Why Do Car Engines Sound Different?

LeeAnn Shattuck (00:01.582)
Hey everyone, welcome back to The Straight Shift I had a birthday a few weeks ago and no, am not gonna tell you how old I am, but my husband asked what I wanted for my birthday and I am notoriously difficult to buy gifts for. So back in March, I lost my older cat, Georgia to cancer, but I thought I might be ready to get another cat and I wanted to get a kitten because my older cat, Callie, that I still have is a bit, shall we say,
“spicy”, so it’s usually easier to introduce a kitten. So when I broached this topic with my husband, you know on the morning of my birthday, so he couldn’t possibly say no his response was “well , isn’t it better to get two kittens so that they can grow up together and bond? So we got two kittens! We came home with Belle and Burt. Belle is a little brown tabby She’s about four to five months old and Burt is this huge black and white floof monster
He’s a tuxedo Norwegian forest cat. And even though he’s only six months old, he is going to get even bigger and he’s a shameless love sponge. So why am I talking about kittens on a podcast about cars? People with kittens and cats in general tend to describe the way their cat purrs, like it’s a motor, like a car’s engine. And some people even go so far as to say their cat sounds like a specific type of vehicle, like a diesel or a Harley. Of course, my husband,
and I are total nerds because I’m The Car Chick and he is both a master certified mechanic and a sound engineer. So as you can imagine, we tend to get a little more specific about what car engines our cats sound like. Little Belle has a very quiet, smooth purr. She’s more like a refined inline four cylinder engine. Bert, on the other hand,
has this deep rumbly purr that sounds like an American V8 with a crossplane crankshaft. So what does that mean? I wanted to use… So What does that even mean? And now how do car people, motorheads like us, even tell cars apart solely by the way they sound? Part of it is because we’re nerds, but there is a lot of physics behind it.
LeeAnn Shattuck (02:21.324)
So without getting too nerdy, I promise there will not be any math involved, I want to use this episode to explain why different engines and cars sound so different. I’ll also talk about some of the best sounding and worst sounding cars of all time. So let’s get into it.
LeeAnn Shattuck (02:44.374)
It’s absolutely amazing the diverse sounds of all the different car engines that are out there. And even the variations between sounds in cars that have the same engine but still sound completely different. Again, part of that is just physics, but it’s also a very intentional application of the physics by the car makers.

Car manufacturers spend millions of dollars developing unique sounds that become associated with their brands. For car people, we know the sounds of cars. There are certain car sounds that we just absolutely love. And part of that is what we grew up with, what we’re used to, and quite frankly, just what sounds awesome. We tend to be loyal to the brands that we like the sound of.

And car manufacturers understand that psychological link between sound and emotion. And they use that to create loyalty to their brand. Because if they have a great sounding car, that can create brand loyalty. Similarly, if they have a car that sounds like crap, that’s going to hurt their sales and potentially hurt their brand. So let’s talk about what determines a sound that a car makes. Before we jump into that, we need to first just talk about what is sound?
Very simply, sound is waves of different pressure traveling through the air into our ears, which our brain interprets as sound. How fast those waves oscillate determines the frequency, and that frequency determines the pitch of a car’s sound. A slower wave is a lower pitch, while a faster wave produces a higher pitch.
And then the evenness of that wave determines whether the sound is smooth and clean or if it’s more guttural and angry. And that applies to car engines. The first factor that determines the sound of a car engine is just the number of cylinders. When we talk about the number of cylinders in a car engine, like it’s a V6 or it’s an inline four, it’s a V8, we’re usually talking about how that number of cylinders impacts the car’s performance and also its fuel efficiency.
LeeAnn Shattuck (04:56.78)
And there is almost always an inverse relationship between performance and fuel economy, but that’s a different sound. That’s a different podcast, but it also affects the sound. So now we need to do a really quick lesson about internal combustion engines. Each cylinder in an internal combustion engine contains a piston, which is like a big metal fist that moves up and down inside the cylinder. Those pistons compress the air fuel mixture, which ignites and creates the combustion that then powers the engine.
The pistons also transfer the force of that combustion to the crankshaft, which then powers the rest of the engine. That’s what makes the car go forward, or if you’re in reverse, go backwards. The pistons also push the hot gases from that burned fuel out of the cylinder and into the exhaust system. So the sound that a car engine makes is the sound of that internal combustion, the sound of the explosions sending pulses of pressurized air through the exhaust. So, yeah.
It’s basically a fart. And it’s why electric cars are essentially silent. There’s no combustion. Well, until they catch on fire anyway. But again, that’s topic for a future episode. In general, the more cylinders that an engine has, the more explosions per minute. And the more explosions per minute, than per second, the smoother and deeper the sound. This is why an Aston Martin sounds better than a Ford Fiesta. And yes, there is a direct relationship between sound quality and price tag.
But it’s not just the number of cylinders in the engine. It’s also how they’re arranged, as well as the order in which those cylinders fire and how often they fire. The engine layout that most people are familiar with is the V layout, where you have two rows of cylinders forming a V shape. So for example, with a V8, you have four cylinders on one side and four cylinders on the other side of the V. The other most common layout is the inline, where all the cylinders are just lined up in one row along the crankshaft.
The most common of those is the inline four. They also have inline sixes that BMW is known for. There aren’t any inline eights anymore because when you line up eight cylinders, it gets kind of long and we don’t have that much room under the hood anymore, but there are some old vintage cars that have that configuration that are pretty cool looking. Well, finally, there’s what’s called a flat or boxer configuration where the cylinders are placed on opposite sides of a central crankshaft. So imagine a V engine
LeeAnn Shattuck (07:23.982)
and then you flatten out the V and you have the cylinders just on either side of that boxer configuration of that crankshaft. The cylinders are typically numbered sequentially from the front of the engine to the back of the engine bay. So in an inline four, that’s really easy. It’s one, two, three, four. On a V engine, they either number them sequentially down the left side and then back down the right side. This is what the Europeans do. This is what Ford does. And that’s the same for the boxer engines.
Or they might do them alternating odds down the left and evens down the right. That’s what GM and Chrysler do. But it’s the specific sequence in which those cylinders fire that creates that distinct rhythm and pressure of pulses that influence the overall engine tone. A common firing order, for example, for a four-cylinder engine is 1, 3, 4, 2, meaning cylinder 1 fires, then 3, then 2, then 4.

and that helps keep the engine balanced. So the firing order also determines how balanced that engine is. Now common firing order for an eight cylinder say is 1-8-4-3-6-5-7-2. That’s a firing order that’s very common in GM engines like a Chevy V8. That is what is called the firing order. What order do those cylinders fire in from one through however many cylinders are in that engine? The firing
interval indicates the time between each cylinder firing. So if the cylinders fire at evenly spaced intervals, the sound is smoother and more consistent. It has less vibration. The cylinders fire at irregular intervals. The engine can sound a little more erratic or lumpy due to those uneven pressure pulses. But different manufacturers use different firing orders and different intervals for their engines. And that’s just one reason that, a Ford engine sounds completely different
than a GM engine, even if those engines are both, say, a V8. Then there’s a motorcycle engine, and if you’ve ever heard a V-twin engine like a Harley Davidson, they have this very distinct potato, potato, potato sound due to that uneven firing interval of just the two cylinders. And because it’s only two cylinders, it’s very pronounced. That can be very annoying. Potato, potato, potato.
LeeAnn Shattuck (09:45.528)
When you get a V8, even if it’s uneven, because you have more of them, they kind of smooth each other out and you get a little more of a rumbly sound that we like.
The design of the crankshaft itself and how the pistons connect to it also affects that rhythm, especially on a V engine. So the two main crankshaft designs on a V engine are the crossplane and the flat plane. Now I am not going to get into the engineering details of those designs. It’s better to see that in an animation for it to make sense. So I’m going to link a really good YouTube video in the description below that if you want to go to that level deep dive nerd,
you can go for it. It’s a really good video and explains it well. I’m just going to talk about how those different designs affect the engine sound. A crossplane crank engine produces a deeper rumbling sound that’s usually associated with American muscle cars. The American manufacturers, the classic standard American V8, was a crossplane crankshaft. We don’t have a lot of V8s anymore, unfortunately, but we still do. It tends to be a crossplane V8 in America. There are some exceptions. The
Corvettes for a while had a flat plane, but for the most part, if you hear an American muscle car that has a V8 engine, it’s probably a cross plane V8. And that gives them that very distinctive, rumbly sound that we associate with the American muscle cars. Like this Mustang GT.

This type of design accounts for, nevermind, delete that. In contrast, a flat plane crank engine has a sharper screaming sound that says, out of my way! And those are usually associated with the high-end European sports cars like the Ferrari and the Porsche, like this sounding Ferrari. Ooh, yeah. I personally love both sounds and I’ve had both types of cars, not a Ferrari, I have not had a Ferrari, I wish I’d had a Ferrari, but I’ve had Mustangs.
LeeAnn Shattuck (11:43.53)
American muscle cars, I’ve had American trucks, and I’ve had Porsches, so I’ve had the gambit between American muscle and European sports cars. But there are few sounds, honestly, that are more satisfying than that rumble of an American crossplane V8. Like Burt!
LeeAnn Shattuck (12:05.346)
The engine and the crankshaft designs are not the only thing that determines how a car sounds. Another big piece is the exhaust system. The job of the vehicle’s exhaust system is to collect the gases produced by the engine during combustion, many of which are toxic. It cleans them up, removing those toxic emissions, and then moves them out of the vehicle and into the atmosphere.
Different exhaust systems sound different because of variations in size and shape and just the design of their various pipes and other components. When it comes to pipe diameter, larger pipes tend to produce a deeper, more rumble-like sound. Why smaller pipes create a higher pitch sound. And the length of the pipes makes a difference. Shorter pipes can lead to a more aggressive throaty sound, while longer pipes can smooth out those waves and create a smoother tone.
And most cars have mufflers. The muffler with its internal chambers and baffles significantly reduces how those gases and those air pulses flow and resonate, creating distinct sound qualities. And that’s often referred to as the exhaust note. You’ll often hear people talk about how a car sounds in terms of music that a car’s engine and its exhaust system
are like a wind instrument, and they do actually function in a similar way for those of you who are into music. It’s also why race cars are so dang loud because they usually don’t have mufflers and we just run straight pipes right out, usually even the side of the car. We don’t even run them out of the back of the car, and that’s why they’re so dang loud and don’t always sound good when it’s lower level racing. Lemons cars don’t sound like F1 cars, but that’s okay. Speaking of which,

Let’s talk a little bit about the best and worst sounding cars of all time, now that you have a little bit better understanding of why different cars sound so different. As I said earlier, car manufacturers spend millions of dollars developing unique sounds for their various engines. Sometimes they get it right, sometimes they don’t. Every motorhead, whether a casual motorhead or a
LeeAnn Shattuck (14:18.478)
hardcore motorhead like me and my husband, we all gotta have our favorites when it comes to car sounds. But if there’s a general consensus across the car enthusiast world for what the best sounding car of all time is, it’s the Lexus LFA. The LFA was a two-door supercar from Lexus that produced 552 horsepower out of a 4.8 liter V8 engine.
Lexus spent 10 years developing the LFA, yet they only produced and 500 units over a two-year span between 2010 and 2012. So it’s a very rare vehicle, but wow, what an incredible performance machine. The Japanese are known for their perfection. They don’t tend to invent anything new, but they study what’s been done before and they find ways to perfect it.
They get very, very specific with their engineering and the sound of the LFA. my God. Take a listen.
Wow. Lexus assembled a special acoustic team specifically for the LFA project. Their sole job was to ensure that the exhaust note of the LFA was unlike any other car on the road ever. They composed actually a soundtrack. That’s how they approached this. They optimized the sounds at
each RPM to enhance that sensation of the speed and acceleration, the whole driving experience. And they also piped that sound specifically into the cabin through three special sound channels, one underneath the dash and two overhead to create the surround sound effect so that the driver and the lucky passenger
LeeAnn Shattuck (16:16.846)
could enjoy this same experience as much as everybody standing outside listening to the car while you’re driving it. It’s just over engineering, I think, its absolute best. And they totally nailed it. Unfortunately, they lost their ass in terms of money on the project, but they really set their place in history because this was the first time that Toyota, which is what Lexus is, had really tried to make a supercar. And you know, anything worth doing.

is worth overdoing. Let’s listen to that again. That is music to my ears. Okay, on to the potentially worst sounding engines. Just in general, most people find diesel engines to sound terrible. It’s just because they’re louder than regular gasoline engines and that can make them a little bit more annoying. Diesel engines sound different because of the high compression and sudden ignition
of the fuel during combustion. A diesel engine does not use a spark plug to create that little bit of fire to ignite the air fuel. Diesel’s do not have spark plugs. Instead, a diesel engine uses super compressed air. And when you compress that air, it gets really, really hot. Then it injects the fuel into that compressed air and it spontaneously ignites. And that results in this loud clattering sound that’s referred to as the diesel clatter.
It’s not the nicest sound in the automotive world, but it is very distinctive. And let’s face it, the job of a diesel engine is to work. It’s not to sound sexy. It’s not to sound smooth. Diesels do a job. They pull heavy things. They do that heavy duty work. So they’re allowed to have a little more of a rough sound. It is what it is. And some people love a good diesel sound because they do associate it with everything that a good diesel engine can accomplish.
and how long it can last if you take care of it. Of the gas engines, in the car enthusiast community, the Nissan VQ Series engine, that’s a 3.5 liter V6 that is known for its high level of fuel efficiency while still maintaining really good performance and high horsepower, also reducing tailpipe emissions. It’s honestly a phenomenal engine. It’s great, great engineering. And both Nissan and Infiniti have used that engine across
LeeAnn Shattuck (18:45.322)
a lot of their different models over many years. It’s a Nissan engine and it’s most associated with the Nissan Z sports cars and the Infiniti G35. I had one of those. It really is an amazing engine and it’s been reliable. But some people say it sounds kind of tinny or buzzy or nasally. Not a sound that we car enthusiasts like to associate with a powerful engine.
And part of that is the stock exhaust as well. We want something that sounds a little more deeper, a little more aggressive. You know, if it can’t sound like a Ferrari, then it needs to sound a little more aggressive and guttural. We don’t like this buzzy, nasally sound, so let’s take a listen.
Yeah, so that’s why many people who buy the Nissan Z change out the exhaust. With varying results, sometimes they sound amazing with aftermarket exhaust, and sometimes they actually sound worse. Just depends on how much money the owner had to spend on the new exhaust system. There are a few things worse sounding than a cheap exhaust. Which brings me to any four-cylinder engine with a cheap exhaust.

These things are usually put on by teenage boys and young men for the sole purpose of making the car louder. But they’re doing it on a budget, which I get. I respect that. But honestly, it often sounds like crap. Industry experts frequently refer to it as a wet fart, hence why those exhausts are called fart cans. Let’s take a listen. Yeah, not my favorite thing, but you hey, that’s what you like.
No judgment. Because while a car sounds good or car sounds bad, it’s very subjective. It’s whatever you like. So what is your favorite car engine sound? Let me know in the comments or connect with me on social media. And you can also go there to see pictures of Bert and Bell if you want to see those, if you’re not watching the YouTube version of this podcast. But speaking of which, please subscribe to the show if you haven’t done so and share it with your community.
LeeAnn Shattuck (20:53.58)
I also have an online car buying course now, the No BS Guide to Buying a Car, your inside track to getting the best deal. So if you think your car sounds like crap and you want a new one, you can grab that online course and get the benefit of all of my knowledge and experience and the methodology that I use when I’m buying cars for my private clients. You can find that on my website, thecarchick.com, or you can go to it directly at carbuyingcourse.com, and both of those links are in the description below.
Thanks so much for tuning in. got another great episode coming up next week because I am headed to the Charlotte Auto Show and I am going to give you the scoop on all of the new makes and models that have either just come out or are coming out soon. And I’ll tell you what my favorite picks are, what I didn’t like, and of course my infamous WTF award. Until next week, folks, drive safely. I’m out of here.