[hufington]

I have been pondering about doing this since I ordered the car in December '21.

6 months forward, I have deleted the factory resonator and the sports exhaust in the back. Even with the flaps open thru bimmerlink, there was not much of a sound that matched the 8-cylinder engine under the hood. I also deleted the flaps and actuators.

I used a custom-made 3-inch in-and-out x-pipe to replace the resonator. The resonator that came with the car is actually a resonated x-pipe in the '22 model m50i (that has the standard msport exhaust) as there is a small opening to create a mix of the exhaust gas coming from both banks. However, the inside diameter of the resonator was smaller than the overall pipe diameter of 3 inches and it had to go.

In the back, I used custom-made stainless-steel muffler boxes with lots of high-quality sound dampening material (3-inch straight-thru, approx. 12"x8"x5"). If you'd like to buy something off the shelf, I'd say get two 3-inch vibrant ultra quiet resonators.

And for the quad tips, I used stainless steel 4-inch slanted tips to match the curvature of the bumper. Any 4" tip with a maximum width of 8" and depth of 10" would fit. The opening after removing the OEM tailpipe is big enough to accommodate double 4" tips on both sides but there is only limited space up and down. As I said, mines were 10 inches long and 8 inches wide at the tips, which fit perfectly. Remember, you need to get slanted tips. (Visit the following eBay store: hybers11 | eBay Stores )

The total cost using all stainless steel material (including the tips) was $350 + whatever you'd pay for installation.

The car in standard trim (with msport exhaust) sounded like this:

And with the custom setup it sounds like this:

I am very happy with the result. The car pulls much harder at mid to high rpm and has a matching sound, which is not very loud but noticeable from the outside and audible inside the car.

If you want to be able to use the factory valves and have no sound at all at times, you may not want this setup.

 

[speedyman]

Much improved exhaust note.
I'll bet it sounds even better at high rpm under acceleration/load.
Good job. These V8 powered vehicles for the US market should not be muffled down to the degree that the Euroweenies prescribe. The meat eaters who buy this high powered stuff want to hear some healthy 8 cylinder muscle at work.

 

[hufington]

Much improved exhaust note.
I'll bet it sounds even better at high rpm under acceleration/load.
Good job. These V8 powered vehicles for the US market should not be muffled down to the degree that the Euroweenies prescribe. The meat eaters who buy this high powered stuff want to hear some healthy 8 cylinder muscle at work.

Correct. It sounds fantastic at load after 3k rpm.

 

[speedyman]

Correct. It sounds fantastic at load after 3k rpm.

It should have sounded that way from the factory with a call switch for quite/louder capability. Unfortunately we got a Euro puss version of the M Sport exhaust.
Looks like you solved those problems along with much more aggressive quad tip exhaust that a vehicle shown to produce over 550 HP would be expected to have.

 

[hufington]

It should have sounded that way from the factory with a call switch for quite/louder capability. Unfortunately we got a Euro puss version of the M Sport exhaust.
Looks like you solved those problems along with much more aggressive quad tip exhaust that a vehicle shown to produce over 550 HP would be expected to have.

Agreed.
I could have installed a double pipe solution with an exhaust flap to lower the sound level with the touch of a button.
However; I think that this SUV will be probably one of the few 8-cylinder vehicles in the BMW line-up in coming years and as buyers, we all will be forced to buy electric "appliances" with no real engine sound at all. Considering that, I wanted to enjoy it as much as I could.