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Originally Posted by tfunk88
Just curious, what did they change to figure out how to mitigate buildup? I know from the N63 to the N63TU they improved the valve seals and I would assume the ability of the PCV system to filter oil vapor back into the engine vs into the intake…but I know mine was definitely venting some oil into the intake.
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I think a few different things. The oil separators built into the PCV systems improved. Another major source of oil was compressor seals which have improved. Both of those sources combined to coat the whole induction system in oil. When the engines ran with high overlap (dual cam phasers do that to dethrottle for fuel economy) there was sooty combustion gases that get pushed into the intake and stick to the oil. Once known, the calibration can be adjusted to be less aggressive. Combustion systems (charge motion, injector targeting, spray geometry, injection pressure) also improved to have less combustion soot. Put it all together and it’s less of a problem than back in the N54 days.