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To improve the speed and accuracy of engine testing, the spark (gasoline)/injection (diesel) timing can be optimized based on the location of the 50% mass fraction burn point (α50) rather than the traditional approach of "sweeping" timing to find the most efficient point. Results from both gasoline and diesel engines show that setting α50 to around 8° ATDC gives optimum efficiency for most circumstances. An exception is the case of highly unstable combustion, where the misfire rate may also be strongly dependent on timing. For diesel engines this method is effective in finding the timing for best efficiency but in practice the chosen injection timing may be driven more by the need to optimize emissions. This technique has been implemented by incorporating a burn angle controller into the MAHLE Flexible ECU (MFE), a powerful and highly adaptable engine controller.