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Need some help determining what to do with the PCV system on my build. The more I try and read online, the more confused I become. So here is what I have:
06 LQ4 N/A
LS6 intake
LS6 valley cover
Plans later down the road include cam, heads and a tune. No forced air for now. Still running the truck DBW TB and MAF in the air intake.
1) Do I really need a catch can?
2) If so...what are the proper connections?
3) If not, how do I need to run the PCV system?
I feel like the more I look into this, the dumber I get. Help me to stop over thinking it.
Here is a picture of how to connect the ls6 pvc normally. Since your vacuum port is on the opposite side of the intake to connect it like this is going to look pretty wonkey under the hood, but you might be able to make it look somewhat appealing with a catch can mounted up by the radiator somewhere and running lines to either side of the motor. I think I would leave the valve covers capped and go that route. I cant see if #4 is actually a port or not, if you can connect to it then you should be able to mimic this picture and leave 1,2,3 and 6 capped and put a breather on the oil fill
Last edited by Mart00SS; Dec 14, 2017 at 07:39 PM.
Adjust that AN fitting so you have room to put a hose on it and mimic the picture above to that port. It will pull a vacuum on the valley as designed. Then block of all other ports as mentioned and put a breather in the oil fill hole in your valve cover to allow fresh air to enter.
I you are going to use a MAF you need to pull fresh air from the throttle body air intake after the MAF and before the throttle blade. Pulling fresh air from a breather in the valve cover will let unmetered air into the intake and mess up the fuel mixture and possibly the idle. As in this picture note the line from the throttle body to the right valve cover is drawing air from in front of the throttle blade and after the MAF. It’s hard to tell in your pics if your throttle body has this port, but any port that is drawing air from the air intake in front of the throttle blade and after the MAF should work. Also most newer LS6 valley covers have a PCV valve built into them, so there is no need to use a PCV valve in the hose from the valley cover to the intake.
GM sells that hose with the u bend in it if you’re not going to use a catch can get this hose, it makes for a clean install.
If you are going to use a catch can put it in the line from the valley cover to the intake.
I you are going to use a MAF you need to pull fresh air from the throttle body air intake after the MAF and before the throttle blade. Pulling fresh air from a breather in the valve cover will let unmetered air into the intake and mess up the fuel mixture and possibly the idle. As in this picture note the line from the throttle body to the right valve cover is drawing air from in front of the throttle blade and after the MAF. It’s hard to tell in your pics if your throttle body has this port, but any port that is drawing air from the air intake in front of the throttle blade and after the MAF should work. Also most newer LS6 valley covers have a PCV valve built into them, so there is no need to use a PCV valve in the hose from the valley cover to the intake.
GM sells that hose with the u bend in it if you’re not going to use a catch can get this hose, it makes for a clean install.
If you are going to use a catch can put it in the line from the valley cover to the intake.
Damn youre right I didnt think about that, definitely need to follow these instructions if you run a maf.
Last edited by Mart00SS; Dec 15, 2017 at 10:14 PM.
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LQ4 w/ LS6 Intake PCV setup 
