Originally Posted By: ammolab
Jim: I don't see any "spec" in my 2011 BMW manual that would eliminate any oil on the basis of "zinc". "JASO MA" is not a concern on the Air or Air/oil cooled BMWs as far as I know.
I think it has some viscosity recomendations and "SJ" Oil or better. I will check tonight when I get home.
I wonder if I really care about the "cat". My bike is N Mexico plated as I am moving there next year...no inspection or emission testing. Would I know if it was harmed by a high zinc oil?
Is it correct that there is no maximum limit on ZDDP in the SJ spec?
I admit to being out of my element, so I stand to be corrected. If I'm not mistaken if your cat is not working to minimum spec'd efficiency as measured by your O2 sensors, you should get a check engine light. How the engine reacts until that condition is resolved is uncertain to me. Some engines for example go into "open loop" mode when there is an O2 sensor issue and run rich until the condition is corrected. That would theoretically not be ideal.
If it is the case that zinc could do more than lower the efficiency of the catalyst by for example plugging the cat, then I think you'd notice that too.
In either case it might be the case that you'd have to replace the cat, or hollow it out and flash the computer to not throw a code as a response.
I guess I'd want to have some certainty around those issues before I did it.
You'd have to condition everyone's advice based on how much oil your bike loses to blowby. Mine uses almost nothing, so none of this might really end up being an issue. If we were talking about certain recent Honda V6's that are designed with low friction (higher blowby) oil control rings, then it might be a more sensitive subject. Just one more thing to factor into your consideration.
