My Cascadia Evolution is about to reach its 35,000 mile mark. For those of you new to the blog, I’ll give you a quick rundown of the specifications on the truck… 72" raised roof sleeper, wheel base 225", 6x2 axle configuration, Detroit DD-15 455 HP 1550/1750 multi torque engine, Detroit DT12 direct drive 12 speed automated manual transmission, 13,300 Detroit steer axle Meritor fuel light tandem axle 2.50 rear axle ratio, locking drive axle, tires, Michelin steer axle XZA3Plus 275/80R22.5 LR H Drive axle XDA Energy 445/50R22.5 Tag XTA 445/50R22.5. I have chosen all of these
components to be as efficient as possible. In addition to these specs, my trailer is equipped with a nose cone, side skirts, wheel covers, plated cross members from the skirts to the rear, covered rain gutter and even the license plate has been moved out of the air stream to improve efficiency.
My GVW has been between 63,000-65,000 lbs. and my route usually consists of unloading/reloading at the same location. This enables me to have nearly zero empty miles. My cruise speed has been 65 mph were permissible. The results are that my average fuel mileage for the entire 35,000 miles is just above 9 mpg. This number would be a bit higher if I had not been doing numerous demonstration rides which typically have a negative impact on fuel mileage. (A normal demonstration ride usually includes demonstrating transmission shifting often.)
This outstanding fuel mileage is a tribute to how well the entire Cascadia Evolution package works in harmony with the latest aerodynamics, engine and transmission technology from Detroit combined with my aerodynamic trailer. During this initial 35,000 miles, I’ve been thoroughly impressed with how well the DD15 engine and DT-12 transmission from Detroit communicate with one another. Having the engine and transmission vertically integrated from one provider allows for the complete drive train to work in complete unison.
The new DT -12 transmission from Detroit is a marvel in itself as it seems to almost know what gear you’re going to need before you need it. Its abilities to skip shift and slip into E-Coast builds upon the overall efficiency of the Evolution package. On one occasion, I stopped at a traffic light on a steep downward grade and the truck was able to tell we were pointed downhill with a nearly 80,000 GVW. When the light turned green, the truck pulled out in 5th gear and quickly skipped to 7th gear. The skip shift function and the truck knowing to launch in 5th gear, enabled me to gain speed in rapid and efficient fashion. The other feature “E-Coast” slips the truck out of gear every time it senses when the engine is not needed. When performing this function, it’s so smooth that you’re not able to notice the action if you’re having a conversation with someone.
Below, I’ve listed the last 14 fill ups for your review. Note: these figures are not from the ECM as they are calculated from figures at the pump.
9.510 – 8.549 – 9.236 – 9.129 – 8.862 – 9.086 – 9.170 – 9.002 – 8.653 – 9.100 – 9.061 – 9.69 – 9.007 and 9.629
Note: On the 3 fuel mileage figures which are below 9 mpg, I conducted several demonstration rides with the truck and trailer which included shifting, lots of in town and shipping yard maneuvers. This tends to drop my fuel mileage significantly.