Zinc in the oil better for longevity?
Found in the comment section of Speedcar99 Youtubechannel:
"shell rotella t5 15w40. still has lots of calcium and zinc in it to protect the engine. they pulled the zinc out of t6 under 1000 ppm. no zinc no long lasting engine."
But might wear a little more on the catalytic converter?
https://www.youtube.com/watch?v=ujEJDDB7pBU&t=5s
