What's the difference?

[nicetie]

I have searched for this question and haven't found a good comprehensive answer yet so here it is:
Why does the BMW I6 engine sound so raspy compared to, say a supra or skyline I6 (i.e. what's the difference?)

[MANUALmobile]

Its German hehe!

[JustinE90]

are you complaining about the raspyness?

[FauxFox]

It's the same as why do certain things happen to this engine?

Every engine is different, even if the same size liters.

[DTAP122]

The difference is the bmw is missing 2 turbos...

[FauxFox]

The difference is the bmw is missing 2 turbos...

Then shouldn't the 135i and 335i sound the same as the others?

Not at all

[nicetie]

are you complaining about the raspyness?

No, I enjoy how my car sounds I just want to know what causes the distinctive sound of the engine as opposed to the other I6s. I've always wondered about this. For example; I can tell the difference between ford, chevy and dodge V8s from a mile away and I always thought it was from firing order, but since I6s have all 6 cylinders firing into (usually) a single exhaust manifold, firing order doesn't make sense. I also wondered if it was from compression ratios or combustion chamber size/shape, valve size or cam duration/lift or even if single or dual exhaust pipes made the difference. I can't seem to find a serious answer from someone who knows what they're talking about, all I've seen are just people guessing with no concrete answers.

[325bob]

You've covered most of what I was thinking, all DOHC straight sixes should sound alike, speaking for the exhaust pulses, they are known to be perfectly balanced, maybe BMW has perfected the sound as well as the engine, by exhaust and induction sound engineering?

[Tangent]

My guess is that the majority of it is in the tuning of the exhaust. The "rasp eliminating" exhaust system available for the M3 would seem to support that...

[Kevlar]

It has alot to do with the bore/stroke displacement as well as firing order and exhaust tuning header length and catalytic converters as well as pipe diameter and muffer/resonator use.

[linkE36]

mine just has a thick German accent

[nort0188]

No, I enjoy how my car sounds I just want to know what causes the distinctive sound of the engine as opposed to the other I6s. I've always wondered about this. For example; I can tell the difference between ford, chevy and dodge V8s from a mile away and I always thought it was from firing order, but since I6s have all 6 cylinders firing into (usually) a single exhaust manifold, firing order doesn't make sense. I also wondered if it was from compression ratios or combustion chamber size/shape, valve size or cam duration/lift or even if single or dual exhaust pipes made the difference. I can't seem to find a serious answer from someone who knows what they're talking about, all I've seen are just people guessing with no concrete answers.

D. All of the above.

[pizzaman09]

I was once sitting at a light and heard what I thought was a BMW exhaust note beside me, I looked over to find is was a BMW Motorcycle with a flat 2 cylinder boxer engine. That thing had nearly the exact same exhaust note as my M62 powered e38.

[Critter7r]

No, I enjoy how my car sounds I just want to know what causes the distinctive sound of the engine as opposed to the other I6s. I've always wondered about this. For example; I can tell the difference between ford, chevy and dodge V8s from a mile away and I always thought it was from firing order, but since I6s have all 6 cylinders firing into (usually) a single exhaust manifold, firing order doesn't make sense. I also wondered if it was from compression ratios or combustion chamber size/shape, valve size or cam duration/lift or even if single or dual exhaust pipes made the difference. I can't seem to find a serious answer from someone who knows what they're talking about, all I've seen are just people guessing with no concrete answers.

you answered your own question. ALL of those things matter, however, I'd suspect that they would all sound very similar if you removed the exhause manifolds.

And for the record, my E46 M54 engine has two separate exhaust manfolds.