what makes different engines sound well different

[KnifeEdge_2K1]

why does an I4 sound distinctively different to a boxer 4
a v6 to an i6 ??

does a v8 sound with a cross plane sound different from a flat plane v8 ??

it's to do with the timing of the opening and closing of valves or the speed at which the exhaust is being pulled out of the cylinders ??

i'm thinking its a combination of these factors but am unsure of this

also am i right to assume that the size, length, and merges in a header affect the sound ??

[taz_rocks_miami]

why does an I4 sound distinctively different to a boxer 4
a v6 to an i6 ??

does a v8 sound with a cross plane sound different from a flat plane v8 ??

it's to do with the timing of the opening and closing of valves or the speed at which the exhaust is being pulled out of the cylinders ??

i'm thinking its a combination of these factors but am unsure of this

also am i right to assume that the size, length, and merges in a header affect the sound ??

I've asked myself this question in the past. I think it has to do with the factors you have already mentioned. Displacement, configuration, number of cylinders, camshaft duration ect.

Too bad Matra et Alpine isn't around anymore. He could have given a good technical explanation to this.

[fpv_gtho]

Firing order has a huge effect as it changes the exhaust pulses. That'd be a big reason why boxer's sound so different

Cylinder count obviously would too. An engine with more cylinders probably wouldnt sound as lumpy as one with less as theres more exhaust noise. If you think that 6's and 12's manage their firing order 60 degrees apart, and 4's and 8's split them 90 degrees apart, you can see how both can produce such different exhaust notes

Exhaust layout too plays an effect, such as if theres exhaust manifolds or extractors, single pipe, twin pipe, twin pipe with crossover etc.

[2ndclasscitizen]

I have something on it in the back of an old issue of MOTOR, I'll see if I can dig it up.

EDIT: Damn, no luck. Must've been in the pile I took to work.

[KnifeEdge_2K1]

why isnt matra around anymore ?

[fpv_gtho]

I dont know what the official word is, plenty of rumours however.

[baddabang]

I dont know what the official word is, plenty of rumours however.

Hes on MSN why dosent somebody ask him?

[NSXType-R]

My dad told me once that the intake manifold and exhaust system has a big impact on the noise of the engine. Obviously the displacement and the configuration of the engine does too.

[LotusLocost]

IIRC an easy scientiffic formula for sound is: sound = air in movement.
So the more air thats moving, the louder the sound.
From personal expirience, the sound is always depending on the type of aspiration. Carbs (and number of carbs). Fuel injection..or any type of forced induction..
And also the length of the exhaust is a factor to concider..
And compression... more (higher) compresion.. noisier engien..

[KnifeEdge_2K1]

um dude ... amplitude is unrelated to frequency/wavelength, im not talking about how loud it is
big difference

the displacement would most likely affect the amplitude as the amount of air is being changed and thus the strength of each pulse is stronger, same goes for a forced induction engine, however the turbo and s/c themselves have disctinct sounds and should be left for another discussion

[h00t_h00t]

V and I engines sound different because Vs usually have two seperate exhaust systems whereas an I has one.

Also the manufacturer may have just wanted the car to sound like that, for example a V8 Merc sounds alot different to a V8 TVR.

[Quiggs]

It's all in the airflow...

Between the intake (airbox and tubing), intake manifold, head, exhaust manifold, exhaust. Different diameters and shapes will produce different sounds.

[fpv_gtho]

V and I engines sound different because Vs usually have two seperate exhaust systems whereas an I has one.

Many V engines go to a single pipe though

[NAASBC355]

AIR put simply...volume, velocity, and less so pipe size. Engines are air pumps, you are listening to them pump air, it's under a lot of pressure so it pops when released, thats all nothing too it.

~Couch

[F1_Master]

See my thread at GTPlanet for a couple answers.
http://www.gtplanet.net/forum/showthread.php?t=61114