AMSOIL Premium API CJ-4 5W-40 Synthetic Diesel Oil (DEO) Fuel Economy (697k PDF)
The Environmental Protection Agency (EPA) Federal Test Procedure (FTP) confirms AMSOIL Premium API CJ-4 5W-40 Synthetic Diesel Oil (DEO) improves fuel economy through virtually all driving scenarios compared to conventional 15W-40 diesel oil.

AMSOIL Premium API CJ-4 5W-40 Synthetic Diesel Oil (DEO) Shear Stability (644k PDF)
Kurt Orbahn Shear Stability testing (ASTM D-6278) reveals AMSOIL Premium API CJ-4 5W-40 Synthetic Diesel Oil (DEO) maintains outstanding shear stability, even at 4 percent fuel dilution.

AMSOIL Premium API CJ-4 5W-40 Synthetic Diesel Oil (DEO) TBN and Viscosity (363k PDF)
Compared with competing diesel oils, AMSOIL Premium API CJ-4 5W-40 Synthetic Diesel Oil (DEO) provided superior TBN and viscosity retention over 400 hours of severe-service operation in a refuse hauler fleet employing Navistar DT466 diesel engines, which are notoriously hard on motor oil.

Diesel Recovery Cold Filter Plugging Point (794k PDF)
Cold Filter-Plugging Point (CFPP) testing shows AMSOIL Diesel Recovery (DRC) lowers the cold filter-plugging point of diesel fuel more effectively than the competing brand.

Diesel Fleet Fuel Economy Study (G2904) (446k PDF)
Testing completed in compliance with the industry-standard SAE J1321 In-Service Fuel Consumption Test Procedure demonstrates use of AMSOIL synthetic lubricants can increase fuel economy in short- to medium-haul diesel applications and, in this case, did by 6.54 percent.