I've been running 93 octane for about five tankfuls now. I think I'll get a gallon or two of race gas next fill-up to make sure I'm at least 93 octane on average.

I've been running the 87 octane performance/tow tune from 5 Star for maybe a month now. Its much better than stock but since selling my 6.7, I'm still somewhat disappointed at times. If it was just a daily driver, that would be one thing. But I tow landscape equipment in town half the time, an 18' enclosed trailer on the highway the other half. The truck gets driven without a trailer less than 5% of the time its on the road.

I know the 6.7 is a whole different animal. Maybe I need to lower my expectations. But when she's screaming in third or fourth gear on the interstate just to keep it at 67 mph on a slight incline, it gets old.

For those running the 93 octane fuel, do you think its worth the extra .40/gallon at the pump?

 

I've been playing with the 93 to see if mileage was any better. It seems to be a little better but not worth the .40/gallon as a pay back.