It's a journal bearing turbo - absolutely no requirement for an oil line restrictor unless your oil pressure is too high, they are regulated to 5bar anyway and rarely hit that when the oil is warm which is fine for a journal bearing turbocharger. Other people have run that same GT2052S without any problems in the past. A ball bearing turbocharger is different and requires a maximum of 40-45psi (3bar) maximum at full engine speed.
There's almost certainly another issue at play if the turbo is known good. Can you get a photo of the drain in place?
There's almost certainly another issue at play if the turbo is known good. Can you get a photo of the drain in place?
