FACTORS AFFECTING EXHAUST SOUND OF AN ENGINE EXPLAINED !!!

You might have heard different exhaust note of motorbikes and cars. For example, the exhaust sound of the Royal Enfield Classic 350 is completely different from Kawasaki Ninja 300. In this article, we will discuss various factors that affect the exhaust sound of an engine.

But, before we discuss that, a brief primer on sound: It originates as vibrations that cause air-pressure disturbances that hit our eardrums. The frequency, or Hertz (Hz), of a sound wave—how many times the wave oscillates in a second—determines how our brain processes and interprets it as a distinct pitch. A higher frequency makes for a higher pitch, and vice versa. A car’s engine under load plays a range of frequencies, but its root note—the pitch its musical chord is built on—is defined by its so-called dominant frequency.

These sound-generating vibrations derive from the combustion in each cylinder and the corresponding pressure waves in the intake and exhaust systems. They are all keyed to the engine’s rotational speed; as revs rise and fall, the pitch goes up and down.

FOLLOWING FACTORS AFFECT THE EXHAUST SOUND OF AN ENGINE:

1.) Air induction-  In most cars, this is damped heavily. If you have a k+N universal one, you will hear the hiss. Carb engines made a much more delightful noise. Seen an Alfa or was it a Ferrari with triple carbs. Intake manifolds also play a part in the induction noise.

2.)Top Part of Engine- More parts means more music or noise - double overhead cams should make more interesting sounds. Belt driven cars are a little quiet. It all depends on tolerances and valve lifts. Pushrod engines generally sound harsh at high speeds. So, camshaft, valves and other parts of an engine which are located at the upper part of the engine also determines the sound of an engine.

3.)Bottom Part of Engine- It depends on bore, stroke and the number of cylinders. If an engine is having a larger stroke, we will get thump like sound that we get in Royal Enfield. If the number of cylinders in an engine is more than one it will produce better sound as compared to single cylinder engine.

4.)Exhaust- The exhaust construction is a big influence: which cylinders are combined into one pipe, separate exhausts per bank or combined or separate with a balance pipe, material.

5.)Turbo- It actually muffles the car, produces hiss sound when the turbo comes on.