Quote:
Originally Posted by tikamak
I am not capable of getting an oil analysis in this area of the world.
I will try to look for a close oil analysis firm.
I'm still at the break-in phase though.
The 15w-50 would be more suitable for your application, I chose 0w-40 because my car is basically street driving with some spirited driving and because the design of the rod bearings (2000 S54) was made with a castrol 5w-30 full synthetic oil.
The Castrol 10w-60 TWS was created after laps and laps on the track and should only be used for drivers that regularly take their cars to the track and drive very aggressively. In all cases, the 10w-60 is a severely upgraded 10w-40 with a high amount of additives to form an oil that is similar to a 60 weight on 100 degrees Celcius.
I'm not saying it's not good to use it, I'm saying that if you use it with street driving you might have bearing issues like i have found in my engine.
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But the engineers never intended for the S54 to rev to 8000 rpm, thus the S54 in the Z3M roadster has a 7800 rpm limit. In the US we had a massive recall after multiple cars spun bearings on the 5-30. BMW revised the bearing material and then made the Castrol 10-60 the required oil. You are correct about the 10-60 being based off of a 0-40 though , it actually has a lower viscosity after one track day than the Motul 15-50 does after several.It breaks down rapidly. My concern with you using 0-40 in a hot climate is that your bearing wear was from spirited driving not the 10-60. You needed more film strength at the bearing surface not less.