The firing order of an engine can be a very complex thing. It is determined by the design of the engine and the engineers at the OEM, long before you ever get your hands on (or in) it. While on most engines, the firing order is the firing order, period; paragraph, there are a few notable exceptions (largely in GM engines).
Whether or not you know the exact firing order of your particular engine you should know what a firing order is. Simply put, the firing order is the sequence of each individual cylinder’s ignition and power stroke. If it’s right, the engine will purr like a happy feline, and power will be delivered as efficiently as possible.
While it’s something that can be memorized on paper, and repeated like the digits of Pi, most people can’t fully visualize firing order in their head. It’s like reading about the Grand Canyon and then seeing it in person. However, thanks to this cool video, some LED lights, and some wiring wizardry, you can “see” firing order.
At first, the academic sequence of 1-3-7-2-6-5-4-8 seems simple enough to grasp although looking quite random. Then it jumps up in speed and you realize that the demonstration is only at idle speed. At idle, you start to see some patterns forming (camera framerate notwithstanding).
Once the simulation gets to between 2,500 and 3,000 rpm the only pattern visible is where the camera’s rolling shutter framerate syncs up with the otherwise undetectable pattern created by the firing order. As the RPM increases, you start to see second- and third-order harmonics with the camera’s framerate (but that’s a whole different nerd topic).
Peaking at 9,900-ish rpm, the demo rig winds back down to idle speed, where if you look close enough you can start to pick up on some physical patterns in the firing order. Whether you are interested in the visualization of firing orders, or just a fan of flashing lights and ASMR sounds, this video is worth the watch.