Marcel Burkett

For a little while now I have been noticing oil smoke ( quite a bit sometimes) at the higher RPM's and have also been loosing level in the sump. I did some checks and realized that the oil had been passing through the turbos hot side , since the unit was still on warranty I removed it and had it redone (new bearings seals etc, free of charge) , now the same thing happens , when idling or under low load there is no smoke , if I get on it there is still no smoke until I let off the gas and get back on (slightly). The turbo builder says everything is good with the turbo and said maybe that the oil feed is too large , I have a 3/16" hole in my jet . The turbo supplier down Austratia said that that feed is good and shouldn't cause any problems , he also said that the turbo WILL leak at any oil pressure above 105psi ?? and advised me to switch from 20W/ 50 to something lighter like a 10W/40 , since the heavier oil may be sending pressures up at the higher revs , I cant say right now what the pressure goes to 'cause my oil pressure gauge (sender) is busted again .
I did some oiling mods (e shaft) and also polished my e shaft journals when I did my rebuild I am still using the factory oil pressure regulators , I spin to 9000rpm now , but would like to get up to 10,500 (and 25-28 psi boost )when I get my other problems ( slipping clutch AGAIN and fuel limit) sorted out . Any opinions and advise would be appreciated .
Thanks guys.

setzep

A. restrict the turbo a little bit more or B. make the return line bigger/better. Better yet C. Both

I have a .081" restrictor orifice on the inlet of my turbo. Thats a TON smaller than your .1875" orifice (3/16")

andericus mack

See the 'did i miss something' thread. In short, make
sure you have a good crankcase vent. The way it
is set up stock, you may be pressurizing crankcase
on high boost.

Marcel Burkett

My oil return is 3/4" (-12AN) and I have my crank case vent hooked up with three vent points , the catch tank is open to atmosphere , I am going to run it to the turbos suction soon.

Marcel Burkett

I made a mistake , the oil jet size is actually 3/32" , anyone know whats the recomended viscosity for our engines ?.

setzep

.093 still may be too big, maybe try a bit smaller one.

Mine will smoke a bit if I get off the throttle on the freeway ~4krpm for a long decel then get back into it. It will let out a little puff then it's all gone. BUT it will only do that if my oil temps ar a bit hot ~230 going into the engine. What is your oil temp when this happens?

RICE RACING

It should not smoke in any situation !

I run a high pressure oil system and have never needed to use a restrictor of any type.

Why my old turbo was worn out it smoked on a trailing throttle (perfect crank ventilation) it was a leak between the rear seal and turbine cartridge. It got rebuilt with a brand new wheel/shaft, centre cartridge and all new seals bearings etc, problem went away.

My oil pressure is 110psi and I use Mobil 1 5W-50 grade oil. Max revs 8800rpm.

If the problem gets worse as the turbo gets hotter then I feel its a housing to seal fit issue that is causing a leak hence the smoke ? especially if your sump venting is good.