Yes & No IMO. Like what has been said (ie: Mindgame just above) each engine seems to have its own particular "tone" or "voice". I think it all starts AT the engine ---> IN the combustion chamber ---> against the particular materials (cast iron or aluminum make a difference IMO) ---> out the ports, all different shapes and sizes. Whether a 350 Chevy has headers or manifolds on it, it sounds like a 350 Chevy when it's running. I'm sure a 426 Hemi has its own sound too, whether it's running straight out the headers, or through a full exhaust system. And again, I think that the cam and the compression in the cylinder will have an effect. They'll control the length of the "blast", and the "volume" to a degree, but bouncing off the same materials, through the same ports, it'll sound "kinda" the same out the tail-pipe. Well, that's my opinion anyways!

 

Maybe I have a sensitive ear but I can tell the difference in the Quick Rod sb ford and sb chevy guys at the track. So I dunno.... go listen to them and tell me if you can't tell the difference. Small block mopars.... I can pick them out too.

-Mindgame

 

I did a bit of searching last night on the subject and the only thing I could find was an engineering paper that drew alot of parallels between an engine and the human voice. Sound waves moving from the combustion chamber and the combustion chamber shape playing a part in the frequency, stuff like that. I think that it's a lot of little things. The camshaft profile doesn't mean much.... engines still have a characteristic sound no matter the "lope".
You can even tell a slight difference in tone on a small block with say 23* heads and one with 18* or canted valve heads. Maybe due to combustion chamber, maybe due to the exhaust port. I don't rightfully pretend to know.... just know that they are tonally different. I can also distinguish between Wynton Marsalis and Nicholas Peyton and they both play really similar trumpets.

-Mindgame

 

Im no harmonics expert but ive realised exhaust note is like a drum the diffrent size and rate of change of the cylnder will affect the sound. The bore stroke ratio and cylnder size seems to have alot to do with the note and also the rod stroke ratio may make the engine sound a bit diffrent too. And since the stang has a 4" bore 3" stroke and a short 5" rods this may give it the distinct sound thats coming from behind you .

Eric Myers

 

I think it probably has to do with bore/stroke ratio, and compression ratios. I don't know what either of them are for the 5.0 or 4.6 mustang, but maybe that contributes.

 

I'm with Mindgame. I can't see this being some easy thing, like just heads, or just headers/exaust, I think that every nuance in the chamber (valves) and every bend in the exaust will make some change of sorts. Although yet again I still think putting headers on a car, will just be more of the same, only meaning I can pick out a Ford from a Chevy with no problem, I can't say I've ever heard a Chevy with exaust that sounded like a Ford - even a loud pickup.

I dont have perfect pitch but I've played guitar for 12 years, and no way a Ford sounds like a Chevy with some headers and an H pipe, more too it than that. I also believe that firing order has something to do with it, makes sense to me.

If anyone has watched the making of the V-Rod (Harley), they will show some of the work and tuning that went into making the engine sound the way it does, some of this included thicker metal on some parts of the block (a cover) to quiet the lifters down, they pinpoint sounds with computers and a bank of maybe 20 mics at a time to figure this stuff out.

 

Captn pete,

you mentioned that, "particular materials (cast iron or aluminum make a difference IMO) " why? how in the world would aluminum VS steel make that kind of a diffrence in sound? aside from that, LS1's have steel liners w/ aluminum heads. what about the iron headed 6.0L motors? they sound very similar to LS1's if alumimum really made that big a diffrence, shouldnt aluminum headed SBC's sound similar to LS1 motors? i dont mean to go barking up you're tree, i just want to make a point. i also think that the firing order must play a part in the sound factor. along with several other factors. i.e. bore, Stroke, combustion chamber, mainly because it will change the pattern down the exhaust, much in the same way a diffrent camshaft profile will, resulting in a distinction in tones.

 

How?! Try this.......compare two crank shafts, both from a 350, one cast, and one forged. If you strike any of the counterweights lightly with a hammer, the forged crank will ring for a lot longer than the cast crank will, due to the density of the material. Since cast is basically "gravity formed" vs. forged which is "formed under pressure", all the particles in the metal are that much closer together, therefore the sound will carry on longer (resonate).

...NOW, compare how noise will "sound" or "resonate" through different metals (not just steel to steel, but steel to aluminum) and I'm sure there's gotta be a difference there.

I know you said "what about aluminum headed SBC's??" and I agree, my "theory" might not make sense, but I don't believe there's ONE SINGLE FACTOR that affects the sound, and differences there probably are affected by the actual head design, port design/shape/etc... Like what Dr. Mudge said about how Harley spends so much effort "tuning" their engines to sound like they do, I bet that every little difference makes a difference. I agree with you 100% that bore, stroke, combustion chamber (compression) play a role as well.....I've never disputed that. But IMO, the materials would be a factor to a degree too.

 

"I bet that every little difference makes a difference." agreed ;D

and i see you're point about cast VS steel parts making diffrent resonating sounds. man this has been a great thread..

 

Great thread… seems like most car guys have gotten into similar discussions at one point or another.

Doppler effect… you’ll need to record that and then transpose that recording to a higher frequency so you can understand what the rest of us are talking about.


5.0 ford blocks are cast thinner and out of higher nickel iron then most SBC’s, the Iron is more similar to what was used for Pontiac V8’s. The Iron and construction used for other SBF’s is closer to what is used on SBC’s, but still higher nickel content (351’s never got lightened by ford because they were used in trucks).

I’m not sure that this is really much of the issue, since the level of the ‘chamber’ (block) resonating should be so low that you really won’t hear it. Somewhat like a properly built speaker enclosure, as long as that enclosure is dense enough you really won’t hear much coloration from the enclosure.

no, you’ve got that backwards. When you add a second port to a box it’s Fb (resonant frequency of the ‘box’) goes up. For that matter, essentially the port/enclosure tuning frequency is a relationship between box volume, port volume and length. The more port diameter you have the longer the port length needs to be to tune for the same frequency, the larger the enclosure volume, the shorter the port has to be to tuned for the same frequency.

Most SBF’s have significantly smaller exhaust ports then similar SBC’s. SBF ports in general are shorter.

There’s a few things along these lines that really bother me (in other words, I don’t have a good explanation):
- How similar SBF’s and the mod motors used in mustangs sound
- Ford used 2 different firing orders in SBF’s and although they do sound different, most people can’t hear the difference (read: very similar sounding), for that matter, it’s fairly difficult to tell the difference between their factory headers and cast manifolds (put an h-pipe and louder mufflers on an ‘80’s bronco with a 302, different firing order and manifolds instead of headers like the HO302 and they sound the same)
- This one really bugs me: a SBC 305 sounds completely different then a 350. 305’s sound lower and much smoother then nearly identical 350’s, to the extent that you can run headers, cats and a straight pipe on a 305 and it sounds nice (for that matter, you can run just about anything on a 305 and it sounds good), a 350 with the same exact setup (literally swapped, so same body style, same compresson, same heads, same cam…) sounds awful, like a redneck truck with an exhaust leak. TPI 350’s sound almost exactly like LT1 350’s, and nothing like TPI 305’s even though the 305/350 have the same intake, cam, heads, manifolds, exhaust, and all of those are different on the LT1. Stranger still, LS1’s sound about halfway in between 305’s and 350’s, mellower then 350’s but not as smooth as a 305. Of the ones that I’ve heard, 383’s, 396’s, 400’s… all sound very similar to a 350. Most mild big blocks sound like 305’s. I would love to get a 350 or larger SBC/LT1 to sound like a 305

 

The old 289/302 Fords had a different firing order than the 5.0's. The 5.0s had the same firing order as the 351W's. The old 302 firing order is the same as a SBC, the cylinders are just numbered diferently. I remember reading that the LS1 has the same order as the Cadilac 500's.

 

symmetrical port heads

 

One thing I dont remember being offered is fuel type and fuel delivery. Obviously street cars aren't going to run 'nitro', but I do notice that many carburated cars, and even by carb type make the car sound different. Such as a single 4 barrel, versus 4 -2 barrel Webers, or etc, intake manifold would be different too obviously (or use a spacer-adapter).

 

I've heard from others that it is a combination of things(firing order, block material, cylinder head design, camshaft variances, compression ratio, exhaust set-up, etc...) that gives each and every motor it's "own" sound. Some may sound very similar, but you can still "hear" the difference. As to exactly why, I have no idea(I'm clearly not a V8 sound engineer).

Doesn't an aluminum block absorb more of the sound being put out than a cast-iron block? Not sure if this is why stock LS1's are sooooooo damn quiet.

And again, I've heard LS1's were designed with the non-traditional firing pattern by GM with the intent to give them a quieter and smoother idle along with less noisy road quality. Anyone else heard this? It does seem to make some sense. Although I'm not sure how "mild" a stock LS1's cam is to that of a stock LT1's, which would also make a difference.

How specifically would the different compression ratios affect sound quality of a specific motor? Don't the LT1's and LS1's have different stock compressions?

That aside, stock cammed/exhausted LS1's are the wimpiest sounding V8 muscle cars I've ever heard at idle. Even with an aftermarket cat-back, they are still very mellow and quiet when idling(it takes a decent sized cam to really hear them). I'm not fond of their overall sound quality either. On the other hand, a stock LT1 with just a simple cat-back change sounds a world of a difference better to me. LT1's by far and away have my favorite sounding exhaust tone of any SBC or muscle car on the road(I never get tired of hearing their deep throated rumble).

Mike

2002 M6 Z28
!CAGS, Direct-Flo lid, MAFT, & GMMG Chambered Exhaust
325.1 RWHP & 346.1 RWTQ @ 2,213 miles SAE corrected

 

I remember hearing it was to quiet them down (idle), but it is also a superior firing order in terms of pulsation is it not?