Just finished a 560 mile run east on I-10 in the 2012 SRT today, and it turned in its best ever fuel economy- 26.2 mpg. That's a full 1 mpg better than the best prior, and conditions were pretty much the same as usual for this trip- speed limits mostly either 70 or 75, with a few stretches of 60. Temps in the high 80s. No wind for the first 3 hours, then a pretty stiff crosswind that did drag the economy down a few tenths for most of the day. Then sheltered from the wind by pines the last 2 hours of the run.
The only significant changes I can think of are that the car's another few thousand miles broken in than the last trip (20,900 mils at the end of the day), AND I installed a PCV oil separator a few months back. I installed it to keep the intake clean, but I know that oil mist causes detonation and that in turn causes the computer to retard timing (that's actually how the catch-can makers market them- "lose less timing and get more power." Maybe cruising in O/D without the separator caused a little more timing to get pulled than I had been assuming?
Anyway, I won't be convinced until I repeat it... but its not like I had a 20-mph tailwind or anything else obvious. In fact, I've made the trip WITH a slight tailwind once before and not done this well.
The only significant changes I can think of are that the car's another few thousand miles broken in than the last trip (20,900 mils at the end of the day), AND I installed a PCV oil separator a few months back. I installed it to keep the intake clean, but I know that oil mist causes detonation and that in turn causes the computer to retard timing (that's actually how the catch-can makers market them- "lose less timing and get more power." Maybe cruising in O/D without the separator caused a little more timing to get pulled than I had been assuming?
Anyway, I won't be convinced until I repeat it... but its not like I had a 20-mph tailwind or anything else obvious. In fact, I've made the trip WITH a slight tailwind once before and not done this well.