@Wild one
Contemplating some more, Mopar didn't differentiate fuel octane rating recommendations from the higher compression 5.7 to the lower compression 6.4 BGE engines in truck owner's manuals.
Do you think the compression ratio difference was too insignificant to drop the 89 to an 87 recommended in the 6.4?
In other words, you're saying running 89 in the 6.4 is less likely to have any pinging than with the 5.7?
Without datalogger data I'm becoming more inclined to run 91 Top Tier, because those corporate bozos won't answer technical questions about their damn products. I can afford it because I don't put that many miles on unlike some of you. I'm also thinking Top Tier gas certification, especially Shell (which overspikes additive beyond TT) would clean any deposits formed from incomplete combustion of 91 octane gasoline using 89 octane engine ignition timing?
Thoughts?