<p>With the growing concern over the environmental impact of discarded tires, TPO offers a sustainable solution by converting waste into a valuable fuel source. This study investigates the viability of tire pyrolysis oil (TPO) as a substitutive automotive fuel by examining the impact of di-tert-butyl peroxide (DTBP) and 2-ethylhexyl nitrate (2-EHN) as cetane improvers on its performance and emissions characteristics. This research investigated the effects of adding 0.3% of each cetane improver to 20% and 40% blends of desulfurized TPO in a diesel engine under advanced injection timing. The results demonstrate significant improvements in engine performance. 2-EHN led to a maximum thermal efficiency increase of 5.8%, while DTBP achieved up to 3.1% enhancement. Ignition delay was found to be lower by up to 11% and 10% with 2-EHN and DTBP, respectively. Similarly, peak cylinder pressure was increased. Additionally, both additives effectively reduced emissions; 2-EHN lowered NOx by up to 29% and smoke emissions by 18%, while DTBP demonstrated reductions of 34% and 21%, respectively. However, the study also observed an increase in CO emissions, i.e., up to 14.2% with 2-EHN and 18.1% with DTBP, while HC emissions showed up to a 37% increase with 2-EHN and 43% with DTBP. While both additives enhance TPO’s potential as a diesel alternative, 2-EHN offers superior fuel efficiency, whereas DTBP demonstrates superior effectiveness in minimizing NOx and smoke emissions. This highlights the need for further research to optimize additive concentrations and engine operating conditions to minimize undesirable emissions.</p> Graphical Abstract <p></p>