Low speed pre-ignition (LSPI) frequency and whether the oil can pass the TEOST-33 test are affected by whether the detergents used contain calcium or magnesium. Sodium was also tested. That is not new information to many of us. What I found interesting is that it also matters whether the detergent is overbased or it is low based/neutral. It also matters whether the detergent is a sulfonate or a phenate. They didn’t test it but it also probably matters whether it is a salicylate. I also found it interesting how many of the formulations failed the TEOST-33 test. See toward the end of the patent in the link for the test results.
http://www.freepatentsonline.com/y2017/0015927.html
http://www.freepatentsonline.com/y2017/0015927.html