresh air line w/o breather into the intake tract in front of the SC. Oil could get sucked out of the valve covers under WOT and back into the intake lowering octane, ingesting oil, etc.
I thought crankcase vacuum was good?
I run my check valve without a PCV.
It's just an improved/stronger PCV, eh?
I have higher vacuum with just the check valve and no PCV at idle, noting the increased airflow from the SC over stock. After I get into boost, my passenger breather should help when the check valve closes.
My mech wants me to place the routed valve breather near the main air filter for some minor vacuum when under boost/WOT as opposed to routing the fresh air line w/o breather into the intake tract in front of the SC. Oil could get sucked out of the valve covers under WOT and back into the intake lowering octane, ingesting oil, etc.
It depends on the check valve. If you have a high flow check valve and no pcv you will have more unmetered air into the engine than with a stock pcv. This means the computer has to work harder to maintain the fuel trims.
Gary
