The presented work describes how spark calorimeter testing was used for parametric study and secondary circuit model calibration. Tests were conducted at different pressures, sparkplug gaps and supplied primary energies. The conversion efficiency increases and the spark duration decreases when the gas pressure or the sparkplug gap size is increased. Both gas pressure and sparkplug gas size increase the positive column voltage which represents part of the electrical energy delivered to the gas. The opposite direction occurs when the supplied primary energy is increased.The testing results were then used to calibrate the secondary circuit model which consisted of the sparkplug, the sparkplug gap and the secondary wiring. A step-by-step method was used to calibrate the three constants of the model to match the calculated delivered energy with test data during arc / glow phase.