PCV valve question

[mitsuclipsegsx]

Do i just plug it or....

 

[TSiAWD666]

That's your pcv. It should connect to a line in your intake tract. Do you need it? I'm sure someone will answer but I don't know as I'm not really familiar with its function.

Edit: I was having a brain fart. It's for crankcase ventilation. It allows pressure to leave when there's vacuum in the intake, so you don't build excessive pressure in the crank case.

 

[absolute_DSM]

That is your PCV valve.

You need connect that to the intake manifold. That way it closes under boost and vacuum will open it. No "buts" about it.

 

[hopwoodp]

Read this. It explains how to run the positive crank case ventilation valve if you don't want to run it from a line from the intake manifold.

http://www.roadraceengineering.com/instructions/catchcaninstructions.htm

 

[turbosax2]

While you're at it, check to make sure the pcv is working ok and if not replace it with an OEM one.

 

[Flash]

One thing to note is the PCV valve is a one way valve. Like RRE pointed out- when you are under boost the PCV valve stays closed since it is a one way valve. When it is closed crankcase pressure will begin to build; which is why extended periods of boost is harmful.
So get a crankcase ventilation system (like the link above) and you will be much safer for extended boost situations.

 

[Flash]

While you're at it, check to make sure the pcv is working ok and if not replace it with an OEM one.

If he is going to get a crankcase ventilation system why check the PCV valve? The ventilation will totally eliminate the PCV valve.

And I believe to check if a PCV valve is still good you shake it. If it rattles then it is still good.

 

[absolute_DSM]

Educate.

Effects of routing your PCV to a catch can.
http://www.dsmtuners.com/forums/showthread.php?t=242123&highlight=PCV

This is a very debated topic on this forum. I suggest searching "PCV" and drawing your own conclusion.

 

[turbosax2]

If he is going to get a crankcase ventilation system why check the PCV valve? The ventilation will totally eliminate the PCV valve.

And I believe to check if a PCV valve is still good you shake it. If it rattles then it is still good.

Sorry, I meant to check to make sure if its ok if he decides to keep it.

 

[Flash]

Sorry, I meant to check to make sure if its ok if he decides to keep it.

It's ok, I forgive you.

I read a about half the posts in the link above. What I never saw discussed was when your boosting for extended periods of time crankcase oil can get past the rings and cause detonation and fry rings, crack pistons, etc... Correct? For daily driving you will not be boosting for extended periods of time like around a road course for example; therefore you could benefit from keeping the PCV valve.

 

[Black_Bullet]

While you're at it, check to make sure the pcv is working ok and if not replace it with an OEM one.

Remember though, oem pcv valves tend to leak as they arent very capable of dealing with increased boost pressures... I find it worse for it to leak and be sending positive pressure into your crank case than simply not running a pcv valve at all...
I dont run a pcv valve and yea its not good for idle ventallation but I still have the valve cover breather line going to the intake and I plan to tap the head for a second v/c breather port to run to the other intake arm port and get a sbr or greddy catch can or something. My pcv has a hollow threading in it with a hose that just hangs under the car.

 

[turbosax2]

Remember though, oem pcv valves tend to leak as they arent very capable of dealing with increased boost pressures... I find it worse for it to leak and be sending positive pressure into your crank case than simply not running a pcv valve at all...
I dont run a pcv valve and yea its not good for idle ventallation but I still have the valve cover breather line going to the intake and I plan to tap the head for a second v/c breather port to run to the other intake arm port and get a sbr or greddy catch can or something. My pcv has a hollow threading in it with a hose that just hangs under the car.

Ok, here's my thoughts on this subject.

http://www.dsmtuners.com/forums/showthread.php?t=229338
http://www.dsmtuners.com/forums/showthread.php?t=254437

Those links are interesting to read and have bunches of good info in them. Basically, what I got out of them is to keep the pcv and valve cover breather line (going to intake pipe) like they are, in stock configuration. However, add a catch can inline with both (I chose to use a Husky filter) and also add a check valve in the pcv line (between the catch can and intake manifold). The reason for the check valve is because, in general, pcv valves are horrible. I have read that Autozone pcv valves are not meant for boost and this is why I recommended an OEM pcv, crappy as it may be. Either way, the check valve is a solution for a crappy pcv valve.

Now, I assume the OP's car is street driven, seeing vacuum a lot of the time (please let me know if my assumption is wrong).

A quote from RRE's website:

An option for cars that never see use on the streets is to disable the PCV valve. Under normal operation the PCV valve allows crankcase air to be drawn into the intake manifold when you have vacuum in the manifold. Once you make boost pressure, the PCV valve closes and the only ventilation the crankcase gets is thru the small hose that was running to the turbo inlet.

They suggest to only eliminate the pcv if the car is track only (constantly seeing lots of boost).

To the OP, like absolute_DSM said, this is a very debated topic and you need to research this on the forums so you can make your own decision. My .02, keep the pcv in stock configuration but add an inline catch can and check valve.

 

[alex99gst]

I had mine routed all crazy for a while until I did some reading and switched back to the stock setup. It is common knowledge that the stock pcv valve will leak under pressure. I grabbed a second OEM pcv valve from the junkyard and now run 2 pcv valves inline. I figure that whatever boost leaks past the first one the second will be able to help it hold off more from entering the valve cover.