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Old 04-23-2013, 07:13 PM   #23 (permalink)
some_other_dave
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Quote:
Originally Posted by Old Mechanic View Post
I would suspect based on experience that PCV by itself might not be a problem as long as there is no recirculation of EGR. ...
Maybe the fuel injectors spraying onto the intake valves kept that area clean versus DI that would not.
The latter is the consensus view among MINI owners, at least. And it makes sense--gasoline is a pretty decent solvent, so having a nearly constant supply sprayed into the intake ports would tend to wash away any stuff that would try to build up. DI engines have no such cleaning spray. (Though as may have been mentioned, there are setups that also inject fuel into the manifold in part to help with the buildup!)

Rumor has it that other makers of DI engines are going to larger and more elaborate PCV systems to help separate out oil vapors, due to the carbon build-up problem.

-soD
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