Catch Can Q's

Turbo and Supercharger discussion
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Catch Can Q's

By BLaCkSiLo
- Fri Jul 24, 2009 2:30 pm #132987 so i was just wondering when you need to implement a catch can into your boosted setup? i know that it is supposed to catch the oil/spent fuel/vapors but does everyone who has a turbo use one and isn't that what PCV system does? is there a certain boost level where it becomes necessary?

thanks for the opinions, all you turbo guys let me know! :thumb:
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By teal_dx
- Fri Jul 24, 2009 5:57 pm #133148 when your engine is stock or NA and operates with a vacuum, it is not needed. but when you have positive pressure from forcing air into it, the stock pvc system no longer can work as it was designed to. Having the system sealed will no longer draw pressure from the crankcase and valve cover. The easiest thing for you to do is get a vented catch can with 2 nipples. Run one to the valve cover. Run the other to the rubber vacuum line that comes off the black box on the back of your block.
That applies to D series, B series have a different setup on the back of the block than D's do.
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By BLaCkSiLo
- Fri Jul 24, 2009 6:02 pm #133152 thanks man, i do have a z6, same as you? but can you use the stock breather valve on the cover where it goes to the intake tube in N/A mode?

and how do you tap into that box on the back of the block? what about those people who just have two lines running from the valve cover? does that vent it adquately?

also....is it important that i do that soon?
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By teal_dx
- Fri Jul 24, 2009 6:09 pm #133160 if you use the stock tube that goes into the intake to connect to your valve cover, then you will be forcing pressure into it when in boost - very bad. You want to keep that separated. So run the VC line to something that will not have positive pressure - the catch can.

The black box already has a tube coming out of it that goes to the intake manifold with a check valve in the tube.

Instead of running the tube to the intake manifold - which will now have positive pressure instead of a vacuum as it did in NA mode, get a longer tube and run it to the catch can.

People with 2 lines have better ventilation, but it is usually done on B series. D series pushing over 300 whp boosted I have seen it on before. But for your average kit, one line should be good.

Also don't use tiny vacuum lines in your setup... I think at least 1/2" would be good. These lines will have oil & blow by in them, so anything too small could get plugged up.

another good read although not anything you need to do: http://civic-eg.com/viewtopic.php?t=733
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