octane rating and engine performance
In Texas, the minimum octane rating is 87. On a recent trip to Glacier, I noticed a lot of the fuel in states like CO, WY and MT, the octane was 85, and you had to buy the mid-grade to get 87 and abov...
Forum Discussion
Ram recommends 89 for the 6.4. Ram says 87 is adequate. I've run both and haven't noticed any difference.
