Diethylene glycol dimethyl ether (DGM), also known as diglyme, has a very high cetane number with fuel-bound oxygen of up to 36%, it has strong potential to reduce diesel emissions. This work is an investigation of the turbocharged diesel engine's emissions and performance parameters using coconut biodiesel-diglyme-diesel blends. Coconut biodiesel was used as an oxygenated fuel, while DGM was utilised as an oxygenated additive for its excellent cetane number and higher fuel-bound oxygen. The reason for adding diglyme to coconut biodiesel blends is to study the influence of cetane number and fuel-bound oxygen on performance, combustion and emission characteristics. There were five fuels tested in this study. To compare the performance, combustion and emissions data, a regular diesel was used as a base fuel. The neat diesel (100% diesel) and the neat coconut biodiesel (100% coconut biodiesel) were designated as diesel and Ox4 respectively. Blend of 70% diesel + 30% coconut biodiesel is abbreviated as Oxl, 70% diesel + 20% coconut biodiesel + 10% diglyme blend is abbreviated as Ox2, and 70% diesel + 10% coconut biodiesel + 20% diglyme blend is labelled as Ox3. All blending percentages were based on a volume basis. Engine experiments were performed with an unmodified Cummins 6-cylinder common rail diesel engine. The engine was fitted with precision measuring instruments. Using GT-Power, a one-dimensional (1-D) model was developed to examine some key performance parameters with those of experimental data. Most of the performance results show the variations between experimental and simulation data were within 10%.