Exhaust sound

[Engineer]

Hi guys

I have a question about Porsche Carrera GT exhaust sound .
I know it's not an F1 question,but from previously asked questions,I've receved the most info right from this site .
So...Why/how does the Carrera GT exhaust system creates its specific sound.
Where is the key,how does it work?
I know ste sound is influenced by the intake manifold design or different tipes of filters (racing filters)and the exhaust system design.And that's it.This is where my knowlege stops.
So,if anyone knowsor has any useful info,I would be really gratefull for it.

Tnx for your answers,and I'm looking forward to read them

by by

[Giblet]

Fair question, but it has been posted in the wrong category. I will move it to 'Automotive news and technology subforum'.

Without going into too many details, as they are far too reaching, I will say that few people take into account much of what they are hearing is the intake sound. You are actually hearing the engine from 'both ends' when outside. An F1 driver mostly hears the intake when at speed, well unless you drive for Renault and the exhaust outlets are at the front of the car.

[Pandamasque]

What do you find so special about the Porsche Carrera GT sound?
Don't get me wrong, it sounds wonderful, but from what I've heard in my close encounters with this car it sounds not much different from other high revving naturally aspirated V10 engines (not that there are many that rev as high ).

[Caito]

For reference:
[youtube]http://www.youtube.com/watch?v=fdePhx9HVjo[/youtube]



It sounds great, but I don't think it's a "different" sound.

[hecti]

the noise from an engine is defined mainly by the number of cylinders it has. back in the day when you were allowed to have any type of engine configuration in f1, you could easily point out what type of engine a car had just by the noise it made. v12s shout, v10s are flat(like in the carrera gt and gallardo) and v8s "rumble". some things that affect the noise are induction and exhaust design, whether its carbs, itb's, or single tb, turbo or supercharged. The exhaust obviously has to muffle that noise for the car to be street legal, thats why the carrera gt has a muffled sound to it(compared to a v10 f1 car). engine displacement can also affect the noise (pitch) as well.

[Caito]

We could say not only number of cylinders, but the interval at which they fire is very important too.

You can have odd fire, even fire, and they make very different sounds.

With an exhaust you can equalize it, but the DNA of the sound resides mainly in the interval and amount of cylinders.

[Holm86]

I think the Carrera GT has a very specific sound.

Many of the other V10 supercars sounds more alike eachother but the Carrera has a unique sound in my ears. Very smooth yet very aggresive.

Its the only car i think sounds better with the stock exhaust than with an aftermarked one.

[hecti]

I think the Carrera GT has a very specific sound.

Many of the other V10 supercars sounds more alike eachother but the Carrera has a unique sound in my ears. Very smooth yet very aggresive.

Its the only car i think sounds better with the stock exhaust than with an aftermarked one.

I know what you mean, the first time i heard one i described it as a "coughing" noise. It for sure has a tuned exhaust and was designed to sound like it is, but it still sounds like a v10, flat and wailing.

[Formula None]

The Nissan VQ35 engine from the mid 00s was very melodic for some reason. It always surprised me to hear a 350z, infiniti g35, fx35 suv, etc., from that era due to it's distinct warbling sound. Anyone else notice that? I'm curious how they created it.

[Jersey Tom]

The Nissan VQ35 engine from the mid 00s was very melodic for some reason. It always surprised me to hear a 350z, infiniti g35, fx35 suv, etc., from that era due to it's distinct warbling sound. Anyone else notice that? I'm curious how they created it.

Yup. And I get to hear it every time I get in my car

[alelanza]

and v8s "rumble".

I'd say that's only true of crossplane V8s, hi revving flatplane ones such as the ones used in f1 sound more like 2 inline 4s stuck together

[Pandamasque]

and v8s "rumble".

I'd say that's only true of crossplane V8s, hi revving flatplane ones such as the ones used in f1 sound more like 2 inline 4s stuck together

Good point. Let me illustrate. This is Aston Martin V8 Vantage GT2.
Here's the sound with the earlier crossplane crank engine:
[youtube]http://www.youtube.com/watch?v=0ofFf8tv80k[/youtube]
This is the 'same' 4.5l V8 engine but with flatplane crank for 2011:
(jump to 2:00)
[youtube]http://www.youtube.com/watch?v=nyR0EC_ZaxU[/youtube]

... engine displacement can also affect the noise (pitch) as well.

I don't think that is correct, not for pitch anyway. I can't find it right now but I had a formula to calculate the rpm based on the pitch and the number of cylinders regardless of the displacement.

I think the Carrera GT has a very specific sound.

Many of the other V10 supercars sounds more alike eachother but the Carrera has a unique sound in my ears. Very smooth yet very aggresive.

The Lexus LFA sounds similar. That's the only thing I like about that car
[youtube]http://www.youtube.com/watch?v=u2UHaSRGBaY[/youtube]

[hecti]

i love v10s

[RH1300S]

Perhaps someone can confirm this......

It seems entirely logical to think that cam design and compression ratio also has an effect on exhaust note. I can imagine a valve being opened aggresively will have sound different to one being opened gently. Or perhaps a 'cammy' engine just produces a more violent bang.

We all know the difference between a car with a loud pipe but no tuning to one that is making power and a sensational sound.

[Caito]

At least in idle you can certainly hear a difference between cams.

With a lot of overlap you can hear the engine go:

pa pam pa pam pa pam

rather tan

pa pam pa pam

you get it.. right? jaja.