M1 V-Twin has much better zinc and phosphorus specs, and it is a known quantity from my analysis over a 5000+ mile oil change. My M1 UOA showed 162 ppm boron, 61 ppm moly, 2160 ppm calcium and 107 ppm magnesium. The UOA did show lower zinc and phosphorus numbers than M1 specs show, but still healthier in quantity than Supertech. M1 stays in grade and shift quality in a shared sump simply does not fall off. I can see using a partial quart of Supertech to top off an oil change instead of cracking open a fourth quart of the M1. But the M1 definitely has the add pack I would choose on the whole.
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