Another exhaust thread.

[PurpleCherokee]

a lot of people have answered your question more than once. go back and read it, its not complicated.

Where? Nobody has explained which characteristics cause certain tones.

Go back and read it, it's not complicated.

 

[igotanxj]

I didnt think I had to spell it out for you...

A Porsche motor, GT3 included, is a flat 6. Meaning it's like a V-6 but completely flat and opposite of each other. Where as the 4.0 is an inline 6. Also, 219 CI vs. 242 on the Jeep. The lighter, shorter stroke allows it to rev QUICKLY and build better power for it's application. The 4.0 creates more torque with it's longer stroke. You'll never get the 4.0 to sound like any other "supercar" motor.

That motor has 4 valves per cylinder and is generally tuned to rev high. The 4.0 is tuned for low end torque and has 2 valves per cylinder.

If you ask me, they sound different because of the exhaust ports, valve configuration, valve lift and duration, exhaust layout etc...

The jeep motor sounds like a tractor, you'll never get it to sound like an M3

I had a nice long reply and then it asked me to log in again and then it was lost--bs.
Inline 6s do have a unique sound and I do hear similarities in mine w/ the bmw i-6 w/ aftermarket exhaust(ss, b&b, borla). Port size and shape play a role as does the exhaust system. I didn't get a chance to hear the difference of my head by itself after the p&p(it was installed same time as stroker), but I'm sure it's contributed. Those boxers(porsche and subi) have a unique sound of their own and of course the porsche with its rear engine has short pipes, so that'd be difficult to reproduce. Anyhow, I'm sure there are exhaust gurus out there that can make your vehicle sound a variety of ways(louder, quieter, mellow, raspy, deeper, etc). While on the topic, I'll be shopping for a 95 avus blue m3 come springtime.

There's so many variables, valve size/layout, displacement, compression ratio, layout, engine block material (yes it makes a difference), cylinder head port sizes. That doesn't even take into account header design, pipe diameter and length.

GM Spent millions trying to get the new GTO's to sound like the 65'/66' GTO's when they were first coming into production. That should tell you there is much involved.

don't forget that even minute changes in your camshaft/shafts (depending on what engine we are referring to) can change the sound as well, something as small as a 2* change in the LSA can tweak the sound, not to mention adding lift, duration and all that.

There are so many different things involved in the sound an engine makes that you will never be able to match two different engines, even if they are the same size but made by different people. ex: my moms Chrysler Pacifica sounds nothing like my dads 350z even though they are both 3.5 V6s.

The easiest way for you to achieve sound on your car is muffler, header, and head work. other then that your just getting into a money pit worth of work, all just to sound like a Porsche.

good luck

I don't see any reason that this thread should still be open...

 

[IslanderOffRoad]

Where? Nobody has explained which characteristics cause certain tones.

Go back and read it, it's not complicated.

Go hire an acoustical engineer.

 

[Monkey55]

Go ahead and show me when I was acting like a dick.

Just take a look at all of your posts. People try to give you feedback, but you dismiss it and only listen to what you want to hear.

This is why you are in contention for nomination of the year.


E

 

[juniorXJ]

study sound. how it works, why it works, what makes it, and what it does (its accualy really interesting.) but to answer the question i would have to say it has to be the muffler that most effects the way any certain engine sounds.

 

[PurpleCherokee]

I didnt think I had to spell it out for you...





I don't see any reason that this thread should still be open...

Ok, so far I have...
"219 CI vs. 242 on the Jeep"
-Ok, so CI's affect how the motor sounds... who woulda thought of that one?

"A Porsche motor, GT3 included, is a flat 6"
-True, but there are plenty of "v" arranged supercars with the same sound.
Doesn't say much.

"If you ask me, they sound different because of the exhaust ports, valve configuration, valve lift and duration, exhaust layout etc..."
-I'm looking for somethin a LITTLE bit more conclusive than "if you ask me"

"Port size and shape play a role as does the exhaust system"
-That on the right track, however, I'm still looking for references and/or empirical, more comprehensive data.

"There's so many variables, valve size/layout, displacement, compression ratio, layout, engine block material (yes it makes a difference), cylinder head port sizes. That doesn't even take into account header design, pipe diameter and length"
-That basically reiterates my question. Still looking for some empirical data.

"minute changes in your camshaft/shafts"
-Again, good and true info, but no specific info.

I want to make clear that in no way shape or form am I ridiculing those above who have tried to provide insight! The bottom line is that these people have actually tried do HELP me, not just post in order to act like a tool like igotanxj.

 

[PurpleCherokee]

study sound. how it works, why it works, what makes it, and what it does (its accualy really interesting.) but to answer the question i would have to say it has to be the muffler that most effects the way any certain engine sounds.

Thank you very much for actually trying to help rather than ridicule. And you're right but there are SOOOOO many variables in an ICE or this question would be a lot easier.

 

[Monkey55]

Ok, so far I have...


I want to make clear that in no way shape or form am I ridiculing those above who have tried to provide insight! The bottom line is that these people have actually tried do HELP me, not just post in order to act like a tool like igotanxj.

Now you're using your brain by piecing together helpful information that people have posted.

I don't think igotanxj was trying to ridicule you. I think he was pointing out all of the stuff people posted that you glossed over.

If you are looking for exact specs, you may want to get FSMs for both engines and compare them. You then can take the information people posted and compare it the specs. I think you'll have a greater understanding of what you are seeking.

E

 

[igotanxj]

Play nice...

While we may have disagreements, there's no reason for personal attacks, name-calling, or other misbehaviour - this ain't Pirate.

(Oh - and "sound" isn't the same thing as "acoustical energy" - and a muffler and exhaust system - and an intake, to a limited degree - are designed to make effective use of "acoustical energy" to achieve a clearly-defined goal: the filling and emptying of a cylinder of varying volume.)

-Ed.

 

[crazyjim]

Wow... If you don't know much about the subject and you post up on a thread just to act like a dick then just do us all a favor and save it.

Thanks!

I don't know much about the subject? Hahahaha, you need to open your eyes boy! READ a little before you ask the same question over and over until someone finally tells you that you can make your XJ sound like a porsche!!

 

[seanyb505]

What make a trumpet sound different from a trombone? The shape of the sound chamber. I guarantee the combustion chamber in any supercar does not resemble anything you would see in a Jeep. Airflow also plays a part. Its more than just how much, but how the engine system as a whole is designed for the difference.

Then you have the exhaust piping. Again, the shape and length all play a part. The muffler without question as well. Consider the layout of the Porsche 911 muffler. A long piece that isnt inserted longitudinally. Its almost as wide as the rear bumper. That plays a huge part, but I and other people who havent worked for Porsche probly wont be able to tell you how or why.

This may be a matter of opinion, but what car sounds like a Porsche flat 6? Thats like saying an Evo sounds like a WRX. If you try you will always tell the WRX is coming just by sound.

As much as you might want, youre not going to get your Jeep to sound like a Porsche, or an NSX, even though they are both 6 cyliner engines.

As for empirical data, I dont think you would find it outside of a sound engineering program, and probly not from people who havent attended such classes.

 

[Swamprat]

well when idling my stock xj have an ok sound, but its not loud enough to cancel the mechanical noise when driving. what does suck is that my exhaust is all welded together!! i was going to unbolt it from behind the cat and see what it sounds like, but no!

 

[wolfpackjeeper]

dude, no offense, but the only thing that links that post to the topic is that you said sound and exhaust in the same post.

 

[FlexdXJ]

I had a nice long reply and then it asked me to log in again and then it was lost--bs.
Inline 6s do have a unique sound and I do hear similarities in mine w/ the bmw i-6 w/ aftermarket exhaust(ss, b&b, borla). Port size and shape play a role as does the exhaust system. I didn't get a chance to hear the difference of my head by itself after the p&p(it was installed same time as stroker), but I'm sure it's contributed. Those boxers(porsche and subi) have a unique sound of their own and of course the porsche with its rear engine has short pipes, so that'd be difficult to reproduce. Anyhow, I'm sure there are exhaust gurus out there that can make your vehicle sound a variety of ways(louder, quieter, mellow, raspy, deeper, etc). While on the topic, I'll be shopping for a 95 avus blue m3 come springtime.

Ahhh.... how could i forget about the M3!

 

[Talyn]

Oh great.. another exhaust thread by Purple.

Pretty much every thing about an engine contributes to the way an exhaust sounds. The metal it is made out of, the cam grind, the bore, the stroke, etc. Then you have the different exhaust configurations.. how far the engine is from the tail pipe, even the metal the piper is made of.

 

[gradon]

Yeah, I've been lusting for that car since it came out--like others do for lambos, ferraris, porsches, etc. I can remember sitting in a lhd with the euro-spec motor(independent throttle bodies--286hp) and a 6-speed at the Washington Auto Show in Dec 94. Now that they hover around the $10K range, its about time I picked one up.

 

[t_aldrich]

talyn lol at your sig.

The characteristic "boxer" sound of a porsche or subaru comes from cylinder layout as before stated but also the sound is amplified by the unequal length of the "header" tubes.

ive read a couple of your threads purple. you are truly a shining star here on ... keep it up.

 

[bigalpha]

I'll vouch for the Subaru engines sounding like non-other. I have a Subaru. There's no way to confuse the sound of a 2.2L, horizontally-opposed, 4 cylinder, Boxer engine sounding so unique, you can tell what it is without even looking.

Just like the old VW beetles have their own unique sound. They utilized a Boxer engine as well.

 

[IslanderOffRoad]

I'll vouch for the Subaru engines sounding like non-other. I have a Subaru. There's no way to confuse the sound of a 2.2L, horizontally-opposed, 4 cylinder, Boxer engine sounding so unique, you can tell what it is without even looking.

Just like the old VW beetles have their own unique sound. They utilized a Boxer engine as well.

Sometimes I think there's a helicopter coming when I hear Subies with exhaust.

 

[PurpleCherokee]

So obviously that leans toward cylinder configuration being a big factor in how an engine sounds. So I wonder what the next biggest factor is? I'm guessing it's somewhere in the head??

Another observation: the only four bangers I can stand the sound of, and even LIKE the sound of is the srt-4 and svt focus. FWIW.