Originally Posted by Artemis
Fact check of what I was told: real ///M engines require 10W60. However the engine used for the 1M (N54) is not a 'true' ///M engine. The Twin Turbo got to stick with 5W30. However, if I want to push the 1M hard on track 10W60 would be more appropriate. Here you got it - so the story goes (at least the one I was told).
+1. I was told the same thing at Manhart Racing GmbH when we toured their shop. They said even though BMW says to use the 0w30, 0w40, 5w30 or 5w30 long life oils... Manhart said there is no better oil for track use or cars that are pushed hard on the street than the Castrol TWS 10w60 oil. In fact they said every car that they service or build - and that is what they use.
They said the reason is the oil doesn't allow metal on metal contact at extreme oil temps, that you often see at the track or on the Autobahn.
I asked them that isn't a 10w60 oil kind of think to use all year round, especially in a cold (winter) climate like Germany ? ...and they said most M owners don't drive in the winter time!
So... While I think Castrol Edge 0w40 Long Life
(full synthetic or the oil sold at BMW in the USA)) oil is best to use in any N55 or N54 engine... for cars that are tracked maybe you should use TWS.
I will continue to use German Castrol Edge FST 0w40 LL oil though.