A Dodge Viper and a Lexus LFA both use a V10 engine, but a Dodge Viper has a very “deep” sound, but a Lexus LFA has a very high pitched whining sound?
What makes a car like a muscle car like a Mustang or Viper have such a different sound than a car like a Lamborghini or Ferrari when they use the same kinds of engines?
In: Engineering
Generally the larger an engine is (displacement measured in volume) the lower the exhaust tone and the lower the rotational speed limit. The opposite is true as well. The faster an engine rotates, the more frequent the exhaust pulses which makes them seem higher in pitch.
The engine in the Viper is almost twice the displacement of the Lexus: 8.4L vs 4.8. The Viper’s engine has a redline of 6200 RPM and the LFA is 9000RPM.
Very simply, American performance engines tend to have bigger cylinders, resulting in a deeper note, and use a cross-plane crankshaft design. That results in the exhaust doesn’t come out in a smooth manner but instead comes out in pulses. This gives American performance engines like the V8 in the Mustang or the V10 in the Viper a deep, growling sound. By comparison, V8 in the Ferrari 458 or the V10 in the Lexus LFA have smaller cylinders, resulting in a higher note, and use a flat-plane design that results in a smooth, even exhaust note. The result is a higher-pitched whining sound.
Dodge viper has a V10 the size of phone booth with pistons the size of paint cans moving relatively slowly.
The LFAs V10 is the size of two shoeboxes with pistons the size of soda cans rotating at Jesus speeds.
Rpm. Bigger displacement engines with fewer cylinders have a lower rpm limit. Higher end cars with more cylinders but smaller displacement and rotating mass can rev much higher and produce that whine.
The car designer tunes the sound of the motor by changing the how the intake and exhaust pipes. Things like mufflers, baffles, resonators, etc. Also it has to do with the size of the motor, how many cylinders, in what order the cylinders fire and how high they rev. All these affect the sound of the motor and is something manufacturers pay a lot of attention to.
Also on modern sports cars tend to have fake engine noises being played over the car’s entertainment system. BMW does this, as does Chevy and Ford in their “performance” cars. I am sure other manufacturers do it as well.
So if you are driving something like a Dodge Challenger realize that it is probably a mp3 file you are hearing when you rev the motor up or hear it “rumbling”.
A bass drum and a snare drum have the same shape.
The size, depth, and tightness of the drum all have an impact on how it sounds.
Same thing for engines and the components attached to them. It’s all based on how the air moves as sound waves travel.
Here’s some great examples that explain it better than I could:
Flat plane vs cross plane:
V10 sound explained:
12 into 1 exhaust:
V12 with 12 into1 exhaust
gasoline engines harness the power of small “explosions” of gasoline and air to create movement. the order each cylinder “explodes” is different for different engines. the pipes the exhaust flows through where they all meet together can also be different lengths, so even if the cylinders all fired with equal time between each one, they come out of the exhaust with some closer together than others, which changes the sound
subaru wrx cars have traditionally had unequal length headers (the pipes that collect the exhaust together into one pipe to go out the back of your car), which made two cylinders’ exhaust pulses meet almost at the same time, which makes it sound more like a 2 or 3 cylinder engine
[unequal length example](https://www.youtube.com/shorts/ca0mk-xwABE). notice it doesnt’ sound smooth. it sounds choppy and you can hear the pulses
in the newest models, subaru switched to equal length headers like normal cars, and that made the iconic sound go away, so the exhaust sounds smooth like a normal engine. the rest of the engine is the same though. same order of “explosions”. same engine size (as the jdm market ones, before a subby fanboy comes to argue me on this lol). and yet, they sound completely different. [have a listen](https://www.youtube.com/watch?v=OnT5Smp_5W8)
also, sound travels in waves. you can think of those visualizations you’ve probably seen of sound waves. if someone claps their hands or some quick sharp loud noise happens, you can see a spike on the wave. each “explosion” of the engine is like a single pulse. [the higher pitch a sound, the more frequent those wave peaks are. the less frequent they are, the lower pitch the sound.](https://youtu.be/0j0rKNhmtIQ?si=bjolbzhMirFL4THT&t=255) so if you compare a 2 cylinder engine and a 10 cylinder engine, both having the same “size” per cylinder, the 10 cylinder has 5x more “explosions” when both engines spin at the same speed. this is what makes the exotic cars with v10 and v12 engines sound so high pitched. also, since i mentioned how frequently these “peaks” happen is what affects how high pitch a sound is, revving to a higher rpm also does this, so even if you only have 4 cylinders, like a sports bike (crotch rocket, whatever you prefer to call them), since they rev to 2-3x the max rpm that a normal car’s engine does, you get a much higher pitched sound. the size of the explosions also affects the pitch. the bigger, usually the deeper. smaller, higher pitch.
speaking of bikes, that’s another good real example. some motorcycles have 2 cylinders. those are usually called v-twins. (like a v-8, but with 2 cylinders) some bikes, usually japanese ones, have 4 cylinder engines like a small car. the v-twins usually have much larger cylinders, which means they have to have a lower max rpm. the sport bikes with 4 cylinder engines have tiny pistons and they have a very high max rpm (most can do like 10-13k+, depending on the bike. so the v-twin has bigger “explosions”, which means lower pitch, and it also has a lower rpm, so that also means lower pitch, and it has half the cylinders, so that also means lower pitch. that’s three things that all make it lower pitch. [have a listen](https://www.youtube.com/shorts/1fpv9nm1RVw). that’s a 650cc engine. now hear a 600cc engine (meaning nearly the same overall “size”), from the same brand (suzuki), but in a high-revving 4-cylinder. smaller cylinders (smaller “explosions”), twice the cylinders, and higher max rpm, all mean higher pitched sound. [have a listen](https://www.youtube.com/shorts/HlGS0dFFG6g).
it’s a lot of physics, so i overly simplified some things, which is why i put some words in “quotes” to let the armchair engineers know that i’m oversimplifying for the sake of ELI5
Engine works by making lots of booms. Engine sound comes mainly from pattern of booms. Those two engines are shaped slightly differently and make booms in different patterns QED.
*Booms spaced evenly make a “smooth” higher pitched sound while uneven booms make a rougher, deeper tone. Think Ferrari V8 vs Mustang V8 for another example.
Here is an amazing video explaining everything about car sounds, dont know if it will let me post a link, there was another video i think from Engineering Explained that he did a while ago that explains just the part of why V8 american muscle cars sound different than V8 european cars but i cannot find that video.
TLDR is:
American V engines normally have a cross—plane crankshaft, which results in their distinctive rumble at low revs, whereas European V engines normally have a flat-plane crankshaft, which results in a less distinctive low rev sound but a distinctive high rev scream.
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