As many of you know, I have been working on the initiative we called Project 70/+10. For those of you who haven’t been following along, the goal of this project has been to attain a double-digit fuel economy average. The parameters of this project were to cruise at speeds up to 70 mph where safe and legal. This project was started with my last Cascadia named New Blue. The end result for New Blue's fuel economy was 9.513 mpg on average with 548,315 miles on the odometer.
New Blue was a 2017 Cascadia AeroX with a 400 HP / 1750 FPT Detroit DD15 engine followed by a Detroit DT12 automated manual transmission direct drive, and a Detroit 6x4 rear axle configuration with 2.16 rear axle ratio with active lube management riding on Michelin wide base single tires. With New Blue, the cutoff point of being able to achieve double-digit fuel economy was 70 mph. There were a few occasions where I was able to attain 10 mpg averages for a tank full, however not often enough to keep the average lifetime in the double-digit range.
This project continued with our 2022 Freightliner Cascadia, which we named Celeste. Celeste is powered by a Detroit DD15 455 HP / 1850 FPT to a Detroit DT12 automated manual transmission with a .78 overdrive ratio coupled to a Detroit rear axle with a 2.61 ratio with active lube management and a Hendrickson OPTIMAAX liftable pusher axle, also riding on Michelin wide base single tires. Another addition that started towards the end of my time with New Blue, was a Hendrickson lift axle on my trailer, as well as on the truck. With this setup, I can go from 5 axles on the ground, or if I am lightly loaded or empty, I can travel on 3 axles. Traveling on 3 axles, rather than on 5, helps with less parasitic drag, less tire wear, and tolls.
On the current truck, you may notice that I have an overdrive transmission with a .78 ratio combined with the 2.61 rear axle ratio. This equates to an overall ratio of 2.03, which helped lower the rpm to approximately 1350 at 75 mph, vs.1400 rpm's with the previous truck, which had a direct drive transmission with a 2.16 rear axle ratio. With each of these trucks, I pulled the same Utility 4000DX 53' dry van trailer. The trailer is equipped with a Nose Cone, experimental Fleet Engineers full-length skirts, and also rides on Michelin wide base single tires. I’m pleased to announce that this combination has led to an average fuel mileage of 10.004 at 54,773 miles on the odometer. The gross combination vehicle weight varied between a low of 42,000 and 78,000 pounds with the majority falling in the 55,000 – 60,000 pound range.
The primary route for Celeste has been from Laredo, TX to Charlotte, NC, and back with zero empty miles since I load and re-load at the same docks at each end. At this time I would like to thank everyone from Freightliner, Detroit, Hendrickson, Michelin, Nose Cone, and Fleet Engineers who worked with me to make this project a success.
At this time, I’m suspending Project 70/+10 since it has been more difficult to maintain these speeds without having a lot of unnecessary interaction with other trucks on the highway, as many of them have slowed down due to the high cost of fuel. On top of that, with the price of fuel being at record levels, it seems that it’s a very good time to start a new project, which I would call Maximum Efficiency.
I’m now searching to find the optimum speeds to travel in, on the right lane of the highway, and have the least interaction with other vehicles. It’s still nice to know that I have the flexibility to travel at higher speeds, if the need arises, for customer satisfaction and profitability.