In compression ignition engines, the use of hydrogen-diesel dual fuel mode has a positive impact on engine performance and emissions. To enhance the impact of hydrogen in dual-fuel mode, it is crucial to properly adjust the energy ratio and design the combustion chamber for dual-fuel mode. This study focuses on these two situations. The study conducted a literature review and designed and manufactured two combustion chambers (Natural Gyration 1, Natural Gyration 2) suitable for dual fuel mode. Using the original combustion chamber and the manufactured combustion chambers, at a constant engine speed of 1850 rpm, at five different loads (3, 4.5, 6, 7.5, and 9 Nm), and at three different hydrogen injection times (1.6, 1.8, and 2.0), tests were performed. Engine performance and emission data obtained as a result of the tests were examined. Tests revealed that at a load of 9 Nm and with a hydrogen energy ratio of 12%, the Natural Gyration 1 combustion chamber increased the internal cylinder maximum pressure by 1.41%, reduced the specific energy consumption by 2.29%, and reduced particulate emissions by 8.82%. On the other hand, it was determined that the Natural Gyration 2 combustion chamber reduced the maximum cylinder internal pressure by 1.98%, increased the specific energy consumption by 2.66%, and soot emissions by 5% at the same load and hydrogen energy ratio.