oil smoke after boosting.

[gauge_half_inch]

Maybe you turbo guys can give an idea where else to go with this issue. For starters I have a 92 sohc b6 with custom manifold and a DSM t25 turbo. I installed the turbo used with aprox, 70k on it. No shaft play to speak of other than typical oil clearance. Ran it hard for about a month and it slowly started smoking on decel after hitting boost. I assumed it was my catch can getting pressueized and blowing oil vapor back into the intake. So I installed a check valve. No change. Next I rebuilt the turbo, first time boosting, same thing. So then I bought a "360 staggered type" exhaust side seal. No change. I installed a oil restrictor banjo for the oil feed, it made it marginally better, then I changed the drain tube size to a larger hose. Again marginally better, but now only smokes after it gets warmed up to operating temp. Anyone have any other ideas?

[91mcnasty]

Little bigger restrictor?

Edit: technically I think it would be a smaller restrictor to reduce pressure.

[rollertoaster]

A general rule of thumb for restrictors is .060" for journal bearing, and .030" for ball bearing units.


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[M3NTAL]

I was going to say oil restrictor as well

Check your piping for oil, maybe just built up in there?

What color smoke is it

[gauge_half_inch]

The smoke is definately light blue. I can clean out the intercooler, but the piping didst have ay spots to trap it.

[nitrofarm]

Maybe its not the turbo?

Intake valve seals? Vaccum is highest on Decel...

[gauge_half_inch]

It did smoke a little while boosting. The valve seals were replaced about 30k ago.

[M3NTAL]

what turbo did you end up going with? how was the spool time?

[gauge_half_inch]

Dsm t25. I rebuilt it, still smoked, installed a -10 AN drain line and it stopped smoking. Atleast till the #4 rings went. Lol now I'm in the process of rebuilding the bottom end. While it held it was full 14lbs at 2900.