Distinct Sounds. How?

[McLaren]

Ok, this has been confusing me for a while, but my question is, how do companies like Porsche and Ferrari give their cars distinct sound?

What makes the Murcielago V12 roar, Enzo V12 sound so different?
How do companies like Porsche get their distinct engine sounds like when reving the car.

I also thought of Porsche's being reved having a more distinct sound than most companes.

How? How do these manufacturers keep their V8, V10, and V12 different from the others?

 

[Double_R]

Extensive work on exhaust notes.

 

[JNasty4G63]

Engine angle, firing order, exhaust length, engine type........those are all big factors. Take a Subaru WRX for example. The reason they sound so different is because the engine is a flat-4, not an inline 4. And, with the turbo mounted closer to the passenger side of the car, the exhaust pulses from the engine take different ammounts of time getting out the back of the car. Thus, they end up with that low, burbly rumble. Some say they sound like they're running on 3 cylinders.

The same goes for Porsche with their flat-6 engines. They use more conventional equal length exhaust manifolds, so they don't sound so bad. But, with the different engine configuration, it does have a little different sound.

The intake has a big factor as well. Most of the great Ferraris have a very distinct induction sound, mixed with a very sweetly tuned exhaust. And, many Ferrari and high performance V engines will use whats called a flat plane crank. The flat plane crank configuration, along with a slightly different firing order gives them a very distinct sound.

So, to answer your question, there are many factors in there that the company can change to get a different sound.

Hilg

 

[T5-R]

Or if you believed boy racers, all you need for a 'minted' sounding exhaust is a large bean can exhaust tip.

Weenie gud!

Hmm wonder if I can make my car sound like a Porsche, after all its got a Porsche engineered engine (a 1.2i ) Ahhh would be funny...

 

[///M-Spec]

Years ago, as JNasty already put it, the sound was simply a by-product of the engineering choices. Basic architecture and design of the engine dictated the sounds it would make. If you think about it, the sound an engine makes is simply a series of exhaust pulses which run along a narrow metal tube and the purely mechanical noises made by the reciporcating parts within the block-- combined with anything (if at all) that escapes from the intake tract.

These days, I believe almost all performance cars have exhaust sounds engineered into them. I remember reading when the water cooled 996 was introduced that Porsche actively worked to recreate the old air cooled sound that was distinctive of the 911. A lot of it was exhaust work, but I'm sure there was sound tuning made at every level in the development.

The Dodge SRT-10 engineers made the sipe pipes of the Viper an "H" pipe that connected in the middle so that you could hear all 10 cylinders, instead of just 5 on the old sidepipe models, just to avoid having the car sound like a UPS truck.

The BMW Z4 has a plastic resonator --a sub-woofer, if you will, that physically connects the intake manifold with firewall ahead of the dash, in order to "pipe in" engine noise because otherwise it wouldn't make it past the sound deadening in the passenger compartment.

But all in all, I think most sound tuning these days is done at the post-cat phase, within the muffler itself, though I'm sure there is plenty of header/downpipe/pre-cat work too.


M

 

[Duke]

Extensive work on exhaust notes.

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[McLaren]

Thanks JNasty and M-Spec.

I always wondered about this.
But it seem that all it takes os for the company to do a little work on the exhuast and engine, and bam. Authentic sound.

Thanks guys! 👍

 

[Iceman]

I think in a car magazine I read somwhere that car companies don't just work to get a distinc sound in their cars, they actually fine tune them with computers and sound equipment. I believe it was Porsche, but I'm not exactly sure. I imagine there are so many different ways to change the sound that it would be hard to pinpoint the exact reason why each has the sound it does.

 

[JNasty4G63]

Well, as M5 and I both described, now a days, its more a result of "MAKING" the engine sound a certain way, rather than just let it happen. Back in the day, when the designs of engines were a bit of a black art, you would see all sorts of designs and styles of engines. All of which would have a different sound. Then, as certain cars became more "known" for a certain sound, the company would try to get the new cars to still make that sound.

As M5 stated, when Porsche switched from the air-cooled engine to the water-cooled engine in the 996, they did a heavy ammount of work to get the exhaust and intake sound distinct and still have that "Porsche" feel.

Same goes for Subaru. Like I said earlier, the reason the boxer engines in a WRX sounds so funky compared to other engines is the fact that the header tubes are un-equal length. The exhaust pulses from each side of the car get from the heads to the turbo, and then out the car at different times. But, on the Spec-C car, they actually use an equal-length header on it, thus making it sound like every other 4-cyl car out there. That design can work better in some circumstances because of the "scavenging" effect on the exhaust. But either way, the Spec-C STi sounds nothing like a normal Suby because of it.

And, also like what M5 said, and similar to the Suby sounds, the design of a V-shape engine's exhaust is very distinct. On early Vipers, with the side pipes, many of the aftermarket exhaust solutions were just high flow units that didn't have an X-pipe. They would just have 2 banks of 5-cyls running off the engine, and then out the side of the car. Thats all well and good when stock. But not once you put an aftermarket exhaust on that has much louder sound and higher flow. The cars would end up sounding like they had real high strung 5-cyl engines in them. Not that good. Same goes for just about every V engine out there. They will almost always use some form of X-pipe to balance out the exhaust pulses to get the car sounding correct.

But overall, the sound of cars these days is all science. Back in the day, it was just the byproduct of innovative or unusual design. But now, with the computer simulation and ease of engineering processes, they can make a car sound pretty much how ever they want.

Hilg

 

[1X83Z]

It was ///M-Spec. I promise, I'm not that smart.

(I also couldn't care less about how an engine sounds from the passenger compartment)

 

[JNasty4G63]

CRAP, I borked that one. Is it me, or is there a lot of members on here with "M" based sn's??? I wasn't paying attention, my bad.

- side note, I also could care less about sound. I have some favs when it comes to automotive sounds, but as long as it works, I could care less what it sounds like. A guy I know has a really kick ass Civic hatch with a totally worked over motor. All motor, no turbo or anything. It sounds like a dirt bike from outside when he's on it, but damn if it isn't very quick. Works for me.

Hilg

 

[Super Jamie]

everything in an engine that the air flows past makes its exhaust note. from the airbox through the filter, inlet tract, throttle body, inlet manifold, runners, ports, valves, combustion chamber, bore and stroke, exhaust manifold and finally exhaust pipes, mufflers and tips

some of these things make more of a difference than others, for example you can get a more different note by changing exhaust pipes and mufflers than you can changing valve shapes, but everything will make a slight difference

some of what you hear is also induction noise, or how the engine sucks in air as well, which is primarily changed by modifying the system up to the throttle body

a turbocharger changes the note of an engine quite substantially as well, reducing noise like a muffler

no two engines of differing design sound the same because, even fitted with the same inlet and exhaust systems, the ports and combustion chambers (including piston swept volume) are different, and create different sound waves as the engine burns air fuel mixture

it's also the reason why some engines sound rubbish no matter what you do (n/a rb25de) and why some are hard to get to sound anything but tough (windsor v8)

 

[daggoth]

Great thread guys

This question has crossed my mind a few times and now I understand it all a bit better. Some members here are real petrol heads

Here in Portugal you see a lot of people change their exhaust pipes or punching a hole in the exhaust to make the car, if not better sounding, louder. I find that really really stupid

I personaly love the sound of my celica! If you rev up the engine a little there's a ffffhhhh blow sound that comes out through the exhaust. It seems the car is breathing, I LOVE it

 

[Double_R]

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It was a quick overview because as I watched on top gear as they talked about some ferrari. Most ferraris sound very similiar and have a very distinct sound even though many have very different engines. They do work on the exhaust etc to get it to make the sound that they want. Just how with organs you get different sounds according to their size. Happy now?

 

[Takumi Fujiwara]

Anyone ever listen to any engines with no exhaust whatsoever, IE just right out the exhaust ports? Personally, I'm partial to the sound of an N/A RX7 like that. Sounds like a 1920s Radial airplane engine.

 

[Super Jamie]

working on my mate's 13b bridgeport rx7, we had the mufflers off it and decided to start it to see what it sounded like, just dumping straight out the extractors. i can only describe it as the loudest thing i've ever heard, it sounded like a tractor clapping right next to my ear, it would have been pushing 150db or more. not enjoyable, but tough the car does 109db with mufflers. mine's 114db

a stupid friend of ours had a mazda 808 with a 12a in it, when he put the engine in, he started it with no exhaust manifold to see if it would run. it burnt the paint off the inside of the engine bay

 

[Quick_Nick]

It's interesting what most of you are saying. As Super Jamie explained, every part of the powertrain, from the intake all the way from the very tip of the tail pipe contributes to the sound. From what I understand the most distinctive aspect to determine how deep or high pitched the engine sounds is the bore & muffler diameter. Also the firing order & valve train type changes how rough the engine will sound. That's pretty much the most I know. Can someone explain how intake & engine configuration changes the sound? I don't really understand that yet.

 

[Takumi Fujiwara]

working on my mate's 13b bridgeport rx7, we had the mufflers off it and decided to start it to see what it sounded like, just dumping straight out the extractors. i can only describe it as the loudest thing i've ever heard, it sounded like a tractor clapping right next to my ear, it would have been pushing 150db or more. not enjoyable, but tough the car does 109db with mufflers. mine's 114db

a stupid friend of ours had a mazda 808 with a 12a in it, when he put the engine in, he started it with no exhaust manifold to see if it would run. it burnt the paint off the inside of the engine bay

Actually, ours caught on fire, too. Story was, we picked up the car cheap. It was a Turbo, but the turbo and its manifold blew. So my friend, the buyer, decides he's just gonna drive home with no manifold. It left a "Back to the Future" - style fire trail down the street before we had to put it out, about 10ft later.

 

[Emohawk]

Can someone explain how intake & engine configuration changes the sound? I don't really understand that yet.

Intake noises come from the shape of the intake piping and how air swirls around in it while being sucked toward the valves. Because of this, intake noises are more noticeable higher in the RPM range, and maybe not at all in normal driving.
As to why a flat 4 sounds so different from an inline 4 (for example), I'd like to know myself.

 

[JNasty4G63]

.....As to why a flat 4 sounds so different from an inline 4 (for example), I'd like to know myself.

Well, its not really the engine configuration that makes the sound different. Its more in the exhaust manifold.

In a conventional inline engine, exhaust pulses exit out the head and into the exhaust manifold. But, the shape of most inline engine exhaust manifolds make all of the pulses mix together very evenly and then exit the tailpipe sounding very normal. The pulse from one cylinders exhaust valve opening slots right into the negative area created by another cylinders exhaust valve closing. Even flow, smooth sound.

But, on some flat engines, mostly Subaru turbos, the manifolds and firing order are a bit different. On a WRX the turbo is mounted above the engine, over on the passenger side of the car. So, when the exhaust pulses come out the head and into the manifolds, the positive pulses from one side of the engine reach the collector area earlier than the negative pulses from the other side. Thus, they don't mix real well, and actually overlap a bit. Some pulses cancel each other out, but not all. Thats why some Suby's have that burble.

That design isn't real good for flow because of the overlap, and causes a bit of backpressure. But, given that the turbo is a much higher source of back pressure, its no big deal for your average daily driver. Some back pressure isn't bad. But, for higher spec cars, such as most Porsches, they will use an equal length exhaust manifold to reduce back pressure. They are a bit more intricate and harder to design, but for those levels of cars its worth it. And, actually the Impreza STi Spec-C uses an equal length design as well. Its the highest level of all the Imprezas, so they went all out with it. So, it actually doesn't have that normal Suby sound.

Hope that makes sense. Its kind of weird to describe.

Hilg

 

[Emohawk]

Perfect sense, thanks. Makes me want to go read more about manifold design