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Catch can and check valve for boost?

7.1K views 9 replies 6 participants last post by  crazymikemma  
#1 ·
Just about finished with my engine rebuild, transmission rebuild, and supercharger build.. my tech swears if I'm going to use my catch can I will need a check valve installed in line or I'll pressurize the crankcase. Is this true? I mean, there's no valve if I just ran without the catch can.. just curious

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#2 ·
PCV valve acts as a check valve, however we know they can fail (gum up....). If the valve sticks open boost will pump into the crankcase, assuming your still plumbed to the intake manifold. On all my turbo cars I just skipped plumbing it to the manifold and ran a tube to just below my chassis. You could just plumb to the catch can and vent to atmosphere.
 
#3 ·
not sure why, who else does that, well some may do that . but i never was recommended on a check valve. got to be cheap.

anyone else use that????
 
#4 ·
He's running an impressive turbo mustang, so I wasn't sure if it was more a 4.6 problem or a general rule..

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#7 ·
Yes you need to keep the manifold pressure out of the catch can. However at wot/high manifold pressure is when you need the catch can the most so you can see the issue with doing it that way. Or you can run the catch can to the inlet side of the blower and not need a check valve. But running a closed pcv system is not ideal any performance build. I would suggest running a vented/open air catch can (easier anyway)
 
#8 ·
So just put a breather on the outlet of the catch can and plug the manifold inlet? Or you just letting the hose hang down?

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#10 ·
Yea I have the speedlogix one. Had it before starting the build.

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