What makes an engine sound good or bad?

Posted by cnvrtx3@reddit | askcarguys | View on Reddit | 32 comments

Why do some cars have really nice engine sounds and some sound like a tractor? I used to think that faster always sounds better, but I’m not sure if that’s the case. I used to drive a chevy kalos 1.2L NA around 80hp. It sounded absolutely horrible. Now I have an alfa romeo mito, pretty much the same power. It’s 1.4L NA 90hp, so still kinda slow, but it sounds so smooth and beautiful when you rev it. Both of these cars make around the same power, how come one sounds so good and the other one like garbage?

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yeeting_my_meat69@reddit

Opinions

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TiberiumBolognese@reddit

Individual throttle bodies.

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One_Evil_Monkey@reddit

"Good or bad" is totally subjective.

A Kalos... you mean a "Chevrolet Aveo" and now you think an Alfa-Romeo MiTo sounds good? You do know that the 1.4 Alfa isn't a naturally apsirated engine, right?

But "sounding good" literally depends... cam lobes, crankshaft degree, firing order... piston size,

A 270 degree v-twin Harley is annoying, a Ducati V2 with desmo valves has its own sound and can sound sweet. A Yamaha V twin with the same 270 crank tries like the Harley but not the same. A Kawasaki parallel twin with 180 degree crank is annoying to some folks. It has vibration.

A GM 60 degree V6 has an agressive sound. A Ford 300 inline six or GM 292 inline have their own as well.

A single cylinder engine has its own sound.

Four stroke, 2 stroke, Otto, Atkinson... all literally depends.

I think the Ford EcoBoost engines sound like crap on a cracker served with a side order hollow farts.

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PurpleSausage77@reddit

I want to know how badly they have to screw up to make something that sounds normally so good.

The new Mopar Hurricane I6 from what I’ve heard so far sounds absolutely terrible, didn’t think an I6 could sound bad, from Cummins to Toyota JZ and Nissan RB. BMW. Even the 4.2L GM had in the TrailBlazer, Envoy, etc. sounded decent.

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jtj5002@reddit

# of cylinders, firing order/interval, displacement, and rev.

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Shower-Haunting@reddit

Exhaust, induction, valve gear.

Some valves / lifters make tap like crazy if not well maintained.

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ZephyrStudios686@reddit

Literally all the characteristics of an engine lol.

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NoEmu5969@reddit

Then there’s V-angle, compression, firing order, bore:stroke, octane level, and emissions controls.

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TsunaTenzhen@reddit

Length of exhaust, number of bends, angle of bends, resonators, mufflers...

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easzy_slow@reddit

Cam and exhaust Big block or small block.

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Better-Credit6701@reddit

The LFA, by far the best sounding engine of all time, sent their intake manifold to Yamaha to produce the perfect sound. Then they did the same for the exhaust.

LFA

Not that great of a car, kind of ugly but I would sit and listen to it Rev for a couple of hours instead of the kind of musicals my wife enjoys.

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congteddymix@reddit

If your talking stock it’s mostly by how much a manufacturer puts into the NVH (Noise,Vibration, Harshness) engineering of a given engine or vehicle. You can have the exact same engine in two different cars and in one it feels/sounds like a noisy p.o.s and in another it’s quiet and smooth like it isn’t even running.

Great examples I can think of in my US based situation is the 2002 era Ford 4.6 v8 and how different it feels between a Mustang and Lincoln Continental.

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NoEmu5969@reddit

The US market Honda Goldwing even has varied bores on the exhaust manifold to make it sound like it’s running as poorly, like a Harley.

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Powerful_Tomato_1199@reddit

I feel like I'm the only person that hates snap crackle and pop in engines. Instead of a deep monstrous groan or roar.

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Bubbly-Pirate-3311@reddit

Literally every single thing has the potential to make it sound different.

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GrumpyDrum@reddit

Engine sound is as subjective as music taste, but in general a fuller sound with more depth is accepted as better sounding than a tinny, one dimensional sound. Hence why so many of the "best sounding cars" are 6+ cylinders. But as a few have said, the combinations of cylinder count, firing order, induction type, exhaust type and length, rpm range etc all contribute to how it sounds, and then it's just up to you whether you like it or not.

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Samsonlp@reddit

There are unpleasant frequencies. As with any sound, it has to do with harmonics, that is the shape and distances between various tubes. Resonators, mufflers, different shaped pipes all contribute. Think about design an instrument, if you don't like part of the sound you can change the shape, length or baffling on points to focus down frequencies and dampen others.

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Status-Importance-54@reddit

Nothing. I expect my car to be quit. Any engine noise is just that, noise. Of course there are different kinds of noises, but it's a bit like eating different kinds of shit. A long time I has to tolerate the noise because every car had it, but now - get in the car start it and just drive, without any noise or rattling like old tractors.

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MountainFace2774@reddit

Beauty is in the eye (ear) of the beholder. I have noticed the older I get, the more I just really like the sound of an engine running. It doesn't have to be "loud", but I do like a nice exhaust note.

Used to be, the only thing I cared for was a V8 or a Boxer (sigh, I was a WRX guy one time). Now I don't care as long as it's not a straight-piped clapped out Civic or Silverado.

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YozaSkywalker@reddit

High revs+ITBs

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Total-Improvement535@reddit

Scientifically speaking, how harmonized the engine is, which directly translates to how balanced the firings are in relation to crank rotation.

The closer/less degrees of rotation between firings, the more harmonized the pressure leaving the cylinders is going to be. A V8 has a more balanced sound than a 4 cylinder since it’s got twice the firings per crank revolution. A flat plane V8 is more harmonized than a cross plane V8 since you get one fire per bank back to back, leading to an even pressure in the exhaust system.

Subjectively speaking, it varies person to person. I enjoy the offset rumble of an old pushrod V8 like a Ford 302 and the sound of a modern performance 4 cylinder with a well tuned exhaust setup. I had a 3.5 V6 Lincoln MKZ that I chopped the mufflers off of and it sounded good to my ear, too.

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R2-Scotia@reddit

exhaust makrs a big difference

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ajm91730@reddit

Tons of science.

Or, in the case of Alfa Romeo, Italian witchcraft.

(Alfa makes configurations that shouldn't sound good, but do.)

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Thereelgerg@reddit

The size and shape of the exhaust valves, design of the cylinder head, various exhaust components, the speed at which the engine is turning, displacement, the number of cylinders. There are a ton of factors that contribute to how an engine sounds.

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eldredo_M@reddit

Most impressive engine I’ve ever heard was a straight pipe ‘60s racing corvette at a concours event. They fired it up and the ground literally shook. 😃

Impressive as it was, I like a much quieter and smoother rev. An early Honda Goldwing opposing four is pretty sweet.

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advmaxx@reddit

Chevy - sounds great.

Everything else - sounds like shit.

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jerik22@reddit

It all comes down to nostalgia 95% of the time 3% the engine and 2% the Exaust. I have a 1.8t vw 4 banger with a 5k custom turbo inlet pipe intercooler and intake paired with a 3k properly engineered Exaust and I get older car guys loving it until they find out it’s a 4 banger. They always ask if it’s a v6 first. So it’s just bias. Listen to the cars out there and make a judgement for your self, don’t just agree with all the other jabronies out there.

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