Just curious too, has anybody heard up close a true dual exhaust on an LT1. I know there are sound clips out there, but I've found that none of clips out there do justice to the true sound of an exhaust

I had another thought as well, again, this stems from an audio perspective. If you take a bix, and throw two long ports in it, that have a 2.25" diameter in it, if I am not mistaken this will result in a lower frequency "boost" compared to a single (same length) port with a larger diameter.

From a flow perspective, wouldn't the exhaust velocity leaving the Ford exhaust be significantly slower, since it is consuming less air/fuel, however has a much better flowing exhaust?

If that were true, then comparitively speaking, the LT1 would have much higher exhaust velocities, which would contribute to (at least in car audio "port noise", or whistle) near the tail pipe if the velocities approached the speed of sound. While that may seem fast, it's really not, considering when you can "hear" the wind blow, it means that the air is exceeding the speed of sound (usually because it is flowing around something such as a window trim piece, or a car antenna)

The more and more I look at it I think Oldstroker hit the nail on the head, it's the exhaust and less the engine. I had always previously thought it was almost exclusively the cam, since that's pretty easy to tell the lopiness between 2 cams, but that's obviously only a small part of the story.

I know that the number of cylinders is probably the biggest contributor of the sound, however the Stang has 8 slugs too, so that's a wash.

Thanks for the input guys, didn't expect all the excellent thoughts

 

i would like to see somebody put a mustang exhaust on a chevy.

 

Take the exhaust out of the equation.

If you have an engine builder somewhere close who builds a variety of different engines, go down and check out their dyno room. No exhaust systems accept for headers and maybe mufflers.
You'll still notice a very distinct difference in engine sound..... ford, chevy, mopar, olds, buick, pontiac..... all a bit different tone.

Same thing at the strip with cars that aren't running full exhaust systems (just headers, mufflers and dumps). Or just check out the dragsters, although most will likely be chevy powered. One gentleman here locally runs a ~45x ci mopar, very different sound from my big block Mullis.

-Mindgame

 

Actually sounds like a cool idea Mindgame, heh, around here, all I hear is 4-bangers with 2" inlet/6" outlet mufflers

 

I have. Hooker LTs, high-flow cats, and Bullets in a TRUE dual, no x-, h-, or y-pipes. Straight from each header out the back. Man, it had a sound that would make mustang owners cry. DEEP, clearly defined pulses and no raspiness. I couldn't believe it.

[EDIT]- forgot to mention, this was from an LT1 transplanted into a silverado with the stock cam.

 

Ever hear a cammed LT1 stroker flowing through Hooker LTs and a 4" Mufflex exhaust system with a Flowmaster for sound reduction? Now that's a sweet combo that I'll put up against a 'stang anyday......

 

i always thought the difference between LT1/LS1 and 5.0 was the exhaust systems. all mustangs have true dual exhaust and 5.0s even have mini headers from the factory. but even that isnt what i think is the main reason. what i believe is it all has to do with stang owners being hardcore info flowmaster. i bet 90% of aftermarket systems on stangs these days is a flowmaster which explains why the all sound the same. i have also heard several LT1 and LS1 cars with flowmaster catbacks and i swear they both sound very similar to the stangs.... that hollow, tinny exhaust note. i bet a 5.0 and LT1 would sound nearly exactly the same if the exhaust systems were the alike from the headers all the way to the tips. about the 4.6 modulars. they sound amazing and totally different than a 5.0 or LT1/LS1 IMO.

 

Are we talking engine sound or exhaust sound, because many cars do not have much of a sound, besides the exhaust, the sound from the motor itself depends on piston shape, as someone mentioend hemi makes one sound, most likely due to it's unique piston design, also the cam has a lot to do with it, even between roller cam solid cam, also I'm sure the firing order has a little bit to do with it, but in my opinion it has a lot to do with the exhaust, and on a side note, I have a 383 with an SLP 3" cat back driver side exhaust, and my friend has a mustang stock size v8, I thinkit's 297 they use now, or whatever pelase he uses an aftermarket exhaust, cam, etc, and our cars sound very similar.

 

Nah, they can sound very much alike. Even a DOHC 4.6L CAN sound very Ford like.

 

In my experience, the exhaust configuration is the determining factor of the sound characteristics. OldSStroker is correct. One thing that I haven't seen mentioned is the header/manifold configuration. I'll get to that in a minute.

The Mustang sounds very clean and smooth because it is a full dual setup with an H-pipe and a significant length of tailpipe behind the silencers. The mufflers are specifically tuned to give that sound. The H-pipe is there for acoustic reasons and is a necessary part of the whole acoustic package.

Headers/manifolds are important because the closer to equal length the distance is between each exhaust port and a y, h, or x junction, the fewer odd engine orders (acoustic) need to be tuned out. In other words, the closer to equal length primaries, y-pipe legs or tubes before junctions, the cleaner the sound. It's much easier to tune a muffler for a primary firing frequency than for a 3/8, 1/2, 5/8 or 1.5 multiple of firing frequency. Equal lengths allow the odd frequencies to cancel each other out.

Now back to the f-body. A manifold, unequal length y-pipe legs, and a muffler towards the rear of the vehicle means lots of odd frequencies popping up and a more difficult time dealing with them. Add LT's and the situation improves, but the tubes are still not equal length. True duals with an X-pipe you say? Bullet style mufflers (no tuning) with very little pipe behind makes for a cleaner sound, but loud. Definitely not the frenetic wail coming from the Mustang.

I haven't been able to test this, but I suspect that if you could put different manufacturers' engines (of similar displacement, important point) on an engine dyno with identical headers/manifold, y or x/h pipe, silencers and pipe configurations, that they would sound nearly identical. The only way I can think to do this would be with the engine on a stand and the exhaust in a hemi-anechoic chamber. Needless to say, no one has done this, and the prospects aren't very good for such a test.

Just for information, if you were to look at what are called order tracking curves (basically sound curves that track noise level as related to engine firing frequency) for both cars, you would see that the Mustang is dominated by fundamental firing frequency sound, while the Camaro has fundamental and lower frequency odd multiples dominating. In many places, the lower odd multiples are significantly above the fundamental in sound pressure level. This is why you hear a much deeper rumble from the Camaro than from the Mustang.

Great thread.

 

I disagree with the firing order theory. IMO, the reason an LS1 doesn't sound like a "traditional" SBC is because it's A) aluminum, and B) doesn't have a "lumpy" cam. To me, the LS1 (with stock exhaust) "sounds" like a throaty 2.8/3.1L GM V6. I've heard one with a Borla exhaust, and while it was louder, and sounded "better", it still didn't sound like a true SBC.

Now most of my experience so far has been with Gen-I SBC's (many 350's, and the 383 in my '81). Regardless of what type of vehicle they've been in (Camaros, S-10 pickups, other old cars) or whether the engine used cast iron manifolds or headers, if they were cammed engines, they would have a particular "throaty, lumpy" tone, that is very much similar to SB Fords (more "raw" and "mean" IMO). Even when my friend put headers and true duals with Flowmasters on his '75 Chevelle, it sounded nothing like my Z28 with the 383 --- IMO because his 350 was bone-stock, with low compression and not much lift on the cam --- whereas my 383 had better compression, and a much lumpier cam. BUT, even with that said, it sounded more like what a 350 should sound like, than what a stock LT1 or LS1 sounds like.

What I can say though, is that the same guy with the Chevelle now has a '96 T/A that he put a Borla cat-back on. IMO, it sounds darn close to what an old SBC "should" sound like (very comparable even to a 5.0L).

I don't know what gives 5.0L Mustangs their sound (when they're stock), but IMO it's gotta be something to do with the cam (maybe LSA if not lift?? ) and maybe a little to do with true duals?! Whatever it is though, I know that they don't sound any better than an old SBC. My dad's '73 sounds very close to my old 383 (maybe even louder?!) and the sound makes me wet myself!!!!

 

The exhaust design has very little to do with the difference, at least in my experience. I have heard dozens of cars without exhaust and as Mindgame suggested, they still sound very different.

I would have thought that the 302 sounds different than say a 350 chev because of it's big bore/short stroke, but then a 302 Chev doesn't sound like a Ford....

 

I've never heard a car without an exhaust on it, most people haven't. Headers or manifolds are on any engine and that's where the tuning starts. That is why I'm saying that header design is so important to the overall acoustics of the system. Like I said, until someone does a test where each configuration is identical, we'll never know.

 

Cars without exhaust systems..... aka dragsters.

Like I said in my other response, go out to your local drag strip and listen to the dragsters. Lots of people are into Quick Rod class dragster racing, myself included. You'll see lots of guys running chevy, ford and mopar. Chevies are definitely more popular but lots of guys are ford or mopar loyalist just like anything else. I use to run a 351C in one of my old cars, very different sound from my big block chevy, very different sound from my buddy's mopar powered dragster. Just like people have different tonalities to their voice, engines have different tones also. Mind you, these engines only have headers (although some are now running the Borla header muffs) so it's a relevent way to compare.

-Mindgame

 

A 351C is going to sound different than a BBC or a Mopar Dragster. The combustion events are significantly different between the three (that's what makes the noise). I'm talking about similar displacement and power, say, a 351C and a 350 SBC, similarly tuned and outfitted with as close as possible to identical headers, drag pipes, manifolds, whatever. The sound character would be similar enough that I think most would be hard pressed to tell them apart.