S4 "active exhaust" ??

[hayasa]

Saw a few uses of the term in overseas press reviews of the B9 S4. What exactly is this and are we getting it in the US?

[hayasa]

So 300 views and no one knows? What I'm referring to is what the press is calling an "active exhaust" and in the past I believe this term was used to make it sound louder via the Drive Select, but this was a fake sound pumped in through the Soundaktor. But since the new S4/S5 is said to not have the fake sound generator any more, I wonder what they are referring to. In other words, does the B9 exhaust have valving to make it louder under exceleration al la the RS5?

For reference, notice the extra stuff (black boxes, metal cylinders, etc.) at the tail end of the exhaust attached to the mufflers:

[dbuxton13]

Any links to source? No idea honestly, and online searches come up empty. In one of the videos I have watched the reviewer showed how the exhaust note changed when switching to sport mode, which denotes some kind of valve switchology.

[hyperunion]

Any links to source? No idea honestly, and online searches come up empty. In one of the videos I have watched the reviewer showed how the exhaust note changed when switching to sport mode, which denotes some kind of valve switchology.

The pictures do show electronic exaust valves.

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[turdzi]

Exactly it's more than a exhaust valve at the back of the muffler controled via audi drive select.Loud in dynamic / quiet in comfort.

[XLR8 Craig]

I'm sure we will be seeing an AWE Switchpath at some point ;)

[hayasa]

Any links to source? No idea honestly, and online searches come up empty. In one of the videos I have watched the reviewer showed how the exhaust note changed when switching to sport mode, which denotes some kind of valve switchology.

Just one of a few reviews below. I think there was an interview with an Audi rep who said something similar.

"A key design element of the S4 is the quad-pipe arrangement, coupled to an active exhaust but no sound actuator, meaning the engine note is always ‘organic’."

Also this one:

"This new V6 feels more awake than the supercharged 3-litre ever did, and it comes with a hearty howl to match its newfound potency – especially with its optional Sports exhaust’s flaps opened to full shriek mode."

[dracolnyte]

i hope it is like whats in the TTS

[hayasa]

Found another cool image of the exhaust, and what really appears to be a valved system. Seems like there is a valve between the split on the drivers' side, and another valve between the two exhaust tips on the passengers' side.

[Ricky Ricer]

This is nothing new. Audi has used exhaust flaps on almost all S models for quite some time.

[sirsycott]

This is nothing new. Audi has used exhaust flaps on almost all S models for quite some time.

minor correction to that blanket statement
b8 and b8.5 S models didn't have it

[hayasa]

minor correction to that blanket statement
b8 and b8.5 S models didn't have it

And I had a B7 S4, also without the flaps. Only the RS models had it if I remember - B7 RS4 and B8 RS5.

[dbuxton13]

So in other words, this *is* something new.

[sirsycott]

at least it's not the fake speakers mounted inside the exhaust like the TDI cars

technically still better than soundaktor playing through your speakers in the car

[JohnEnglish]

at least it's not the fake speakers mounted inside the exhaust like the TDI cars

technically still better than soundaktor playing through your speakers in the car

The Soundaktor doesn't play through the speakers; BMW's system does that. The soundaktor uses the firewall and windshield to amplify and project the sound. The actual device is mounted under the hood against the firewall.

[ModItNow]

I think it's when you press the gas a certain percentage the exhaust valve opens up.


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[JohnEnglish]

So it's like the exhaust on the BMW 335i where it has dual exhaust but the left one only opens above a certain RPM?

[ModItNow]

So it's like the exhaust on the BMW 335i where it has dual exhaust but the left one only opens above a certain RPM?

Thats exactly what I was thinking (the 335i) but maybe opening based on throttle position.


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[hayasa]

I think it appears to be a 3-stage system - both valves closed (light throttle), tail pipe valve opens (moderate throttle or Dynamic Mode engaged), and split valve and tail pipe valves open (full throttle).

[dave329]

Looking at this video at the 22 min mark you see him testing the launch control and can clearly see all the exhaust smoke coming out on one side. The second he releases the brakes and takes off you see both exhaust pipes pushing smoke out.

https://youtu.be/Sgymjj6-ZT0

[hayasa]

Finally, I can confirm that the B9 does indeed have a valved exhaust! Went to the LA Auto Show and they had an S5 on display. Took a photo of the right tailpipe and you can definitely see an open valve. Also got to play around with the virtual display and all the gadgets - and the car is spectacular. Audi seriously raised the bar on this one and it really made the competition look hopelessly outdated and boring.