The most common reason a 993 turbo smokes on startup is the turbochargers siphoning oil from the engine after shutoff.
Turbo oil drain pump.
The air bubbles may have to settle out of the oil before the pump will pump.
Even on systems that are able to gravity drain this is a possibility to avoid tapping the oil pan.
They are also suitable as turbo oil feed pumps where gravity drain is possible and are often used where a separate turbo oil supply is used which.
In this case the engine supplies the oil pressure and the pump simply returns the turbo oil to a point above the sump level.
2 5 8 billet machined custom hose barbs.
These pumps are suitable for remote turbo systems as oil scavenge pumps.
The return oil from the turbocharger may also contain air bubbles.
It may also be necessary to have an oil reservoir installed in the oil return prior to the pump.
Running the external pumps there is noise associated with this.
Rarely is the smoking at start up due to worn out turbochargers oil draining back into the turbochargers from the crankcase or worn valve guides stems seals.
The turbocharger can only drain from gravity there is nothing else that will force the oil out of the turbo back to the pan.
After researching i found this setrab banjo adapter m22 to an10.
If utilizing an oil return pump the pump should be mounted lower than the oil drain on the turbocharger.
I am doing a turbo conversion on my 79 sc i was looking for a way to drain the oil from the turbo back into the sump.
1 on 3 performance oil scavenge pump standard black pump not carbon like photographed.
It is supposed to be the lowest profile 90 degree on the market.
Cxracing electric oil scavenge pump for turbo oil feed perfect for bottom mount turbo applications that need to positively scavenge oil between engine and oil pan 12v dc 6 a amps 3 2l gpm.
So if you have the turbo 10 degrees on average from vertical on the feed it leaves the oil in the chra longer than it should be.