I've been battling the idle smoking problem for quite awhile. I've finally noticed a pattern to the oil burning/smoking. It's always happened at idle only, and it only happens some of the time. I finally realized that like clockwork, any time my EGT's dip below 800 it will start smoking pretty good. If I brake stall the engine up and bring the EGT's up over 800 it goes away. I can then let it sit and idle again, and it will not smoke at all until the gauge dips below 800 again. After that, here comes the burning oil smoke again.

Turbo is a Precision PT76GTS.

I'm running a -4 feed line with a .054" nitrous jet for a restrictor, and a -10 drain line with no kinks or uphill runs. It drains into the pan above oil level.

Anyone have any ideas?

 

I know there's a lot of turbo guys over here....come on guys....

 

Oil out the turbos if the shaft play is normal is normally stuff like you said. Too much oil pressure more common on Ball bearing turbos. Blockage in the oil return or defective /dead scavenger pump. Excessive crankcase pressure again usually a block vent or catch can hose or something similar. And of course oil out the back can be blown engine. That said having oil from the other causes does not normally kill the turbo.
I have experienced the problem a few times on my garett and mits turbos in my dsms and after the problem was fixed the oil quit coming out. I did think it was engine each time.
I have not heard of low or high egt causing it. Check oil pressure, maybe you need a smaller restrictor. Check crankcase venting and check oil return for restriction.
If all else fails check shaft play in the turbo. Is this a turbonetics turbo or garett? I have seen many many turbonetics seal problems on the dsm board. Buddy went thru numerous ones. I stick to garett or mitsubishi myself.

 

I checked the shaft play a few months ago and it was normal. Oil pressure at idle hot is about 45 psi. Drain is gravity - no scavenge pump. I have changed out the return line and re-routed it so it does not have any blockages or tight bends. Crankcase is a hybrid PCV/breather system, so there should not be any excessive pressure building up inside the crankcase. Breather on the driver's side valve cover, line from LS6 valley cover to check valve to intake manifold, and line from passenger valve cover to fitting just before the turbo.

Not sure on the brand of turbo....checked Precision's website and it looks like a Garrett turbo, but I'm not sure how to check the turbo itself to see the brand.

I'm thinking of trying to swap turbos for a couple days to see if the problem remains or disappears. That is probably going to be my best bet to figure out what's going on I guess.