Catch can system need PCV?
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Pro
Joined: Sep 2011
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From: Tampa Fl
Catch can system need PCV?
I just installed a CCA oil catch can and was wondering if i need to use the stock PCV valve in conjuncture with the catch can system? My guess is yes, but wanted to get some more opinions. Also I have seen people running two catch cans (crankcase and valve cover), is there any merit to this? Especially considering the valve covers and crank case are connected. 
Tech Contributor
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
The PCV is a vacuum regulating device that is tuned to allow the CORRECT amount of vacuum in the crankcase at different throttle positions.
If you do not use a PCV valve, the throttle blade will be slammed shut at idle because you getting excessive air bypassing the throttle blade. You will have a very rough transition from IDLE to just OFF IDLE part throttle.
YES,, you need to use a PCV valve.
BC
If you do not use a PCV valve, the throttle blade will be slammed shut at idle because you getting excessive air bypassing the throttle blade. You will have a very rough transition from IDLE to just OFF IDLE part throttle.
YES,, you need to use a PCV valve.
BC
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2020 Corvette of the Year Finalist (performance mods)
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yes you still need the pcv valve... i have a dual can on mine from saikoumichi (sp)... the second can is supposed to help with constant high rpm use which my car doesn't see... i bought this can maybe 3-4 years ago and at the time was the best one i could find on the market... i think the single can setups will do just fine for most of us on here
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From: New Market AL
Without a PCV (check valve) you will be drawing crankcase air constantly at idle and low manifold pressure cruise. This airflow is un-metered, entering the intake downstream of the MAF. Depending on how your car is tuned, more than likely you will peg out your idle fuel trims as the ECM tries to compensate for the un-metered air. You will also be pulling excess oil vapor through your catch can and intake manifold.
