Vetal

iTrader: (3)

Finished my build recently and very soon noticed that after even little boosting, on deceleration cloud of smoke appears behind the car, so apparently TC78 is burning oil. I have 6mm feed line and 16mm drain line (but at very shallow angle). What is the problem? Maybe some restrictor is needed for TC78?

Bhogan909

iTrader: (6)

How do you know the smoke is coming from the turbo? Could be blowby in the engine. Putting boost to a motor brings small issues to the forefront. The turbo maight be causing the issue, but I doubt the turbo itself is what is smoking.

smokinHawk

iTrader: (48)

Probably the drain

Vetal

iTrader: (3)

because it smokes only on deceleration and only after boosting

Vetal

iTrader: (3)

it is 16mm, or 5/8" inner diameter, and it never goes horizontal or upwards...

mike13

iTrader: (27)

Could very easily be your PVC or breather system, oil gets blown into it under boost and under vaccum gets sucked into the engine. Usually under boost will you see smoke when a turbo is letting oil by.

black98ws6ta

iTrader: (77)

Can you make the drain not such "a very shallow angle"? I would resort to a restrictor as a last case solution..unless the motor has more then normal oil pressure.

98Z28CobraKiller

iTrader: (17)

What oil are you running? 5-30 smokes in mine. I run delvac 15-40 now and never any smoke.

Dean95z28

iTrader: (7)

You do not need a restrictor for those turbos. The restrictor is built in the brass fitting that comes on the turbo. What turbo kit are you using?

Vetal

iTrader: (3)

black98ws6ta: no, turbo sits low enough. pipe goes down about 1.5 inches and is 9 inches long. However when I read about drain pipes, it was said that such angle is OK with a drain line of such diameter

Cobrakiller, I run exactly 5W-30 Some cheapish one (MAG1)

Dean, this was just a TC78 turbo from Forced Inductions. But I don't remember seeing restrictor in the CHRA itself. It had some adapter with filter in it, but I also don't remember seeing any restrictor there...

mike13

iTrader: (27)

My suggestion is to run the car do a couple of pulls bring the car back and take off the turbo tubing like the elbow into the intake and see if there is oil in the tubes. Oil doesn't stay suspended so there should be signs of oil in the tubes.

Vetal

iTrader: (3)

Yes forgot to say... There IS oil in charge pipe, much more than I would expect

98Z28CobraKiller

iTrader: (17)

Drain oil. Get some Mobil Delvac 15-40 diesel oil and see what happens.

98Z28CobraKiller

iTrader: (17)

If you are in a really cold climate, make sure to warm up the oil good before you do any reving. Specially with the heavier weight oil. I live in Florida. No winter here.

52172

iTrader: (2)

Make sure your motor is vented properly mine would do the same until I put a breather on my catch can and on a valve cover.

crashly

you have an air cleaner on the front then ??
yes ??

Johnv

Your return line should have been bigger(mine is 3/4 0r 20mm) especially if you don't have much fall.
also if you don't have adequit crancase ventilation under boost, crankcase pressure will prevent or restrict your turbo oil drainback.

Vetal

iTrader: (3)

Thanks for all replies. I'll try to answer all of them:
98Z28CobraKiller: are you serious about that diesel oil? what whould I know by doing this? yes I'm in cold climate and I always warmup fully before putting more than 2000rpm or more than 70% throttle

52172: how do I make sure it is vented?

Johnv: so 16mm ID is not enough for drain????

needaz28

iTrader: (15)

mine was doing the same thing. my turbo sits pretty low aswell, I decided I wasnt going to mess with it and bought a return pump. ($100) I have a -4 feed, a -10 off the turbo (about 6-7 in. long) then a -6 to pump and to the pan. havent seen smoke since.

mightyquickz28

iTrader: (8)

This has nothing to do with the Turbo. When decelerating with closed throttle, your engine is under tremendous vacuum. Traditionally, when an engine smokes on deceleration, it's pulling oil past the valve guides/seals, onto the back of the valves, into the combustion chambers and burning.
If it was smoking on acceleration then I'd say 'maybe' your drainback or piston rings. What color is the smoke? Classically....

Blue smoke = Oil burning
White smoke = Coolant burning
Black smoke = Too rich.