Quote:
Originally Posted by BeatupVR4
You are definitely more informed that me but I was under the belief that the CHRA and compressor cover are built by MHI and shipped to BMW where they are married to the Boysen turbofolds, cats, catback.
I thought this was the issue with the wategate bushing going bad being made by Boysen. I've had TD03/04/05 MHI turbos with 200k miles on them that still function perfectly. Wastegate included.
When I shipped my OEM turbos back for a core there was zero axial play and the standard amount of radial play for a journal bearing turbo but the wastegate bushings were toast as well as the arm ovaled out severely.
|
If you are requesting the precise build strategy of the Authentic OEM's, it would be like this:
1) Boysen produces the exhaust manifold, double wall insulated air gap design.
2) MHI produces the entire turbocharger (Compressor housing, CHRA, Turbine housing/internal wastegate assembly)
3) One or the other above receives the counter component, or perhaps even another 3rd party; and both items are married to one another.
Regarding OEM N54 turbo failures, coming from one who has without question dismantle more of them than anyone else in the world (literally in the thousands), the failure modes are in this order:
1) Wastegate Wear- Nearly every unit has some degree of wastegate wear, most of them very large amounts and very few low amounts. It is inherent in time due to the vacuum control wastegate assemblies, as the hardware is left open most of its life and is subjected to constant unlubricated movement even in its "inactive" states (ie. it only gets a "break" at very high WGDC's).
2) Turbine seal and ductility- With many thousands of heat cycles and over many years of service, the seals simply lose their tension and effectively can not keep a good seal with the Centersection. This is noted as nearly every unit, close to all of them, I disassemble the piston ring turbine seal simply snaps into pieces (ie. brittle) when trying to remove. Also most all of them are squeezed into the groove, with zero "outward spring" remaining.
3) Thrust bearing failures- Many core units do come back with thrust bearing wear. Most are likely from tuned N54's and thus were pushed over some amount of time. If one were to run OE boost levels this likely would not ever be much of a concern.
Rob