What is the reason for the poor quality of the M6 exhaust sound?

[AbdulBMWi3]

I now possess a 2018 M6 Competition equipped with downpipes and a Burger tune. However, I must admit that the standard sound of the 2019 Mercedes C63 is much superior. What is the reason for the superior sound quality of the C63, despite it being equipped with a twin-turbo V8 engine?

[LostintheSea]

Perception of sound varies from person to person. I personally do not like the sound produced by the exhaust of the MY c63. The false murmurs and vacuum-like noise produced while accelerating just do not appeal to me.

If you have an S63tu M5/M6 that is equipped with a catless exhaust system and either a complete Meisterschaft or a titanium Akrapovic system, it would be very difficult to find a v8 engine from Audi, Mercedes-Benz, or Porsche that produces a more pleasing sound. And I am referring about those automobiles equipped with a complete exhaust system, rather than the standard factory version. Once again, it is important to note that this is a subjective statement based only on my own experience.

[inevitable99]

I presume you are familiar with the reason why conventional V8 engines produce a little uneven sound, which is attributed to their firing sequence.

[AbdulBMWi3]

Indeed, both the BMW and Mercedes possess a dual turbo V8 engine, although they vary significantly in terms of their sound. The firing sequence of a normally aspirated V8 engine does not apply in this case. I am attempting to comprehend the reason for the notable disparity in sound.

[jameswright77]

BMW aims to increase revenue by offering a titanium MPE/AKRA exhaust system, which will enhance the sound quality to perfection.

I replaced my competition exhaust with an Akra exhaust, which was definitely a worthwhile investment.

[sighn34]

BMW does not generate profit from aftermarket exhausts, hence lacking any incentive to pursue such products. Why is it necessary to do several custom modifications in order to get a satisfactory exhaust sound (which may also result in a stronger odour)? Undoubtedly, the E63 AMG in its original state produces a far superior sound compared to the M6, which is likewise in its original state. Mercedes attracts a whole new clientele with this. I would want to examine the sales figures for the two.

My son just purchased an E55 AMG, which has caused me to reconsider my preference for BMW vehicles.

[BentleyOwner]

Mercedes does not approach it in the same manner. Their exhaust manifold closely resembles the manifold found in the 650i. If you locate a 650i equipped with an aftermarket exhaust, you will discover that its sound closely resembles that of a typical V8 engine.

[BMW_Fan2020]

The S63 has a distinct acoustic profile compared to the N63 and other twin turbo V8 engines equipped with a cross plane crankshaft.

The cross plane V8 engine has an irregular firing sequence in which two cylinders on the same bank ignite consecutively.
Left-Right-Left-Left-Right-Left-Right-Right
This is the reason why a cross-plane V8 engine produces a unique burble sound from its exhaust. Each bank of the exhaust manifold receives one exhaust pulse, followed by a pause when the other side fires. It then experiences two exhaust pulses in quick succession, followed by another pause when the other side fires, and so on.

This sequence is suboptimal for exhaust scavenging and also results in unequal flow in the collector (or to the turbine on the turbo).

An effective method to prevent this issue is by using a flat plane crank, which is often used in high-performance engines such as those seen in Ferrari, Ford Voodoo V8, and racing cars. Nevertheless, the current configuration exhibits vibration problems and is unsuitable for a conventional engine.

The optimal option is a 180 degree header, which is most often associated with the original Ford GT40. BMW implements this approach on the S63. Two exhaust ports from each bank are sent to the opposite side of the manifold. The left side collector, namely the turbo exhaust flange, is equipped with two exhaust ports from the left cylinder bank and two exhaust ports from the right cylinder bank. By using this technique, each turbocharger experiences a consistent exhaust pulse, eliminating any irregularities in the pulse pattern.

The reason the S63 has a sound like that of two four-cylinder engines with the standard exhaust is due to its configuration. However, when equipped with a more open exhaust, it produces a sound reminiscent of a racing vehicle.

The photos illustrate the contrast between the S63 manifold and the N63 manifold.

[Lucy_Wilson2002]

Well-written article. I was unaware of this information. The first action I took was to eliminate the simulated emission sound via coding. I was contemplating permanently manipulating the exhaust flap to remain open.

[Sophie_Williams2001]

Alternatively, you might consider purchasing a silencer deletion kit. The sound produced by my S63 F10 M5 is excellent. I do not need any ASD.