Anyone else taking notice the API rating changed to "SN Plus" on not just Motorcraft oil but others? Apparently it has to deal with low-speed pre-ignition in DI engines. Is this that big of a concern? how do you know if your engine suffered LSPI?

 

Its not a concern for any engine in the F150's.

 

What engines are more prone to this?

 

Small displacement turbocharged direct injection engines gas engines, mainly 2.0L or smaller 4 cylinder engines. The problem has several variables, the main culprit of which was manufacturers seeking maximum mpg's by lugging motors at lower RPM with small high torque turbos, especially US car manufacturers. Updated oil specifications are really only a band-aid, as the oil was not the cause in the first place (but it can have an effect for better or worse depending on additives). The all around fix for this is better ECU tuning and shift logic, better DI designs including adding port injectors like Ford has done, and as you know new oil specifications with reduced additives that are alleged to aggravate LSPI and more additives like Moly that are stated to help quench LSPI.

LSPI is really just a growing pain with small displacement DI engines, and they should be able to resolve the issues with future designs.