I currently have my oil drain feeding into the oil pan below the oil level. What are the chances of that being a big enough problem to cause it to burn oil?

 

I have no first hand experience, but the theory I've always heard is that being below the oil level will back oil up into the turbo (or not let it drain enough) which causes oil to slop over the "seals" (and think piston ring rather than rear main when talking about turbo seals) into the compressor and turbine.

If your compressor tubes were dry and you were not drinking oil before, it might be ok, but the "conventional wisdom" side of me would say to move the bung.

 

It will drain much better if the return line is above the oil level.

 

That may be the issue then. I know Rex loosened up my bearing tolerances a little bit and I think he did something to the oil pump spring also. I also went from 20/50 oil to straight 40 weight. Maybe the combination of those things is leading to too much flow through the oil feed line?

Sounds like I need to move the drain location.

 

If the drain is physically in the pan lower than the oil level, then the oil trying to drain out of the drain tube will have resistance due to the oil in the pan pushing back. It will actually work it's way into and possibly up the drain tube until it reaches the same height as the oil level in the pan. Under acceleration it may even go higher.

The oil leaving the turbo now needs to push against this restriction, and it can't do so within only roughly 18" of height. So now the oil backs up and it's the oil feed line pushing the oil down through the tube. In doing so it also blows it out the seal. It doesn't take much to do it either. Turn off an STS pump for a second and you'll see almost instant smoke. I'm now wondering if your old engine was smoking or if it was due to the turbo drain being too low?

 

My old engine was smoking and consuming 2qts/1000 miles before I ever installed the turbo. Adding the turbo probably compounded the problem, but I know there was a problem with the engine itself.

 

 

You definetly need to move the drain before you blow out the seals in the turbo.

 

I'm in the process of getting a new oil pan, I will move the drain as soon as it comes in.