Quote:
Originally Posted by ska325xi
The tradeoff of better engine protection is made, over longer emissions performance"
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I think that is the key statement. IMHO engine oil is there to protect your engine, not the catalytic converter.
FWIW my old WRX engine was filled with Shell Rotella T 15W40 or Mobil 1 Delvac 5W40 (heavy duty oils designed for diesel engines, and have a very high level of antiwear additives such as phosphorus) for many thousands of miles and there does not appear to be any damage to the cats (it passed CA emissions test easily with close to 100k miles on the odometer)
honestly I think the oil discussion is very easy for BMW. LL01 standard is required and BMW conveniently gives us a list of oils that meet this standard. done!