The mystery of why V8 engines sound so euphonious

Stumbled across a provocative editorial from "Machine Design" magazine a few years ago. Editor, Ron Khol, explores a few theories and "still wonder(s) exactly what it is about automotive V8s that make them sound so good." Surely, the answer resides within this board.

http://www.machinedesign.com/ASP/strArticleID/22215/strSite/MDSite/viewSelectedArticle.asp

 

I've always wondered what a "Crossfire" Ford V8-60 sounded like. This was the hot setup in the day, a special crank and cam that allowed two cylinders to fire at the same time.

 

I think it could be one or a combination of three things.
#1 an 8 cylinder, either V or inline fires once every 90º or 4 times per revolution and a 6, either V or inline fires once every 120º or three times per revolution, so they sound different at the same RPMs.
#2 most V engines will end up with two cylinders firing consecutively on the same bank of cylinders. (If you only had two cylinders firing consecutively on one side and then the other it would sound like a VW!)
#3 One bank of cylinders on a V engine fires pushing the crank down from the vertical alignment of the block while the other bank fires pushing the crank across the vertical alignment of the block. look at it as if it were a drum and you can see how the two "impacts" sound different.

Add #2 to #3 and you get a syncopation of sounds that is not happening in an inline engine.
Try this, drum on top of your desk in 3/4 time and then 4/4 time and see if you can feel a difference...maybe not...
Then drum the same but alternate beats between the top of the desk and the side. To me that 3/4 and 4/4 sound the same, but if you throw in engine RPM the 4/4 is going to be more beats per rpm but they will be doing relatively less work each beat to get the same results so the individual beats are going to be louder, harsher, on the 3/4 time 6 cylinder.

Now, drum on the desk the way a V8 fires:
top-side-top-top-side-top-side-side-(repeat)
That may be why they sound different, and since different engine's firing orders have the same side repeats in different places they sound different. Like an Olds Rocket engine sounds entirely different form a SBC of flatty, and dual exhaust, don't change it but do exaggerate the difference.

 

DrJ, you should be a teacher. I was thinking the same thing, but could not put it in such a concise, easy to understand way.

 

ever here van halens " hot for teacher ". sounds like a nitro burner ready to launch !

 

Syncopation is the answer, although I had never really thought about it in those terms. V8s with 180 degree headers sound like inline engines - sixes, eights, fours - whatever. Flatheads with 180 degree cranks sound like inline engines too, as do any V8s with 180 degree cranks.

 

Dr J's a Professor.

I think he's Superman as well . . . at least if his graduation pic has anything to do with it . . . not sure why, I just have a feeling....

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Ever heard a strongly built V8 running 180 degree headers?
Sounds like an inline 6, a really serious one.

I've noticed as well that single tailpipe V6's at idle sound very much like a V8 at idle.
(Mild cams and all that.)

Inline sixes have that bitchin smooth sound cuz they fire every 120 degrees.
Which leads me to wonder what a set of 120 degree headers would sound like on an inline six.
Pretty good I bet.
Considering you'd have three collectors with two pipes each.

I believe it was Smokey Yunick who ran a V8 with a 180 degree header setup with one collector.
Never heard how it did HP wise, but the sound must have been something else.

If it wasn't such a pain in the ass to build 180 degree headers I've always thought that running one half into a large and very quiet muffler and the other into a short, large ID glasspack would give you a sound like a four banger.
There's something somebody ought to try . . . preferably in a Model A roadster running a short stroke high rpm engine up to about 8500 rpm or so.
Surprise....

 

X pipes sound like that too....

 

maybe it's not so much that it is eight cylinders,

but that it is more than six.

I agree that the number 8 is fundemental in music theory

and the question is in reference to the specific number,

but if you think about other internal combustion engines with other numbers of cylinders, you might notice a one cylinder motor as being a thumping almost heart beat altering jarring noise. a two cylinder motor will sound a little smoother and not so much like a bass drum, more like a pair of congas..
three cylinders are just wrong (who's idea was that anyway?)
then go up beyond eight, ten cylinders sound sweet, sweeter then an eight and a twelve cylinder becomes almost like a humm job..

maybe that's it, the more cylinders, the more erotic the note.

 

Is euphonius really a word? My Flatty sounds better than anything on earth. Thos ethat don't agree are wrong. Thank you.

 

You are correct in that the firing order and engine layout will effect the exhaust note. You also have to add in the effects of the exhaust manifold/headers and the mufflers/tailpipes/catalytic converters. Oops, what H.A.M.B.ers work on don't have those catalytic fire starters.

Exhaust port layout in the heads or blocks matters also. On a flathead, the two middle cylinders on each side both exhaust through the same exhaust port. Flatheads have a very distinct sound that the later design overheads don't have because each of their cylinders usually has its own port in the head. Header design also effects sound. A tri-y layout sounds different than a four-into-one collector.

 

From "The Great Man's Lexicon" - a W.C. Fields dictionary:

euphonious--pleasing to the ear. Fields calls Flower Belle Lee's name in in My Little Chickadee, "a euphonious appellation."

 

That "flathead" sound is shared by some OHV's, notably the early Olds with the siamese ports and also the Y Block.
Big Inline 6's such as the 302 Jimmy and 308 Hudson sound completely different than their smaller cousins. How many here remember the Jimmy powered Willys gassers of old? The sound went right thru you.

You want syncopation? I have many memories of my Navy days during gunnery exercises. You had the slow firing 5", the faster 3", the dual 40mm and the quad 20mm. The combined sound would rumble your bowels, loosen fillings and everything in between. Guys on the bigger ships had 8, 12 and 16" to contend with.

 

Been there, done that.

Taught; stone carving, wood carving, metal forging and fabrication, moldmaking, bronze casting, life sculpture, drawing, plastics fabrication, and three dimensional design.
Also usta manage the R&D and moldmaking department at the auto crash test dummy mfgr.
They moved to Plymouth MI. I stayed here in Paradise...

Now, I clean up cat hairballs, build my toys in the garage, prune the roses in the garden and play on the internet, I pleaded with my wife not to get a damn computer too...
Excessive-compulsive ya know...

 

As long as they didn't rumble your fillings.........

 

bah sound good? nothing beats an hot toyota straight 4 engine with turbo and a dump valve...

 

I always thought that drumline rocked, even when after I cut the mullet and went punk
This thread reminds me of the 'Brown Sound' episode of South Park...

 

I went to school with a Euphonius. Great guy.

 

Who the hell let him in here?

I once heard a badass machine idling through a parking lot from behind a building. Must have been idling at 1600+ RPM, hitting a MEAN lick & just absolutely raising hell through a straight header! I'm thinking, as it's coming closer to the end of the building (& nearly in sight), it must be a built Hemi or something. Then it came around the corner: A SEROIUS Volkswagon Beetle!!! Must've been pushing 250 to 300 HP, normally asperated. It was, as I said, badass!
It had so much compression that it sounded like an 8 cyl. When you think about it the harmonics are similiar to a V8 except for the 180 degree configuration.
~ Paul
aka "Tha Driver"

Since I gave up hope I feel much better.

 

He was joking man.

I know someone with a seriously built corvair, that motor is rowdy. Sounds more vicious than most V-8's i've heard, until it gets some RPM, then it smoothes out quite a bit. I knew a guy in high school that had a bug with a hyper-assed motor in it, almost like a drag motor, it would pound your chest when he rev’ed it, it was insane. There's a couple of Bombs running around here, Chevy 6 and split manifolds and little duals with no mufflers, interesting sound, not nearly as cool as a v-8 though. With a v-8, all you need is some flowing mufflers and even a stock one will sound really good.

 

The next set of headers that I build for a slant six, will be 6 into 3 just for the different sound. I plan on #1 and #2 into one header and so on.
I think it will have a unique sound.

 

I don't remember any car sounding better from the factory than the syncopated, slightly hollow rumble of the dual exhaust on a '66-'67 Olds 442.
Not even a GTO or Roadrunner.

 

...or loosen your bowels!!

 

Dunno', those Offy 4's sound pretty neat at full song.

 

When I build headers for my Plymouth flat 6, I'm going to got down the firing order. so the first three cylinders to fire are on 1 header, the second three on the firing order on the second header.

I also heard rumors of a Mopar flathead pulling tractor motor where the guy cut the crank in the middle, rotated half of it 180 degrees and welded it back together. Along with a custom cam, the firing order was changed to 123456. I bet that sounded different.

 

I always thought that you were supposed to have the pipes that fired before each other, next to each other to create a vacumn to scavenge the exhaust....
~ Paul
aka "Tha Driver"

It's been so long since I've had sex, I can't remember who gets tied up.

 

Performance is one thing ... sound and image is another.

 

A45 degree v twin Harley Davidson sounds better than anything

 

Agree with that. And the first generation IRL V-8s sounded terrible. I think that they had 180 degree cranks.