Does Ferrari tune the sound of thier motors?

Muffler tuning is a big task in the development of any car, depending on the product's image and market, etc. In the end, it's always signed off on by a group of decision-makers listening to a car. You can rest assured that Ferrari and whoever their current exhaust supplier is sweats the sound of the exhaust.
Likewise, manufacturers are always concerned with the overall sound coming from under the hood, too. That's why you see so many more resonators hanging off the intake plumbing of cars these days, accessories mouted directly to engine blocks and ribbing on brackets. Here the goal is usually just the absolute minimizing of noise within cost constraints.

 

Yes they do.

Porsche (and I'm sure Ferrari and other makers of sportscar too) have a department in Weissach, specialised in accoustics, to make the car sound "right" both from the outside of the car and from the inside.

/Peter

 

Indeed they do. In one of the latest yearbooks, there were pictures of Ferrari co-workers and some info of their daily job. I recall one of these coworkers was busy with exhaust sounds...

 

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.

 

In a nutshell, Ferrari V8s have a flat crank, which gives them their sound. I can't speak about the 12 cylinder engines.

 

That was a great explanation, F40Lover!

I'd love to find something similar that deals with how and why the classic Columbo V-12 sounds so special.

 

WOW! Very informative. I have often wondered why cars sound the way that they do. I did not realize that the engineers spent so much time tuning, nor did I know that the sound energy generated actually has an effect on intake/exhaust flow. Fascinating!!!

 

Great info there F40Lover............

 

Indeed! F40Lover's post makes me want to take an engine apart and see how it all works.

F40Lover, do you know the differences between say Ferrari's and Porsche's sound producing techniques? Lambo also has a very distinct note, but very close to Ferrari's.


Forza,


Cavallini

 

I will look into the Porsche engine and see what I can 'hear". I have always been able to simply listen to a engine and get a feeling by the sound "where" on the track it will preform the best. Since the advent of computers it is difficult to determine that since the computer can control the lean or rich-ness of the engine at idle which changes the sounds created within the intake and exhaust systems. My favorite is the 512 with Tubi. Nothing beats a flat crank sound. I once had a 327 Chev V8 built with a flat crank for stock car racing and after 2 races they outlawed my car, not because it won races but because it was SO LOUD that the fans could not hear the track announcer!!

 

The TR 12-cyl engine does not have a flat crank, but it does have alternate-bank-firing (which is the important characteristic -- not the shape of the crank + block geometry need to achieve it).

 

Great bit of technical info, F40lover, I have always liked reading/learning about the technical side of things, I might never use the info, but it's cool to know anyway. Have been looking for a good book about engine design, any thoughts??

 

There are two references referenced by "all" engineers in industry:
_The_Internal_Combustion_Engine_In_Theory_and_Practice_, Charles Fayette Taylor (2 Vols, approx 500 & 600 pages respectively)
_Internal_Combustion_Engine_Fundamentals_, John B. Heywood, Approx 900 pages

The Heywood book is probably the most common reference book in engine engineering offices (I'd say 2nd place is the Bosch Automotive Handbook).
It's not light reading, but engine design isn't easy! I'm sure you can get these from Amazon, etc, or through sae.org.

Enjoy! Don't forget to set your alarm clock!

 

I guess you never heard a ported Racing Beat RX7 at 8000 rpms next to you? It makes a statement. Same thing w/ the Ferrari.

http://members.cardomain.com/snapshot1

 

I don't mean to be rude, but making non Wankers listen to that without adequate mufflers is... rude! LOL

Err, make that Wankelers!

 

I love the sound of Ferraris, especially the 512S/M and 312 PB, but the most impressive to me has to be the BRM V16. Anybody who bought the book by Nick Mason "Into the Red" with the CD? They know what I mean! ;-)

btw a large part of the sound is affected by the exhaust design (because it is the loudest part). Take for example the Subaru flat four (boxer). Standard it has this distinctive throbbing sound, but in WRC form it has equal length exhaust manifold and it looses that sound.

btw is it true that the 360 Modena has a valve in the exhaust pipe?

 

These books are not "armchair" books. You require a loveseat....one for you and the other for the books!

This is the meat and potatoes of engine design. Now with faster and better 3D and 4D software we can design engines on the computer, "run them" and make changes without waiting for months for development time. This is very high tech stuff and it takes a whole team of people inputng the data to get results.

There is nothing like the sound of an engine or wheel dyno to "light the fire within" the human body. A highly tuned racing engine is music to many peoples ears.

I heard a new Maserati today, awesome throaty sound at low end. Now if a F430 would only stop buy so we can do a sound check.........

 

I was in Maranello earlier this year (sept 20th) and saw 2 F430s running at the Fiorano test track. The car sounds wonderful. The exhaust note is similar to the Challenge Stradale with some of the zing of a 355 exhaust note.

The F430 cruising at slow speeds between the mfg floor and the track on the access roads didnt sound as deep as a stock 360 Ansa exhaust but it had a great burbling sound. I was drooling!! I cant wait to hear one again.

Cheers,

 

The M3 CSL also sounds amazing.