Two types of new carbon nanostructures with the graphitic structural unit were synthesized viz. nanographite (< 50 nm) and spherical carbon nanoparticles (~10 and ~ 50 nm). The above two nanoparticles and micro graphite were used as an engine oil additive to enhance the tribological properties. The tribological and thermophysical properties of all lubricants were also evaluated. The tribological tests exhibits enhancement seven times in wear and more than 13 times in friction of the nanographite-based nanolubricant. The performance assessment of nanographite-based nanolubricant exhibits reduction in ~15.2% in total fuel consumption, 18% in brake specific fuel consumption, 22% augmentation in brake thermal efficiency, 28.23% enhancement in heat carried by a water jacket, and 5.13% reduction in exhaust gas temperature compared to base engine oil. Marginal to significant reduction in the emission of harmful gases is also observed. The results show the potential of developed nanolubricant for environmental protection and energy-savings.