The reason it's that specific order is to optimize the engine's balance and smoothness. Firing orders are carefully designed to:
* Minimize vibrations: By strategically spacing out the ignition events, the engine's reciprocating forces are better balanced, leading to smoother operation and reduced vibrations.
* Optimize power delivery: The sequence helps ensure consistent torque output throughout the engine's RPM range.
* Reduce stress on engine components: A well-designed firing order reduces stress on the crankshaft, connecting rods, and other internal parts.
The precise order (1-3-5-6-2-4 in this case) is determined through extensive engineering analysis and testing, considering the crankshaft's design, the connecting rod geometry, and other factors. Slight changes can significantly impact the engine's performance and longevity. There's no simple, easily explained reason *why* that specific order is best beyond the overall goals of balance and efficiency – it's an optimized solution arrived at through engineering.
