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Im contemplating eliminating the the PCV valves from my newer stock cam covers . on my newer single turbo build.
Im thinking about just running some cheap braided lines to a breather or catch can or to the air intake.
I have seen this done on other cars and i did have this done on my other cam covers but im wondering what are the the pros and cons (if any )when doing this as i did not run this to long like this since i had to take the car in for some work but the thought just now came to my mind :scratch: on my new build.

I know the function of the stock pcv valve is to reduce HC emission's by having the crankcase route the HC through the PCV valve to the air intake for combustion in the cylinders but since im single now i dont think HC emissions will matter much.

anyways if you have any links to this info or any input please feel free to post and school(INFORM) me :)

-Al
 

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Discussion Starter #3

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SupraForums Manufacturer/Tuner
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Remove the PCV valve..... run two hoses to your catch can.... then either put a filter on the can, or run another hose from the can to the air inlet pipe of the turbo. The can will catch some of the oil vapor..... but some will get inhaled by the turbo. If you choose to just run a catch can with a filter...... your air intake pipes will stay clean but expect a bit of vapor or oil moisture to form near the catch can......



You made the same post in like 5 sections..... I thought that was a no no?
 

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1400rwhp/8 Sec Club
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The more ventalation the better.... I would drill and tap the holes and run new stainless lines to a catch can with a breather filter.
 

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Racing is Life.
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lol me too
 

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Ranger, The answer depends on your choice of engine management.
Fact: You need to vent any positive crankcase pressure off regardless of what you do. That being said, the oem ecu maps are designed to be used with a properly operating pcv valve and would need it routed back thru the intake. If you are going with an AEM, Map ECU, or other ecu tuning device, then you could probably tune around this and eliminate the pcv valve and run an open vent hose. But IMO, the pcv valve is so simple and inexpensive that you may as well use it. If you are going with an AEM or similar, it's up to you if you want to route it back into the intake. Going back thru the intake will yield you cleaner emissions (if you care).

I'm away from my car, but I believe there are equilization tubes between the two valve covers so there is only one hose going back to the stock intake. You can keep these in place and continue to only vent the one side, or remove them and vent both thru your catch can. Either way will accomplish the venting of any positive pressure. It's just two hoses vs. one.

More importantly, DO USE A PROPER CATCH CAN to condense oil vapor and prevent it from either making a mess in your engine compartment (if you choose to vent to atmosphere), or making it's way back into the intake (if you route back thru intake). Not all catch cans are created equal. Remember that the oil is in vapor form, so "most" of it can make it's way thru a K&N breather or even a basic catch can. The catch can would ideally have a labyrinth design and a lot of surface area to cool and condense the oil vapor into a liquid form and maximize how much it collects. The gas pressure will still find it's way from the high pressure area to the low pressure area. Just because a catch can is shiny and has a well known logo on it doesn't mean it works worth a sh*t. Spend a little time doing your homework on the right catch can, and you'll thank yourself later.

Here's a little cut/paste from Advance Auto parts website on the effects of an improperly working pcv valve with stock ecu maps:

"If the PCV valve is stuck open at engine idle, too great a quantity of spent gases are let through. Rough engine idling and stalling can be the result. If the PCV is stuck closed, pressure inside the crankcase can build up and the gases can force engine oil up through the breather and air filter causing excessive oil consumption and a fouled intake system. The good news is that replacing the PCV valve is both easy and relatively inexpensive."

I Hope this helps you out. Sorry for the long post.
 

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Discussion Starter #10
Sound Performance said:
Remove the PCV valve..... run two hoses to your catch can.... then either put a filter on the can, or run another hose from the can to the air inlet pipe of the turbo. The can will catch some of the oil vapor..... but some will get inhaled by the turbo. If you choose to just run a catch can with a filter...... your air intake pipes will stay clean but expect a bit of vapor or oil moisture to form near the catch can......



You made the same post in like 5 sections..... I thought that was a no no?

thxs for the info ..yes i did make the post in 5 places but i figured ill take all the info and make it into one on that other thread ;)
 
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or hook them up to exhaust scanvengers but then you'd have to weld the valves into your downpipe.
 

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Discussion Starter #12 (Edited)
Bruneti said:
Ranger, The answer depends on your choice of engine management.
Fact: You need to vent any positive crankcase pressure off regardless of what you do. That being said, the oem ecu maps are designed to be used with a properly operating pcv valve and would need it routed back thru the intake. If you are going with an AEM, Map ECU, or other ecu tuning device, then you could probably tune around this and eliminate the pcv valve and run an open vent hose. But IMO, the pcv valve is so simple and inexpensive that you may as well use it. If you are going with an AEM or similar, it's up to you if you want to route it back into the intake. Going back thru the intake will yield you cleaner emissions (if you care).

I'm away from my car, but I believe there are equilization tubes between the two valve covers so there is only one hose going back to the stock intake. You can keep these in place and continue to only vent the one side, or remove them and vent both thru your catch can. Either way will accomplish the venting of any positive pressure. It's just two hoses vs. one.

More importantly, DO USE A PROPER CATCH CAN to condense oil vapor and prevent it from either making a mess in your engine compartment (if you choose to vent to atmosphere), or making it's way back into the intake (if you route back thru intake). Not all catch cans are created equal. Remember that the oil is in vapor form, so "most" of it can make it's way thru a K&N breather or even a basic catch can. The catch can would ideally have a labyrinth design and a lot of surface area to cool and condense the oil vapor into a liquid form and maximize how much it collects. The gas pressure will still find it's way from the high pressure area to the low pressure area. Just because a catch can is shiny and has a well known logo on it doesn't mean it works worth a sh*t. Spend a little time doing your homework on the right catch can, and you'll thank yourself later.

Here's a little cut/paste from Advance Auto parts website on the effects of an improperly working pcv valve with stock ecu maps:

"If the PCV valve is stuck open at engine idle, too great a quantity of spent gases are let through. Rough engine idling and stalling can be the result. If the PCV is stuck closed, pressure inside the crankcase can build up and the gases can force engine oil up through the breather and air filter causing excessive oil consumption and a fouled intake system. The good news is that replacing the PCV valve is both easy and relatively inexpensive."

I Hope this helps you out. Sorry for the long post.

well i am using AEM ECU so i guess i need to start learning more about this thing :faint: well thanks for the info and all,oh and yes its a long post but very very informative and helpfull im sure to many will agree.

thanks all
- AL
 

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Bruneti said:
Just because a catch can is shiny and has a well known logo on it doesn't mean it works worth a sh*t. Spend a little time doing your homework on the right catch can, and you'll thank yourself later.
So what is the right catch can then? Please give us some options with stock ecu and AEMs. There are ebay ones for $20 and some name brands for $130...???
Thanks
 

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Running low boost on Na-t. 6psi. Would you need to use a catch can and reroute it back to the intake? Or could you get away with just a breather filter?
 

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Taimur said:
So what is the right catch can then? Please give us some options with stock ecu and AEMs. There are ebay ones for $20 and some name brands for $130...???
Thanks
id say go with the one that has atleast 10AN opening. other then that i cant see why anyone would pay 130 for a can. i guess some of the better ones have filters in them to stop the vapers from blowing by. thats the only reason to pay more for one.
 

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supradup said:
or hook them up to exhaust scanvengers but then you'd have to weld the valves into your downpipe.
Any more info on this?
 

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Discussion Starter #19

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With large Diesels Cat 3516 (one cylinder is close to 2 liters of volume, 16 cylinders total) I had a problem with running the crankcase breather directly to the intake. We ended up with a lot of oily goo built up on turbo compressor after 1000hrs of run time. This slowed compressor down and gave us less boost. Normal boost at load was 22 psi. What we ended up doing was putting on a coalesing filter that separated the oil mist form the gases, Worked great
So this of course would apply to these smaller engines. Catch tank with baffles, yes! Just some way to get rid of mist so it doesnt build up on compressor or in piping.
:bigthumb:
 
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