LT1 POWR

Got a 383 with a single plain and a turbo. What do I need as far as crankcase ventilation?

RealQuick

Grab a catcan with two port (each valvecover can vent to it)

LT1 POWR

Do I need some sort of vacuum to pull air through the valve covers? What about a RX Performance Stage II PCV catch can. Its meant for boosted applications. Right now I've got enclosed breathers with a port to hook up a hose in the valve covers right now, but I don't have them hooked up to anything, just open to atmosphere. I'm putting new valve covers on and don't want to drill any unnecessary holes.

97WS6SCharged

Does the intake have provisions for a PCV valve already?

LT1 POWR

No provisions for anything. Should I run a vacuum line from the catch can to somewhere near the air filter so it pulls the crankcase vapor out?

Right now I have this, which has a spongy filter media in it.


Should I keep these and just run hoses to the catch can, or is there something better?

RealQuick

Positive crankcase pressure means pressure in the crankcase is higher than outside the crankcase (atmosphere)... which I am sure you know. If you run the lines from the valve covers to a 2 port catchcan (and the catchcan has a filter on it), then you should be fine.

If you want to be extra diligent, then buy an unvented catcan (3 ports) where the 3rd port has a line that runs to the cold side piping before the turbo. The sucking of the compressor will help draw from the catchcan... thus pulling from the crankcase.

LT1 POWR

I'll probably do something like this. I was looking at the RX performance Stage II catch can, which is meant for boosted gen 5 camaros. Anyone heard anything about these. I'm a little confused on the routing of the tubing.

mzgp5x

I have tried them all. I now run a crank driven vac pump. Also a centrifugal air receiver with an oil return circuit for vane lube. Super or turbo chaging usually results in to much ring blow-by. I pull a 1/3 athmosphere (about 5 psi vac) which seals the rings due to the ring pac pressure differential. I run this system in the street. I just converted to a single plane myself (World products motown w/ 4150 flange).
App... 97ss 383 D1 ATI with MM6 trans.
B.

LT1 POWR

Should I run a breather on one valve cover and a PCV breather on the other? This is what some people suggest. I was planning on running 2 of the PCV breathers with the nipples and having a catch can inline with a vacuum source sucking out the two valve covers, but I see that some people suggest I open breather and one PCV breather. Why is that?

97WS6SCharged

Basically fresh air comes into the clean can and is pulled into each valve cover. The clean can "should" never have oil in it. There is a check valve to keep air/vapor from flowing back to the turbo/blower inlet and into the intake manifold.

Dirty air is pulled out of the valley cover (PCV port on the LT1) and into the dirty can. This is where you should find any oil residue. The dirty air is either drawn into the intake manifold (front port on the LT1) directly or into the turbo/blower inlet during boost (the check valve should close to prevent pressurizing the dirty can).

You could techincally eliminate the clean can from the system to save money and reduce complexity by just running filters on the valve covers but you will probably find a little bit of oil on your valve covers from time to time.

97WS6SCharged

If you're doing a single can it would be something like this.



I wouldn't run the spongy thing personally. Just one more thing to get dirty and possibly cause problems later. Make sure you get a 3 port can with an internal mesh.

LT1 POWR

I have nowhere to hook up a line from the valley/intake since I'm using a single plane. So I was going to do a 2 port can. One line coming from the drivers side valve cover and the other to the pre turbo tubing for vacuum. I'll have a breather mounted in the passenger side valve cover. I know this isn't ideal, but it should work decent.

97WS6SCharged

You don't have any 3/8" vacuum ports on the intake? It will still work as you described with a 2 port can but I don't know how much vacuum the turbo will pull.

LT1 POWR

I have one port that feeds a vacuum manifold, which feeds about 6 vacuum/boost lines. I don't know if it would be a good idea to splice into this line cause it feeds, wastegate, boost referenced fuel regulator, BOV, Hobbs switch, and boost/vacuum gauge.

I figured the suck side of the turbo will always have some vacuum whereas the intake will pretty much only make vacuum at idle, very light throttle and deceleration.

97WS6SCharged

The turbo is going to pull air from the most free flowing spot possible which should be the filter so I wouldn't expect much vacuum from that.

Are you running an elbow on top of the single plain? If so you could always tap that behind the throttle body for an additional vacuum port.