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Thread: WHAT MAKES THE FERRARI SOUND SO UNIQUE??

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    Default WHAT MAKES THE FERRARI SOUND SO UNIQUE??

    Well I am doing a Ferrari-story for a magazine/newspaper, and really would like to explain why the noise from a ferrari engine is so unique to any other engine, even v8's. I am writing about the 348...Any tips?
    I know there is a diffrence in the V-shape?
    Thanx guys.

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    GrahamS's Avatar
    GrahamS is offline Crop rotation in the 14th century was CONSIDERABLY more widespread after John... Admin dude
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    The flat plane crank is a major factor, which means it has the same firing pattern as two independant 4-cylinder engines

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    GrahamS's Avatar
    GrahamS is offline Crop rotation in the 14th century was CONSIDERABLY more widespread after John... Admin dude
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    Robbed from elsewhere

    Besides the engine, there are a number of accessories which produce noise in the engine compartment--such as the alternator, AC compressor, engine cooling fan, etc. These soundwave components which vary with the engine combustion noise since they are driven by belts connected to pulleys which are being rotated by the engine crankshaft. Depending on the pulley ratios, these they may or may not produce a noise that is a harmonic of the engine. There's a few other components of noise as well, ie. the noise of the rubber tires rolling over asphalt, the air being disturbed as the car moves forward (or backward), and the gears in the transmission meshing and unmeshing. If the gears are straight-cut, as in reverse, you get the very noticeable whine. In addition to these major components of engine noise, some noise results from the turbulent air flow over accessories such as the radiator, radiator fans, and alternator. Finally, you can get lots of variation from the same noise source if the noise(s) reach you after being reflected off walls or other surfaces.

    Focusing on the engine note, the combustion of fuel in the engine cylinders is the major source of this noise. This combustion is an explosion like a gunshot, basically a sharp, flat sound or report. The exact nature of this report (how it sounds) is determined by the frequency, separation, and intensity of the explosions. These are determined by the cam profile, the size of the cylinder, the shape of the top of the piston, the compression ratio, the compression rate, the shape and location and position of the intake and exhaust valves, and the engine materials and their thicknesses. Additionally, how the explosion soundwaves reverberate through all the other structures in the engine bay, and the paths they follow before reaching your ears also influence the sound you hear or bass notes that you feel.

    Because there's multiple explosions happening each second, the noise pulses combine into a continuous burble or rumble or drone. The combustion(s) produces pressure pulses at a rate proportional to engine speed (the "revs"). In a four stroke engine, combustion in each cylinder occurs once every two engine revolutions, i.e. there are four pressure pulses per crankshaft revolution in an eight cylinder engine. As the revolutions increase, the frequency increases (more explosions per second) and you get the higher pitch sound or waaaaah, ie. the characteristic Ferrari wail.

    Additionally, noise is generated by the turbulent air flow from the air intake and exhaust systems. Engineers vary the diameter and length of the intake and exhaust systems so that standing wavesforms are created--this helps move the air through quickly, resulting in more air intake or better exhaust scavenging--this is how you get the term "tuned intake" and "tuned exhaust." These standing waves, or constant pulses, also contribute sound energy and form part of the engine's characteristic noise.
    The flat plane crank shaft is the key component. This allows for each bank to A) be in perfect ballance (primary) which allows B) each bank to have equal intervals of breathing which allows C) using harmonics in the pulse streams (intake and exhaust) to create more power.

    But Ferrari does not stop there:

    The intakes are short, straight, and direct, but the key component here is the throttles sitting in the exact center of the intake (plus velocity stack). This point has what is knonw as a pole in harmonic analysis terms. And having the throttle is the exact center of the intake allows the throttle to modulate the airflow without disrupting the harmonics. The single/dual throttle bodies of typical carrs cannot do this.

    To make use of the harmonic energy in the intake tracks, each bank is isolated in a helmholtz resonator that preserves the waves of the intake systems so that when a valve is ready to open, a high pressure wave is arriving at the back side of the valve just when the valve is set to open.

    Then on the exhaust side, each header is perfectly tuned to the RPM band where the engine make best power. In the power band, the header is tuned to have a negative wave arrive at the back side of the exhaust valve while it is still open. This negative pressure wave crosses the cylinder and arrives at the front side of the intake valves just as they open. The combined effects of the intake and exhaust resonance pulls fresh mixture into the cylinder even before the cylinder begins its downward journey.

    Finally, the cam is selected to work with the header and increase the wave effects in the intake system.

    In effect, its the whole package!

    But without the flat plane crank, about 50% of this harmonic energy could not be utilized because the pusle intervals would not line up in a harmonic way.

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    Exxxxellent, thanks man!

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    The materials used in all parts of the drivetrain and the way it's all attached to the car in general will also have some bearing.

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