The use of biodiesel has been widely accepted as an effective solution to reduce greenhouse emissions. The high potential of biodiesel in terms of PM emission reduction may represent an additional motivation for its wide use. This potential is related to the oxygenated nature of biodiesel, as well as its lower PAH and S, which leads, in general, to lower PM emissions as well as equal or slightly higher NOx emissions. According to these observations a different behavior of the Aftertreatment System (AS), especially as far as control issues of the Diesel Particulate Filter are concerned is also expected.The competition with the food sector is currently under debate, thus, besides second generation biofuels (e.g. from algae), the transesterification of Waste Cooking Oil (WCO) is another option, however needing further insight. More specifically, the impact of fuel distillation on engine performance and emissions is still not very clear, and understanding the effect on the AS system and particularly the DPF equilibrium point, may be important.In this paper an experimental-numerical study of a DEUTZ 4L off-road Diesel engine coupled to different size DOC-DPF systems is proposed. A 1D/0D model tuned on the experimental data has been used to evaluate the performances of different ASs by varying fuel and AS design. Experimental data have been gathered at the engine test bench of the University of Rome Tor Vergata, by using baseline fossil fuel (B06) and blends (30 % vol) with both distilled and non distilled WCO biodiesel. Data have been acquired during loading of two ASs, to the simplified DOC-DPF models that are able to reproduce the main physical phenomena such as oxidation, filtration and pressure drop. Multiple hour operating conditions have been simulated through the tuned model and results indicate that equilibrium point is much more easily achievable with the B30 fuel, and that blending of distilled biofuel offers advantages with respect to the non-distilled one.