so while talking to percision at import vs domestics last year they say to run a 4an line

 

His oil feed wouldn't cause the smoking issue since it's actually smaller than the recommended size. The only other thing that can be happening is excess crankcase pressure or blockage in your drain. Sounds to me like your drain is routed properly, Is it a brand new hose? Oil can coke up in there and create a blockage if it's close to the manifold.

Do you use the factory PCV system? All this smoke could be an indication of serious blow-by. I've heard that a turbo abnormally smoking can be an indication of poor engine health.

 

I'm running a -12 return on my 8884. Boost Lab in Florida made 12 return setup for me and I believe they still offer it. The oil pan fitting was fab'd up too via a -12 an aluminum fitting welded directly to my upper oil pan. Long story short you will have to go the custom fab route.

 

I am not worried about the -3 even Precision said on the phone yesterday "it's obvious you have plenty of oil at the turbo so lets look elsewhere." I will concede they suggest a -4an. The return is no where near the manifold (log style makes running the return pretty easy) and the ID looks as good as when new.

Engine health is good. Origional motor 87000 miles, no noticable blowby, good/even compression. Now here is something interesting about the PCV and I am starting to think that is suspect. I have a catch can set-up that feeds back into the intake. I checked it yesterday and it was about 1/3-1/2 full of basically water, mixed with some oil vapor, basically what I would expect to see. It was no where near the level of the line that goes to the intake but still. Now yesterday I started it for a while with the intake pipe disconnected, something I don't normally do. The end of the PVC/breather line was just sitting there and sputtered a little bit of water out onto the block while it was running which was weird. That line obviousely had condensed vapor in it and I have a feeling it had enough water in it to act like a trap on a home plumbing system (sink, toilete, etc) I blew out the line before I measured how much water but if that was blocking the PVC I can easily see that causing higher than normal crankase pressure, leads to backing up the turbo, and we have smoke. While I had the intake disconnected it did not have a smoking problem and after I cleared the line and reconnected the intake pipe same thing no problems.

Sounds reasonable to me, I can test this by clamping that line and if it gets smokey I know that is it.

I was getting so focused on the drain I kind of forgot about the PCV system in all of this.

 

Im interested to hear what others say, I have a 6466 with a -10 and it is fine

 

Measure the drain width, plumb appropriately. I prefer a 12an drain, as thats what Boost Lab told me to run.

 

If you're still in the market for a -12 setup, OCD Works makes a turbo and block fitting that is really nice...

 

Sounds more like the turbo seals are going or are bad. Either that or the line is kinked somewhere…

 

If you need a -12 line that is already made, I have a 12" long -2 BMRS line with heat reflective sleeve already on it ready to go. I messed up and needed a -10, so I have an extra.

 

the -3/-10 should be perfect?
Are you sure it is not the turbo itself?

 

I have a similar problem with my car (not a Supra) ... I ordered a -12AN flange -- I think my current straight tube flange is "crooked" a bit (the hardline hose I think bends too fast towards the the return port, causing it to pressurize more .... like your thumb over a garden hose) -- you need to make sure your line is completely straight. Having said that, if your line is straight, it's probably caused by excessive crank case pressure -- I'm fully vented to atmosphere, and still have this issue (the oil can't get into the crank case due to too much pressure) ... I'm going to hook up an exhaust evac system -- that should help. The smoke is caused by the CHAR filling up with oil/pressure and coming through the piston seal on the exhaust side (usually after boost you see it -- at idle -- I guess you don't see it when driving) ... I think this is caused by ring gaps too small on the pistons and well, just too much pressure in there that can't get out of the head breathers ... could be dirty, could be a crooked line, could be the oil type (changing to different oil can help), or could be just way too much crank case pressure, and you need to vacuum it out.

 

Alright, had some time this afternoon to play around with it some more. To be clear when this started I was thinking turbo as well and I still have not eliminated that. I talked to the vendor who sold it to me (not helpfull at all) and then Precision and they at least talked me through it all. At that point I was planning on sending it in as a BAD turbo, keep in mind it has 0 miles on it. Reason I was thinking this way was I was and am sure my feed and return line are just fine. Reason to start this thread was to see how others are doing a -12 return line. Except for Boost Lab which I see did offer a -12 kit bot for $200 it was a little rich for my blood for a test. Suprabrian44 steered me back into looking at the PCV again. I have a catch can and it recirculates back into the intake, with as much vapor as I get in this I am thinking about routiing it somewhere else now. Anyway I think it is very possible that the line between the catch can and the intake pipe was filled with enough water to act as a plug.

In testing today I found that you can make a turbo start smoking in about 10 seconds if you pinch off the PCV line. You can also use a shop vac to be absolutely certain you are pulling a vacuum and evacuating the crankcase completely. Kind of cool actually. I am going to continue to play around with this as I still smell some oil but I am not sure if that is just some still burning off or what.

I am still interested if anyone has sourced a turbo and pan flange that works with something other than a 1/2 NPT threaded fitting other than Boost Lab and OCD? which I will look up. I also have to do some more reading about recirculated PCV systems.

 

Take the exhaust off the turbo... do you see any oil? I used a video scope on mine through the wideband bung to check -- no real oil there, which means it's getting a little oil at boost and then burning off at idle ... just to confirm, what color is the smoke? Mine is white (but it's not from coolant).

I'm sure someone has a diagram of the stock Supra PCV system ... generally, stock systems use the intake (creating a minor venturi effect) to vacuum out the crank case, but it's generally piped to push any blow-by back into the intake manifold to be burned off (for emissions). You can check the intake manifold for oil as well (not easily done of course).

Most street turbo cars run catch cans ... which basically jsut catch gunk when blown out, but if they're not hooked up to any vacuum -- they don't help much with crank case pressure. Air/Oil seperators generally keep the connect from the intake/inlet from the turbo, to create some vacuum into the can ... and the can then plugs into the heads and crank case (a closed system). This minor vacuum helps as well ... but you should generally close off the crank case breather and only plug in the heads.

A poor man's vacuum solution is an exhaust bung that creates the venturi effect to create a vacuum source (stronger as RPMs go up) with check valve -- sucking on the head breathers (closing off the crank case vent) ... this will create a vacuum on the rings to seal them better and suck extra pressure out of the crank case ...

Big race car setups use a belt-driven vacuum pump (with secondary electrical one) ...

The only catch is -- some people with similar setups don't smoke and others do -- so while the vacuum setups might help (and larger oil return), generally it means there is a problem somewhere with your build (ring gap too small, breathers plugged up, or worse).

Good luck.

 

Does it smoke out the exhaust immediately after a cold start? Or does it take a couple of seconds/minutes?

Does it throw smoke out the exhaust under boost?

Does it smoke even after driving it around for a while?