V8 Rumble

[Dyno247365]

*sigh* everytime I pop my head in here, you guys make my head spin with knowledge, try to tone it down this time, please? I'm still learning, and I haven't even taken physics yet. That's a good idea I should take physics...err, here's the question. Why does a V8 make a rumble and lower pitched rev then any other engine (even the Viper V10) ?

[bluevp00]

I'm not really sure, but it could be due to displacement. American V8's are very large engines compared to import V8's and are usually the same size or bigger than most V12 engines. The bigger explosion in the cylinder, the deeper the sound. It could also be due to exhaust design, people are used to hearing the V8 rumble, so manufacturers try to create as much rumble as possible.

But that's just my guess, it could be a combination of displacement, exhaust design, head design, and cylinder angle that makes the engine produce a certian sound.

[2.2 Straight six]

it's to do with the pitch (angle) of the cylinders, bore, stroke, the engine design and things like the firing order.

different engines have different charecteristics.

simple enough?

[Dyno247365]

Originally Posted by 2.2 Straight six

it's to do with the pitch (angle) of the cylinders, bore, stroke, the engine design and things like the firing order.

different engines have different charecteristics.

simple enough?

Alright...now I want the info the hard way. I'm aspiring to be an engineer, or atleast I want to study it so I need some serious exposure to this stuff. V8s fascinate me. They're unmistakable when you hear them.

[GreyGoose006]

i think that the noises made by engines is from the valves opening, letting the sound of the explosion echo out, and slamming closed again. the design of the valves wold have an effect on the sound. also, lower idling engines tend to rumble more IMO.

[metallikat]

its going to be more about the bigger explosions of the cylinder, thats a pretty good answer..also, the exhaust has alot to do with it. ive heard plenty of V8's that didnt have a bit of rumble. i had a 77 mustang with a 302 and it didnt rumble a bit. of course, it still had stock manifolds, stock cat and muffler. my 71 mustang, it has no cat and its true dual exhaust with what looks to be some stock glass packs. rumbles pretty good. since youre referring to a "rumble" its obvious its the effects on the exhaust youre hearing, plain and simple. of course how that sound gets to the exhaust has plenty of stipulations that determine that effect.

you want a plain and simple answer? cause and effect my friend!

[curtis73]

If it were simply the displacement or layout, then a 4.3 GM V6 would sound the same as a 5.7 V8. They are the same engine with two cylinders lopped off. Same pistons, head design, everything.

It has to do with the number of times the exhaust receives pulses from the valves and their intervals. The exhaust gets 4 pulses for every revolution in a V8, but only 3 in a V6 and 2 in a 4 cylinder. It also has to do some with the layout. An inline six sounds different from a V6 because inlines typically share one exhaust manifold, while a V6 has to have two.

[metallikat]

Originally Posted by curtis73

If it were simply the displacement or layout, then a 4.3 GM V6 would sound the same as a 5.7 V8. They are the same engine with two cylinders lopped off. Same pistons, head design, everything.

It has to do with the number of times the exhaust receives pulses from the valves and their intervals. The exhaust gets 4 pulses for every revolution in a V8, but only 3 in a V6 and 2 in a 4 cylinder. It also has to do some with the layout. An inline six sounds different from a V6 because inlines typically share one exhaust manifold, while a V6 has to have two.

very good point. i guess it depends on what Dyno247365 meant by rumble. because depending on what kind of exhaust setup you have, you can have a very mean sounding V6. so did he mean deep rumble in general? or the actual loping extremely distinctive sound of a V8?

[Dyno247365]

I'll be specific as requested, not just the idling rumble, but think of the noise it makes getting to and at WOT. I don't know the term for the engine in motion...when you're running the V8, driving it.

[534BC]

It must have something to do with power pulses per (time) or rpm. A v-8 has a definate sound compared to a 12 or a 6, noting it is usually a dual exhaust and may have to do with the uneven firing out of each bank. I have lots of experience with 12's and have heard numerous different sizes of 12's and 8's.

There's something appealing about that sound and a larger v-8 seems to sound better to me. One of my favorite sounds is 5 or 6 blown v-8's on a tractor that run nice.

Now, my favorite smell, hmm.

[psychopathicdude]

Don't forget the very different and distinct sound of a V8 with a flat-plane crank. Sounds more like two high-strung 4 cyclinders in harmony. Or four Harleys in a row. No rumble....more of a scream. Odd, to make a V8 sound more like a Hayabusa...but it'll net you better crank balance, higher redlines, and lower reciprocating weight, due to not needing excessive counterweights. I want one.

[2.2 Straight six]

i don't remember the name of the company, but a over here they've made a 2-litre V8 by efectively "splicing" two 1,000cc hayabusa engines together.

[UncleBob]

Originally Posted by 2.2 Straight six

i don't remember the name of the company, but a over here they've made a 2-litre V8 by efectively "splicing" two 1,000cc hayabusa engines together.

you mean two 1300cc engines. I've seen the video of that. Very cool. over 350hp with stock busa internals.

another cool one is the drysdale bikes, splicing two FZR400 engines for a 750cc V8 that revs to 16K+ RPM's. there's a sound clip of it on their webpage.

If I had a lot of money to throw away, I'd buy one in a heartbeat!

[2.2 Straight six]

i thought they used older 1,000cc engines, no?

i don't have the article to hand, but from memory it said the V8 block was a 2-litre.

[UncleBob]

google is your friend

http://www.radicalextremesportscars....ge/sr8/sr8.php

2.6L engine.