If you say your truck's got a Cummins 6.7, it would be reasonable to assume you'd fill it up at the pumps with the big green ... engines that are "fuel agnostic," and is a clean-sheet design ...

The minimum fuel saving of 3%, says Fersa, adds up. Assuming 150,000 km (93,200 miles) per truck per year, a baseline fuel total is around 60,000 liters (13,200 gal) of diesel.