Is this PCV valve and catch can setup properly?
Last edited by Justin93; Oct 7, 2008 at 01:45 PM.
Trending Topics
The Best V8 Stories One Small Block at Time
check these pics out of my setup! Same ls6 valley cover
P.S. that silver thing you see on the top line is a Aftermarket PCV Valve as i was too cheap to pay $60 for the ls6 pcv line!
http://i341.photobucket.com/albums/o...FRONTOFPCV.jpg
top View
http://i341.photobucket.com/albums/o...OFCATCHCAN.jpg
You have to tell us whether or not you are using valve cover breathers in order to receive the correct answer.
-If no breathers, then the LS6 valley nipple goes to the bottom catch can line w/ the PCV valve mounted in that same bottom line. The PCV valve should open in the direction of the can. The top of the can then must run to each valve cover & the intake. There are many ways to do this. As long as they are connected, it is correct. (Do Not plug the valve covers & then only run the top of the can to the intake). Although, it will work, there will be no cleansing airflow through the valves.
If you have breathers, then just run the bottom line from the LS6 nipple w/ the PCV installed as stated above & then just vent the top of the catch can to atmosphere. (Do Not connect the top line to the intake & valve covers if you are using breathers). This will allow un-measured air to enter that will result in a lean condition. This will max out your STFT's & eventually your LTFT's leaving no safety net to correct for other lean conditions that may occur.
Before the "I did it like that withouta problem" crowd jumps in; chadnol10 asked for the correct way. The correct way(s) are noted.
ANYBODY HAVE A PICTURE OF THIS SETUP????????????
Is that correct or no?
http://www.ls1.com/forums/showthread.php?t=81389
My point about mounting the PCV valve in the bottom was that mounting to the bottom makes for easy venting @ the top of the can. If you want to mount it in the top, it's OK. Just position it so that the PCV opens toward the intake.
As for connecting a catch can directly to the intake & the LS6 valley cover while using breathers: The intake will suck air through the breathers & send it to the combustion chamber. This un-measured air is added to the measured (MAF) air & creates a lean condition. The O2's indicate to the PCM that the mix is lean & the PCM reacts by increasing your fuel trims. As mentioned in my previous post, this eliminates your safety net for reacting to lean conditions.
I use breathers as well. Difference being that my LS6 valley cover runs to a catch can through a PCV valve. The catch can is then vented to atmosphere.
My comments are not related to the operation of a catch can & are soley made regarding routing of the PCV system. I also clarified that the PCV valve can be mounted in either the top or the bottom, as long as, it opens toward the intake. My catch can is an empty Monster drink can. This is why I stay away from commenting about the operation of varying catch cans. So, if the manufacturer of your catch can states in the top & out the bottom..... Again, my comments are related to the PCV routing itself. For this reason, the PCV doesn't care where it enters the can. Your install looks good to me.
Important things:
1) LS6 valley cover, no valve cover air breathers
Routing is from LS6 valley cover nipple to the can, then to the intake. Also, must connect both valve covers to the intake in some manner.
2) LS6 valley cover, with valve cover air breathers
Routing is from LS6 valley cover nipple to the can, then vent the can to atmosphere. Do not connect the valve covers to the intake.
3) LS1 type PCV, no valve cover breathers
Single PCV line (after Y connection) to can then to intake.
Top or bottom of can makes no difference to me. Just do as the manufacturer states. PCV toward intake.
Hope this helps.
PS: I have logged STFT's while using valve cover breathers & connecting the LS6 valley cover to the intake. The log showed maxed STFT's. After removing the connection to the intake, the STFT's returned to normal.
"SARGE" is very experienced & has done one of a few things when he connected his catch can to the intake.
1) He has a speed density tune that was not mentioned
2) He re-scaled his MAF table to compensate for the vacuum leak created by allowing un-measured air to enter the engine.
3) Forgot to mention the potential problem this creates for guys whom do not tune.
Again, connecting the valley cover to the intake without re-scaling the MAF or using a SD tune, severely hinders the PCM's ability to react to lean conditions.
Last edited by Justin93; Oct 7, 2008 at 08:42 PM.
What if you have the newer PCV valve (it is an small orifice that is always open apposed to the old design) does it really matter what direction it is.
I know the LS2 is a different animal but after looking at my friends 2007 vette the hose goes strait from the valley cover to the intake with no PCV valve. Any input on this setup?

