Big Bu Bu

iTrader: (4)

It's been reported to me by other drivers that my LS6 CTS V will on occasion shoot smoke from the exhaust tracking out from slower sharper turns where I need to get hard on the gas. My car is a head and cam bolt on motor with a FAST intake and a 102 TB. The car reports good AFR throughout the power range and doesn't use alot of oil. Compression is good. Power is good. I perhaps thought that the headers may be leaking which can suck in air and lean out the 02 sensors which causes the ECM to dump fuel. I'm not sure that is the issue since I've torqued those up already. I do run an oil cooler and remote filter which requires me to add an additional 1.5 quarts. The tips on my Corsa exhaust are fairly sooty after the event. The smoke problem is not chronic on the track but rather intermittent. Anyone experience anything like this?

mitchntx

iTrader: (14)

My old LS1 street car used to do that.
Mild heads and cam, headers, ported TB ... tune.

http://www.youtube.com/watch?v=RdGrYXUs7C0

Mine was strictly tune related.

240dan

Sounds like oil getting into the intake. My LS6 does it too, a catch can for the breather and a PCV catch can are a good place to start if you plan on doing many track days. Check the intake side of your pcv for oil. I built my pcv catch can but there are a few companies producing them.

SIK02SS

iTrader: (11)

Yup, install a catch can. I recommend an ARE or Moroso. I have an ARE for sale if you want it..never opened and in packaging still.

Big Bu Bu

iTrader: (4)

That's it Mitch. That's what mine does. Just like the video.

Big Bu Bu

iTrader: (4)

You may be right Chris. I do have a catch can but when Katech did my bolt on motor, we changed out the throttle body and the old style can (78mm) I had didn't quite work. We came up with a work around, but I think it's not very effective. I never saw an ARE can. I may be interested.



Mike

mitchntx

iTrader: (14)

Also had an LS6 intake and PCV setup (machined the block) to fit.

Does it leave black residue on the bumper cover?
Mine certainly did.

I had it tuned by 3 different shops (2002-2004 timeframe) and it never went away.

It was fine under "normal" daily driving. I always wondered if it was mating the LS6 intake to the non LS6 heads (can't recall the casting) that cuased it.

Big Bu Bu

iTrader: (4)

So isn't vacuum highest when the throttle plate is closed / closing. My set up seems to only pull vacuum on open throttle since the hose is connected on the other side of the throttle plate. But then again maybe it is the tune.

SIK02SS

iTrader: (11)

What usually happens to cause it is either a few hard braking points followed by a straight away, or sustained high g mid rpm corners that go into a straight away section. This year at Autoclub Speedway I was going through the oval at about 140 exit around 150 to ~155 and in that time between exit and the few mph up, it was a descent smoke screen because of oil build up in the intake from the heads. I installed the catch can that weekend and it still happened, but dramatically decreased. This also happened to me at buttonwillow last year (no catch can) and did not happen this year, with catch can.

Looking at your picture, I don't think it's plumbed correctly. I'll try to snap a picture of mine later..it shouldn't go into the intake like that, needs to go into the PCV lines below/on the throttle body

240dan

Looks like it's plumbed as a vent which is ok but maybe think about re-plumbing it as a pcv (especially if you daily drive it too). The catch can will do the job either way as long as it has a baffle between the inlet and outlet.

SIK02SS

iTrader: (11)

forgot to get those pics for you:

Big Bu Bu

iTrader: (4)

It's in there somewhere

lubelizard

iTrader: (5)

I think the catch can is misrouted. Perhaps there's an oil buildup at the throttle body opening, and when you track out on throttle it drives the oil into the engine. I have the same catch can and the outlet hose is routed to just rear of the TB on the neck of the intake. Is there a dark buildup around the throttle blade? Dark spots on the headers near the ports/valve covers? I'll post a photo what I'm talking about.

Big Bu Bu

iTrader: (4)

Mine was originally routed like yours. My can was made to use with the 78mm TB. A new Mike Norris can was designed for the 90mm and 102. When I upgraded I wanted to keep the old can. The Katech guys routed it this way, but to be honest I never knew why.

lubelizard

iTrader: (5)

If you have nipples similar to SIK02s, route the catch can hoses the same way he has it, then the nipple from your intake elbow to where he has the TB to silver tube connector. That would simulate the LS2 setup.

SIK02SS

iTrader: (11)

The way mine is routed through the PCV system there is a slight relief in crank case pressure similar to how a dry-sump does..obviously just no where near as well lol

Big Bu Bu

iTrader: (4)

Thanks for the help guys. I have a hose from the valley cover nipple direct to the high vacuum intake manifold port. No PCV valve is required here because of the design of the valley cover nipple. The valve cover vent can't use the intake manifold as a vacuum source because it's already being used. So the intake tube was selected as a vacuum source for the catch can. So I'm wondering if this setup might allow unmetered air in or cause other issues. I've seen some cans where there are three ports. One for the valley cover hose, one for the valve cover hose, and one to the intake manifold for vacuum. I have an oil leak which is a pain in the *** to find and I'm wondering if it's a result of excessive crankcase pressure