Legion5

So I was playing around with the baby stang and took off the ford axle back, i actually really loved the sound of the car while I had my co-worker play around with it in neutral gear but once we got into gear and took it for a spin the engine management let it go above 4,000 rpm and the car sounded HORRIBLE, it went from a nice deep chest thumping tone to well, this high pitched whail that was one of the worst exhaust notes i've ever heard.

I actually liked the sound without the mufflers so much it prompted me to make this post to let everyone know, and I'm really trying to consider and spend some time to figure out how to stop this horrible wailing both theoretically and practically.

What in the world is going on in the unmuffeled exhaust pipe to make it so terrible? How to fix it?

http://www.youtube.com/watch?v=HJwfFCuvXMw

in this video with a completely differently set up car you can hear the sound i'm talking about when the car takes off and goes off camera, that wailing sound is exactly like that (1:04).

basketballord

There is a simple answer: It's a V6. Having no muffler on a V6 sounds like poo at high RPM. I stand by that statement 100%, but I know some people on here will decide to debate that, as we have done before.

On the other hand, having no muffler on a V8 sounds loud and mean as hell. A v6 and a v8 are just different animals. Different displacements, different firing orders, etc. You won't get a v6 to sound like an 8, no matter how hard you try. And a muffler-less v6 sounds like crap at high RPMS

Norm Peterson

It is mostly due to the fact that 60° V6 firing order always alternates bank to bank, while most all 90° V8 firing orders have cylinders on the same bank firing in sequence every so often. Basically, there isn't much that you can do to make a V6 sound like a traditional V8 under heavy load over the full rev range.

I guess you have to have an appreciation for high-revving sixes (maybe think Jaguar E-type, Porsche 911, most of the recent 3-series BMWs, 350Z) or 4-cylinder sport bikes in order to like that sort of sound.

I'm also guessing that since the OP mentioned "deep chest thumping tone" that the sound of lots of low end torque means more to him than the sound of pure revs.

Can't argue with what people prefer, but I can give pictures that show the difference. What you hear from the traditional V8 sounds like the top chart (those widely spaced high peaks is your low frequency rumble). Although the bottom chart was plotted for a V8 with different sort of exhaust system, a V6 will sound similar to that (more of a high-pitched 'snarl' without any 'rumble' to it).

Smooth tone or rough rumble - your choice .





Norm

ODDYSEY

As soon as he took off down the road it sounded worse than poo. It was horrible! The car only sounded good at idle, even a little bit up the RPM chain started to sound bad.

Just my opinion though.

28HopUp

That's Jenna's car, and you have to remember that she had also removed the catalytic converters in that video clip. These 4.0L's sound even worse without cats. She has an awesome turbo 4.0L, which she built/installed herself.

antipeterleague

wait, what is the question here?

Norm Peterson

The hidden one is probably "how can I make my sixxer sound like an eight".

At the very best, the answer is "not easily".

Maybe if the exhaust primaries from the middle cylinders of each bank were crossed over to the opposite side collectors you'd be closer. But that's pretty deep into experimental territory and there's some risk of ending up sounding a little like an old VW or Subaru flat-four under some conditions.


Norm

Sancho805

FRPP or JBA muffs, H-pipe duals, LT headers....... maybe then it will close the V6-V8 sound gap to its closest point. still nothing you can do to make it sound "JUST LIKE" a V8.... less cylinders, different firing order.

i don't understand the need to make it sound just like a V8. the 4.0 is its own machine and with the proper setup, still sounds better than most cars on the road. i run across a ton more hi revving 4bangers that sound like crap which makes my stang sound like one mean hombre. not as many V8's on the road that are setup to intimidate. tricked out full size trucks seem to dominate the sound category around these parts.

Legion5

The problem has nothing to do with gutting the cats. Gutted cats, high flow cats, off road pipes, or stock cats every exhaust clip I hear sounds exactly the same with regard to the v6 without mufflers above 4000 rpm.

Below is the clearest example of the problem.

http://www.youtube.com/watch?v=UTjAyuLkkZM

this actually has nothing to do with trying to sound like a v8 because i'm insecure I'm just trying to understand how to eliminate the horrible high rpm wail.

To prove that I can point out I already have a fully modded v8.

I'm talking about a specific and very direct high rpm whailing problem which I've read about took a lot of effort from 6 cyl engine designers at porsche to fix but after looking up no muffler videos of porsches online it seems the mustang is the worst example of the problem in car history which makes this thing big.

Norm Peterson

I'll have to listen later (internet filters at work, y'know).

But once you have the right (wrong?) forcing function, the details of exhaust system resonances are likely to make it worse in certain rpm ranges.


Norm