Yes. This turns very interesting. Maybe all these work combined together?
How about this thoughts:
If the mystery pipe have an one way valve inside turbo core that only operates on direction of vacuum? (on idling there are vacuum on near engine where pipe connects. Not atmospheric. Piping, intercooler etc all cause restrictions and naturally weight of the air itself on pumping suction cycles of engine. I think it must have someking of valve or atleast not direct access for oil circulation because its no sense to let boost in to that pipe against of an oil pressure. It will push oil away from turbo core: Very rapid, spectafull but unwished death for bearings. To having an actual air flow thru it, an replacement air source from the intake system after MAF is needed. (all air for the engine need to be measured for correct mixture) Only such valves seems to be either Turbo divider (vacuum operated) or Boost pressure valve (solenoid). By either of these the airflow can be controlled for that 3min point.
Thinking how to test this easyly on engine on place of a car:
- Closing the rubber vacuum pipe for the turbo divider valve on next to actuator on top right of the engine.
- Try to reach turbo boost solenoid connector and remove it. (need to remove air hose for access)
And then one by one listen if the tone of engine still changes after 3min?

Still very interesting to cut one turbo half and see how they made it work on turbo end?
Cheapest secundary turbos on Ovako is ~55€ + shipment 24€. Tempting...

 

cutting a turbo is the best way to find out. To see exactly in what chambers the air goes. I don’t believe on a valve inside turbo theory…… but only by cutting one …. Can be seen.
but the final ideea is clear. That’s why all second hand turbos leak ….. and are dirty. Missing air to keep oil in the turbo

 

I think too that what ever are inside the turbo for this mysterious pipe: Its not work now as it should on your engine causing oiling issues.
Sended an message for the fellow who i know have AJD-V6 with snap crank not far away where i live, but i don´t know is it 2.7 or 3.0? He bought complete (used) engine as replacement, so he should have turbos. If its 3.0 i ask if he like to give an turbo for scientific purpose?

 

👍👍👍👍👍👍👍👍👍👍👍👍👍👍

 

hello
or maybe…. He can lend the turbo for a test.
I tried to vacuum that line to see if it held pressure. It doesn’t….. but the needle of the reader tried to move from 0….. so……
more test idea without cutting a turbo in half.
one piece of secondary turbo, blocked the oil in and out slots, and a vacuum pump in the small pipe that comes from the airbox. And with an air compressor and a vacuum pump…. And maybe even a fume leak test machine….. observe what happens….. air goes out…. Through where? Negative and positive pressure…. How does it act……
maybe if it blows air through the oil in and out pipes………

that could provide all the answers for this air pipe to the turbo

so….. someone? 😊😊😊

 

ideea update

on YouTube, there’s a guy who builds range engines. Very knowledgeable

in one of his movies
this…

you see the name and minute to find the movie,he Says that if the clamp on that small hose that unites the snap turbo air pipe to the long metal pipe that goes to the air box on the motor, gets of and the whose is not properly pressurized,
“it’s going to disable the vacuum actuator for the secondary pump. “
So….. the front pipe from the airbox….. must be holding pressure…. All the way to the turbo. Why….. and how that helps the vacuum actuator on the back of the turbo….. I don’t know. But…… I guess whe gets his hands on a full turbo, needs to make some proper testing.
look at the movie on YouTube , minute 21 and someone give us an opinion.