The Firing Order

The Secret to Your Engine's Inimitable Voice

Beyond raw power and performance figures, there's a dimension of the automobile that directly touches our emotions: the engine's sound. This roar, this mechanical melody, is far more than just noise; it's a signature, a promise of sensations. At WOT, as engine specialists, we appreciate the engineering behind this symphony. But how did sound become so important to manufacturers? And why does every engine have its own voice?

When Sound Became a Brand Signature

Historically, engine sound was a direct consequence of its operation—noisy, but not necessarily melodious. The importance of sound as a distinctive and desirable element began to emerge with sports and luxury cars. In the 1960s and 70s, during the golden age of American V8s and Italian V12s, "sound" became an integral part of the driving experience.

For brands like Ferrari, Lamborghini, or Porsche, their engines' sound signature became as iconic as their design. It was no longer just an indicator of power, but a vector of emotion, a mark of recognition, and a major selling point. An engine that "sounds good" suggests performance, mechanical nobility, and craftsmanship.

Today, with the advent of electric powertrains and increasingly strict noise regulations, manufacturers are spending fortunes on research and development to sculpt the acoustics of their vehicles. For internal combustion engines, it's about filtering out undesirable noises and amplifying pleasing frequencies. For electric vehicles, it's about creating artificial sounds that evoke the thermal experience.

The Unique Timbres

Two engines of the same architecture, like two V8s, can have radically different sounds. The same goes for a V6 and an inline-6 (I6). These differences in "timbres" are due to several mechanical and design factors:

• Cylinder Firing Order: This is undoubtedly the most important factor, which we'll describe in more detail below. It refers to the sequence in which the spark plugs in each cylinder ignite. Every engine has a specific firing order, designed to optimize balance, power, and reliability. But this sequence directly influences the regularity of the sound impulses at the exhaust.

• V8 Example (Flat-Plane vs. Cross-Plane): A classic American V8 (cross-plane crankshaft) has a firing order that generates a deep, somewhat irregular sound, that famous "burble" or "rumble" that's so beloved. This is because the explosions are not perfectly spaced in the cycle. In contrast, a sporty European V8 (flat-plane crankshaft, like in Ferraris or McLarens) has a firing order that produces a higher-pitched, more raucous, and more regular sound, almost akin to two distinct four-cylinders. It's a more "racy" sound.

• V-Angle (for V engines): The angle between the cylinder banks (e.g., 60°, 90°, 120°) affects the regularity of the explosions and thus the sound. A 60° V6 can sound different from a 90° V6.

• Crankshaft Configuration: As mentioned for V8s, a flat-plane or cross-plane crankshaft fundamentally changes the sequence of explosions.

• Intake and Exhaust Design: Exhaust manifolds, the length and diameter of the pipes, the presence and type of mufflers, active valves, all these elements are designed to sculpt the sound that reaches our ears. Incidentally, the distinctive sound of a Subaru Impreza Boxer engine, the famous "rumble," comes from the design of its unequal length exhaust headers (UELH). These different lengths mean that the exhaust pulses from the cylinders don't arrive synchronously, creating that characteristic rumble.

• Engine Speed: An engine's sound changes drastically as the RPM increases, transitioning from a deep growl to a high-pitched scream.

• Number of Cylinders: A greater number of cylinders offers more possibilities for spacing out explosions and generating more complex and generally richer frequencies.

The Cylinder Firing Order: The Engine's "Score"

The cylinder firing order is the sequence in which an engine's cylinders receive the spark and ignite. It is crucial for:

• Engine Balance: Reducing vibrations and mechanical stress.

• Performance: Optimizing cylinder filling and exhaust gas evacuation.

• Sound: Defining the rhythm of the explosions that produce the sound.

This order is sometimes engraved on plaques near the engine, particularly on prestigious vehicles like Lamborghinis. It's a point of engineering pride and a way to highlight design precision.

For example, a typical V6 might have a firing order of 1-4-2-5-3-6, while another V6 might have a different sequence. These variations, though subtle on paper, translate into distinct sound signatures at the exhaust.

At WOT: An Attentive Ear to Every Optimization

At WOT, while our core business is performance optimization through remapping, we fully understand the importance of engine sound. A successful remapping isn't limited to numbers on a dyno; it must also enhance the driving experience. This involves respecting the engine's acoustic character, and even improving it, without compromising anti-pollution standards.

The harmony between performance and sound is a delicate balance we strive to achieve, so that every acceleration is not only powerful, but also melodious.