This week, I’m on my regular run from Charlotte, NC to Laredo, TX. En route to Meridian, MS, my thoughts turned to a question someone had posted on my Facebook page. The question was in regards to the great fuel mileage numbers from my Cascadia Evolution and this individual was wondering if I could hit 11 mpg if I reduced my speed to 55 mph. The question was posed after I had just completed the outstanding mileage of 10.05 mpg on 1,438 miles.
Early in the week, I was running ahead of schedule and with a load weight of 66,000 GVW, it was a good opportunity to evaluate what the fuel mileage results would be running at a maximum cruise speed of 55 mph. I stopped to fuel in Meridian, MS and set the cruise at 55 mph in the 70 mph zone and headed for Laredo, TX. To my surprise, the arrival time in Vidor, TX was about the same as if I had run my normal 65 mph cruise speed. This was due to the E-Coast feature in my Detroit DT12 Transmission.
Normally when running at 65 mph on a downgrade, the transmission will shift automatically into E-Coast mode which allows me to quickly hit the 70 mph maximum speed. At this point, I’m required to either hit the brakes or engage the Jake brake in order to maintain the correct speed limit. By having the cruise set at 55 mph, I had the luxury of a 15 mph buffer zone to the speed limit of 70 mph. This enabled me to coast for a higher percentage of time in comparison to cruising at 65 mph. In the end, the E-Coast feature of my transmission not only was able to maximize my fuel efficiency but also shortened my arrival time by allowing me to coast to a higher speed vs. the set cruise speed of 55 mph.
I wanted to share with you the outstanding fuel results from the first 884 miles of this experimental trip to Laredo, TX. The first leg ended in Vidor, TX with an indicated 12.9 mpg average. I shut down overnight and continued on to Laredo, TX in the morning. While traveling across I-10, I encountered a cross wind all day until arriving in San Antonio, TX. The results were an average fuel mileage of 12.3 mpg. I then turned onto, I-35 south towards Laredo, TX and experienced a headwind. Upon arriving, I checked the fuel mileage once again and it was 12.4 mpg for 884 miles since leaving Meridian, MS.
I’m pleased with the early results however I normally hit a passive regen approx. every 1,400 miles resulting in a lower fuel mileage average.
Today, I’m reloading in Laredo, TX and will begin my journey back to Charlotte, NC. I’m going to continue cruising at 55 mph in order to complete a round trip of approximately 2,885 miles. I’m excited to see what the final outcome will be for the Cascadia Evolution. At that point, I’ll need to evaluate all the figures and determine whether to continue cruising at 55 mph. Stay tuned for my next update.