Fueling the Future

Jordan Greathouse
September 2024

A Real-World Test of the Kenworth T680

In the ever-evolving world of trucking, where fuel efficiency and environmental consciousness are paramount, the 2020 Kenworth T680 stands out as an example of good design and impressive performance. This article delves into the results of a 33-day real-world test conducted on a meticulously equipped T680 by our good friend, Cole Fairbrook, showcasing its fuel efficiency capabilities and highlighting the exciting potential for further optimization. Complete numbers are provided.

A Carefully Crafted Platform for Efficiency

The subject of this test was a 2020 Kenworth T680 with a 228" wheelbase, powered by the Paccar MX-13 engine, paired with a 12-speed automated manual transmission (AMT) and 2.64 gears. This configuration, combined with a 6x4 drivetrain, trailer wide-base tires, Fuel additives (Max Mileage FBC and Flashpoint), wheel covers, FASS fuel system, Fleet Air, and eco mud flaps are specifically designed to maximize fuel efficiency. The truck also incorporated various upgrades like PS-386 transmission oil, Rotella T5 10W30 engine oil with FR3, and FE 75W90 gear oil, further optimizing its performance.

Fuel Efficiency on the Open Road

Over the span of 33 days, the T680 traversed a distance of 14,419 miles, carrying an average of 24,450 pounds of freight, or a gross vehicle weight of 57,350 pounds. The truck predominantly operated at 55 MPH, with three days of driving at a faster 64 MPH. All 55MPH driving was done in direct drive at 1240 RPM and all 64MPH in Overdrive at 1100 RPM. The results are clear: the T680 achieved an average fuel economy of 10.14 MPG, consuming a total of 1422 gallons of diesel. This remarkable figure demonstrates the truck's ability to translate its design features into real-world savings.

Environmental Responsibility and DEF Consumption

The T680 doesn't just excel in fuel efficiency, it also sets a high standard in sustainability. The test revealed a commendable DEF (Diesel Exhaust Fluid) consumption rate of 314 MPG. This indicates the truck's strong commitment to minimizing emissions while delivering robust performance, reinforcing its dedication to sustainability and environmental responsibility.

The Pursuit of Optimization

While the T680 already demonstrated impressive fuel efficiency, the owner recognizes that there's always room for improvement. Further optimization through modifications such as steer tire covers, trailer side skirts, flow-below devices, and differential oil upgrades is estimated to increase fuel efficiency by an additional 11.2%, potentially pushing the T680 to an impressive 11 MPG.

The Engine Debate: Paccar MX-13 vs. Cummins X15

The owner acknowledges the ongoing discussion within the industry regarding the relative performance of different engine manufacturers, particularly the Paccar MX-13 and the Cummins X15. While the Paccar MX-13 generally achieves a 1 MPG advantage over the Cummins X15, the Cummins has the benefit of aftermarket tuning capabilities, potentially allowing it to achieve comparable levels of fuel efficiency. The owner believes that a Cummins X15 could achieve 10 MPG or more with the right modifications and tuning.

The Importance of Customization and Optimization

The T680's success story highlights the importance of a comprehensive approach to fuel efficiency. The owner emphasizes that it's not just about the engine, but about a carefully chosen combination of components, modifications, and driving practices. This holistic approach, involving upgrading oils, installing fuel system enhancements, adding aerodynamic components, and implementing fuel additive programs, is crucial for achieving significant fuel efficiency gains and is a key knowledge for anyone in the trucking industry.

The Future of Trucking

This real-world test of the Kenworth T680 not only showcases the power of customization and optimization in achieving significant fuel efficiency gains but also the truck's impressive performance. As the trucking industry continues to evolve, the need for fuel efficiency and environmental consciousness will only intensify. The T680, with its remarkable performance and potential for further optimization, exemplifies how the industry can embrace these challenges and pave the way for a more sustainable future of transportation.

Raw Data

Truck: 2020 Kenworth T680

Wheelbase: 228” 

Engine: Paccar MX-13 (Rotella T5 10W30 with FR3)

Transmission: 12 Speed Automatic Transmission (PS-386 Trans Oil)

Gears: 2.64 (FE 75W90)

Tires: Wide base    

Fuel Additives:

* Max Mileage

* Flashpoint

Aftermarket Accessories:

* Fleet Air Filter

* Wheel Covers

* Fass

* Eco Mud Flaps (Truck and trailer)

Days: 33 (6-20-2024 to 7-22-2024)

Miles: 14,419

Gallons: 1422

Fuel MPG:10.14

DEF MPG: 314

Speed:

* 30 Days, 55mph – Driven in direct drive at 1240 Rpm

* 3 days, 64mph - 64 in Overdrive at 1100 Rpm

Average Freight Weight: 24,450 or 57,350 Gross  

Loads: 12

Average length of haul: 1106 miles

Deadhead miles: 1114

Testing By: Cole Fairbrook

Written by: Jordan Greathouse, Pittsburgh Power Inc., 3600 S. Noah Drive, Saxonburg, PA, 16056 Phone (724) 360-4080; Email: [email protected]; Website: www.PittsburghPower.com