that would drive me nuts! if it were me i would allready have installed a crank case vacuum pump and made sure that the return was above oil leven in the oil pan...

if all else fails.. you can always add an electric scavenging pump like the guys running reat mount turbos do.. that will solve it for sure

thought of that too, but it's just one more thing to fail (with my luck......... :willy: ). The drain is above the oil level, I've run the engine with the line disconnected at the pan, and draining into a bucket, and nothing comes out of the pan.

Jody

How about a fuel preasure regulator. It may not be a good permanant fix but it might work for test purposes.

IMO major changes are not called for yet. You need to pin point exactly what the problem is first! There are to many variables right now. IMO this needs more testing and trouble shooting to narrow the focus. It still may be that turbo and no amount of rework or bandaids is going to fix that. IMO you have to eliminate or confirm the TURBO it self.

When I hit this type of wall an little time off has turned my light bulb on with the solution or a test and normally comes out of thin air for me.

it's either the turbo itself or drain line angle/fitting. I'm eliminating the turbo only because the likelihood of having it bad even after inspection and repair is low. Doesn't mean it's not still an issue, but I'm playing the odds here.

The drain line is fine at and entering the pan, as disconnecting it there doesn't fix it. The fittings and line size are identical for both sides, but I am noticing that the angle of the oil in/out of the turbo is much more vertical on the problem side; the passenger side is clocked further towards 45 degrees to clear the turbo mount pad (not literally 45 degrees, but just to give an idea). This makes the passenger side more downhill out of the turbo drain than the drivers side, noticeably so. The drivers side being almost vertical has the drain fitting putting the oil more horizontal, or at least much more so than the passenger side. This is the direction I'm heading now.

Unfortunately, that requires the turbo to be removed which is a large job; can't reach all the clocking bolts with it installed.

Jody

If when you pinch off the lines the smoke goes away, then the seals in your turbo are bad. 90's 45's and all that is moot, as there should be no oil getting into the exhaust side of the turbo. I've seen people toast them on start up because a lack of oil on start up.

Bad turbo oil seals act like bad vavle stem seals. They'll smoke like crazy at idle and clear out a bit on throttle.

they just replaced the seals on this turbo. The initial one showed "wear" but not exactly sure what that means.

The seal is more like a piston ring than the normal seal like on a guide as you know. They cannot handle puddles of oil against them, which is why if a return pump fails on under-car turbos they immediately smoke like crazy (been there, done that).

So you are correct in that it could be a second bad seal, but that is not all it can be. If the oil is struggling to get out of the turbo and puddling up against the seal, even a perfect seal will do the same thing.

Since it's not an immediate thing, but takes a certain amount of running before it smokes, and again 2-3 minutes after pinching the oil off and then returning oil to the turbo before it smokes, it seems like the oil slowly is building up, backing up, and then finally reaches the seal, overwhelms it, and smokes. I'm in the process of changing the angle of the outlet to match the other side; we'll see if that fixes it.

This is a small amount of oil; the pipe isn't wet at all, just enough , a few drops to make some smoke.

Jody

I believe someone asked previously, but what oil pressure are you getting to the turbo? Is the pressure to high?

What is your source for the oil feed?

I have never seen a return create such a buildup though. Do you think that because of a restriction in the return side that the feed side is creating a pressure to high in the center section. Is that what your thinking?

Hope I am not being a pain, just a curious bystander here.

I have 35 psi hot at idle. Both turbos feed off the same line, which is tee'd in the center to feed them. My latest thought, for what it's worth, is that the 90 degree fitting on the outlet (required due to frame clearance issues) is too upright of an angle. In other words the fitting comes almost straight down off the turbo and then is almost horizontal at the end of the bend. The other side has the center section clocked differently so that it's app. a 45 degree angle off the turbo to the outside of the car, then turns 90 degrees to be 45 degrees down again towards the oil pan. This is the only difference in the two sides, identical fittings, line sizes, etc. My thought is that this could be the difference in flow backing up, because when I ran the car with the drain line running into the bucket I was surprised how much flow comes out of that line, considering it's reduced to only a .035" hole on the inlet fitting.

The next step will be to find an inline regulator of some sort to reduce the oil pressure at the turbo. I'm told the ball bearing turbos only need 5-9 psi at the turbo, and I'm way past that.
Jody

maybe the seals are already toast... but they shouldnt be..

Jody if it were me id start playing with the drain size of the pan I still think that has somehting todo with the smoke but thats me.