69LT4

Started researching how to run the PCV system and an oil catch can and realized mine set-up is a little different. Though I believe there are people running the same set-up I am.
I have a trailblazer LS2 (port on driver's rear valve cover & port on passenger side front), corvette intake and the trailblazer DBW throttle body.
From what I have read the trailblazer TB doesn't have the fresh air port.
Curious on what others are doing with this combintation or what suggestions people have.
I would like to run a catch can as the car will be used on the road course.
Thanks,
Kevin

spacemanspif

iTrader: (5)

There must be a fresh air port some where for the port on the front of the passenger valve cover. It may connect to the intake hose instead of the TB but there should be 1 somewhere as its best to have filtered air entering your valve cover.

I THINK road racing lends itself to a dual can design where there is a can on the dirty side (rear of driver VC) and another on the clean side (front of passenger VC). Saikou Michi makes a nice can and has a dual can kit that works best with a LS6 valley tray but would work fine with yours. Mike Norris and RevXtreme are also favored cans. If you are going to go cheap, get a air oil separator for an air compressor from a hardware store before you blow your money on a ebay can that has nothing in it.

fieroguru

iTrader: (1)

On my engine LS4 with LS2 intake, DBW TB....

I tapped the silicone coupler between the MAF and TB for the clean (metered) air intake, then routed that hose to the valve cover with the oil fill (mine are flipped side to side, and the intake is mounted backwards). The other side goes to the catch can, then returns on the side of the LS2 intake.

69LT4

Thanks for the info guys.
Does it matter which valve cover port I use for fresh air? Meaning could I tap my air induction before TB and after MAF and run the line to the drivers rear port. Then use the passenger side port to go into a catch can, out of the catch can and into the intake.
If that doesn't work I guess my other option would be to do the valley cover conversion with the port up by the TB.
thanks,
Kevin

spacemanspif

iTrader: (5)

Drver's VC might have a little baffling for the PCV to try and not suck up so much oil. If there is that baffling and you don't want to empty your can so much, you could swap VCs or add baffling to the passenger "clean air" port.

If there is no baffling, then no, it shouldn't matter as long as 1 is connected to vacuum and the other is connected to a filtered air source.

69LT4

Some interesting info. Got this from another forum. Someone posted this from the intructions of their GM LS crate engine.

Positive Crankcase Ventilation System (PCV)
How the PVC system works:
A closed crankcase ventilation system should be used in order to provide a more complete scavenging of crankcase vapors. Filtered air
from the air induction system (air cleaner) duct is supplied to the crankcase, mixed with blow-by vapors, and passes through a crankcase
ventilation metering device before entering the intake manifold. The primary component in the positive crankcase ventilation (PCV) system
is the PCV flow metering orifice. Vacuum changes within the intake manifold result in flow variations of the blow-by vapors. If abnormal
operating conditions occur, the design of the PCV system permits excessive amounts of blow-by vapors to back flow through the crankcase
vent tube and into the engine induction system (air cleaner) to be consumed during normal combustion. This engine ventilation system
design minimizes oil consumption and significantly reduces the potential for oil ingestion during vehicle limit handling maneuvers.
How to set up your PVC system:
• There are three ports on the LSX long block that make up the PCV system. There are two foul side ports. Both of these ports should be
connected to the intake manifold and be exposed to vacuum at idle.
• The two ports are 1) Front port on the valley cover. 2) Left rear (driver) valve cover. These two silver tubes may look simple but, they should
not be modified. Both of the tubes have a small orifice within them that, is used in place of a PCV valve of early designs.
• There is one fresh air port which is on the front of the right (passenger) valve cover. Again this is a silver tube that faces forward on the valve
cover. This port should be connected to filtered clean air. This is typically within the engines air cleaner system or can be a separate air
filter if using a carburetor. If you are planning on an electronic fuel injections system that uses a mass air flow meter (MAF) then, the fresh
air to the PCV should be installed between the MAF and engine’s throttle body. The engine burns the air that enters the PCV system so,
if the fresh air port is prior to the MAF then, this air will enter the engine without being measured by the MAF.

Kevin