NA vs Turbo sound...

[Mastodon2]

Welshbeef said:

An abrovamich exhaust resolves that issue just like is does for he mute E92 M3 OEM exhaust

A what?

[Alpinestars]

toohuge said:

One of the closet comparisons could be the Porsche flat - 6, in the 997 GT3 & turbo. Both Mezger, same number of cylinders etc. one has 2 turbos, the other is NA - how different do they sound?

Massive difference between a 997 gt2 (bland sound) and a 997 gt3 (magic sound).

[Welshbeef]

Alpinestars said:

toohuge said:

One of the closet comparisons could be the Porsche flat - 6, in the 997 GT3 & turbo. Both Mezger, same number of cylinders etc. one has 2 turbos, the other is NA - how different do they sound?

Massive difference between a 997 gt2 (bland sound) and a 997 gt3 (magic sound).

That's revs too though.

Limit the GT3 to 6k max like the Turbo and it will be less nice.

[Alpinestars]

Welshbeef said:

That's revs too though.

Limit the GT3 to 6k max like the Turbo and it will be less nice.

Agreed it would be "less nice", but there's still a much better sound to the gt3. The gt2 is pretty boring.

[sebhaque]

When buying my C63 I drove both the new 4.0 twin turbo V8 and the original 6.2 V8 version. I couldn't justify the price difference to buy the new one. The engine sounded strangled, and artificial when it made the odd burp. The larger NA V8 just sounded like it was angry all the time.

I love a turbo where cars are designed to have a massively turbocharged engine. The typical Jap cars (I had a blobeye STi and an Evo 8) were absolutely brilliant with a snail - as was my VX220. That being said, I don't think I'd like a turbocharged M3/C63, nor would I like a forced induction 370Z.

Cars are built around their sound and while the Nissan GT-R can sound fantastic, the majority of them are modified to do so. Most turbocharged cars nowadays sound a bit less impressive than their NA older brothers. One only has to look at F1 for an example (I'm not willing to debate the benefits of fuel economy etc, which petrolhead buys a car for that?!)

[BigLion]

sebhaque said:

When buying my C63 I drove both the new 4.0 twin turbo V8 and the original 6.2 V8 version. I couldn't justify the price difference to buy the new one. The engine sounded strangled, and artificial when it made the odd burp. The larger NA V8 just sounded like it was angry all the time.

I love a turbo where cars are designed to have a massively turbocharged engine. The typical Jap cars (I had a blobeye STi and an Evo 8) were absolutely brilliant with a snail - as was my VX220. That being said, I don't think I'd like a turbocharged M3/C63, nor would I like a forced induction 370Z.

Cars are built around their sound and while the Nissan GT-R can sound fantastic, the majority of them are modified to do so. Most turbocharged cars nowadays sound a bit less impressive than their NA older brothers. One only has to look at F1 for an example (I'm not willing to debate the benefits of fuel economy etc, which petrolhead buys a car for that?!)

Why is the engine and exhaust noise so different on turbos - intuitively you would think there is more air and fuel in the combustion chamber so everything should sound like a NA but on steroids?

[kambites]

BigLion said:

Why is the engine and exhaust noise so different on turbos - intuitively you would think there is more air and fuel in the combustion chamber so everything should sound like a NA but on steroids?

Because there's a damned great turbine sitting in the way of the exhaust gas.

With a naturally aspirated engine you get very clear, staccato, exhaust pulses at the tail-pipe each time a cylinder fires; with a turbocharged engine, the build up of back-pressure behind the turbine means the individual pulses from each cylinder are slurred together into a more continuous drone.

[cobra kid]

Welshbeef said:

YouTube AC Cobra 427 sound doesn't get much better from a NA big block v8

Then you tube A launching from a Rally Stage of a say Lancia S4 evolution or a Audi ur Quattro S4 etc.

They all sound good to me but I'd take the Cobra every single time - even assuming the values are all equal.

mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm

[havingabarth]

Mastodon2 said:

Welshbeef said:

An abrovamich exhaust resolves that issue just like is does for he mute E92 M3 OEM exhaust

A what?

[Alpinestars]

kambites said:

Because there's a damned great turbine sitting in the way of the exhaust gas.

With a naturally aspirated engine you get very clear, staccato, exhaust pulses at the tail-pipe each time a cylinder fires; with a turbocharged engine, the build up of back-pressure behind the turbine means the individual pulses from each cylinder are slurred together into a more continuous drone.

That's a good explanation.

[Welshbeef]

havingabarth said:

Mastodon2 said:

Welshbeef said:

An abrovamich exhaust resolves that issue just like is does for he mute E92 M3 OEM exhaust

A what?

Haha superb

[Wills2]

Exhaust noise is overrated and often contrived (See F-type/C63 as prime flatulent examples) induction is where it's at, M used to be masters of it the S54 and the S65/S85 sounding incredible at high RPM, the new turbo Ms not so much!

[Welshbeef]

Wills2 said:

Exhaust noise is overrated and often contrived (See F-type/C63 as prime flatulent examples) induction is where it's at, M used to be masters of it the S54 and the S65/S85 sounding incredible at high RPM, the new turbo Ms not so much!

Disagree with that sorry.

A lovely burbling V8 then blipping the throttle is great.
Induction is good but exhaust superior - excl dustbin exhaust added to 1ltr Nova's.

[jamieduff1981]

Alpinestars said:

kambites said:

Because there's a damned great turbine sitting in the way of the exhaust gas.

With a naturally aspirated engine you get very clear, staccato, exhaust pulses at the tail-pipe each time a cylinder fires; with a turbocharged engine, the build up of back-pressure behind the turbine means the individual pulses from each cylinder are slurred together into a more continuous drone.

That's a good explanation.

Doubly so because the same is true of the intake as well. You no longer hear the individual induction strokes attenuated with resonance being drawn through the throttle body(or multiple). What you hear instead is more-or-less continuous sucking from a centrifugal compressor. The intake sound is muted by an intercooler, compressor and all the additional pipework between.

[kambites]

jamieduff1981 said:

Alpinestars said:

kambites said:

Because there's a damned great turbine sitting in the way of the exhaust gas.
With a naturally aspirated engine you get very clear, staccato, exhaust pulses at the tail-pipe each time a cylinder fires; with a turbocharged engine, the build up of back-pressure behind the turbine means the individual pulses from each cylinder are slurred together into a more continuous drone.

That's a good explanation.

Doubly so because the same is true of the intake as well. You no longer hear the individual induction strokes attenuated with resonance being drawn through the throttle body(or multiple). What you hear instead is more-or-less continuous sucking from a centrifugal compressor. The intake sound is muted by an intercooler, compressor and all the additional pipework between.

The difference with the intake is that modern cars tend to have so much sound-deadening you can't really hear the natural intake noise anyway; instead they route the sound straight from some point in the intake system directly into the cabin through a hole in the bulkhead. I don't actually know where they take that feed from (I've never owned such a car) but I see no reason it shouldn't be from the intake manifold, which would largely negate the damping effect of the compressor?

I think they're increasingly going down the route of playing a noise through the speakers instead of physically tunnelling it from the engine bay/exhaust anyway, which makes the whole thing rather a moot point.

[C7 JFW]

Welshbeef said:

YouTube AC Cobra 427 sound doesn't get much better from a NA big block v8

Then you tube A launching from a Rally Stage of a say Lancia S4 evolution or a Audi ur Quattro S4 etc.

They all sound good to me but I'd take the Cobra every single time - even assuming the values are all equal.

You can keep your 'big block' V8's.

German M3 V8, like ripping paper (I think the yanks call it) - now that's what I call a V8.

My S2000, brilliant N/A, the crispness.

Nissan Skyline GT-R, sounds absolutely incredible turbo charged.

[jamieduff1981]

kambites said:

jamieduff1981 said:

Alpinestars said:

kambites said:

Because there's a damned great turbine sitting in the way of the exhaust gas.
With a naturally aspirated engine you get very clear, staccato, exhaust pulses at the tail-pipe each time a cylinder fires; with a turbocharged engine, the build up of back-pressure behind the turbine means the individual pulses from each cylinder are slurred together into a more continuous drone.

That's a good explanation.

Doubly so because the same is true of the intake as well. You no longer hear the individual induction strokes attenuated with resonance being drawn through the throttle body(or multiple). What you hear instead is more-or-less continuous sucking from a centrifugal compressor. The intake sound is muted by an intercooler, compressor and all the additional pipework between.

The difference with the intake is that modern cars tend to have so much sound-deadening you can't really hear the natural intake noise anyway; instead they route the sound straight from some point in the intake system directly into the cabin through a hole in the bulkhead. I don't actually know where they take that feed from (I've never owned such a car) but I see no reason it shouldn't be from the intake manifold, which would largely negate the damping effect of the compressor?

I think they're increasingly going down the route of playing a noise through the speakers instead of physically tunnelling it from the engine bay/exhaust anyway, which makes the whole thing rather a moot point.

I haven't looked in detail, but I can't imagine leaking boost pressure into the cabin would be a good idea. I'd always assumed that such intake sound plumbing would have to be upstream of any compressor.

[kambites]

jamieduff1981 said:

I haven't looked in detail, but I can't imagine leaking boost pressure into the cabin would be a good idea. I'd always assumed that such intake sound plumbing would have to be upstream of any compressor.

There's no air-path, I think it's generally a tube with a sealed diaphragm on the engine end.

[Krikkit]

jamieduff1981 said:

kambites said:

jamieduff1981 said:

Alpinestars said:

kambites said:

Because there's a damned great turbine sitting in the way of the exhaust gas.
With a naturally aspirated engine you get very clear, staccato, exhaust pulses at the tail-pipe each time a cylinder fires; with a turbocharged engine, the build up of back-pressure behind the turbine means the individual pulses from each cylinder are slurred together into a more continuous drone.

That's a good explanation.

Doubly so because the same is true of the intake as well. You no longer hear the individual induction strokes attenuated with resonance being drawn through the throttle body(or multiple). What you hear instead is more-or-less continuous sucking from a centrifugal compressor. The intake sound is muted by an intercooler, compressor and all the additional pipework between.

The difference with the intake is that modern cars tend to have so much sound-deadening you can't really hear the natural intake noise anyway; instead they route the sound straight from some point in the intake system directly into the cabin through a hole in the bulkhead. I don't actually know where they take that feed from (I've never owned such a car) but I see no reason it shouldn't be from the intake manifold, which would largely negate the damping effect of the compressor?

I think they're increasingly going down the route of playing a noise through the speakers instead of physically tunnelling it from the engine bay/exhaust anyway, which makes the whole thing rather a moot point.

I haven't looked in detail, but I can't imagine leaking boost pressure into the cabin would be a good idea. I'd always assumed that such intake sound plumbing would have to be upstream of any compressor.

In N/A applications of a "sound generator" it's always noise pre-throttle plate on the intake. Wouldn't work quite so well on turbo cars if you were leaking boost pressure into the cabin! The only way you could do it on a turbo would be before the compressor-> still the same problem.

[jamieduff1981]

kambites said:

jamieduff1981 said:

I haven't looked in detail, but I can't imagine leaking boost pressure into the cabin would be a good idea. I'd always assumed that such intake sound plumbing would have to be upstream of any compressor.

There's no air-path, I think it's generally a tube with a sealed diaphragm on the engine end.

Ah I see. Even still, I would have thought a diaphragm would just inflate under boost? I dunno. I haven't looked at what's involved as I said