[CalgaryAndUK]

Love my new X3 M40 (picked up from Vines of Gatwick in UK 2 weeks ago). However, have noticed that if I am just driving along normally, then I slam the accelerator down to get the car to shoot off at max acceleration, the car makes a deep boom sound as it changes down gear initially, and then once more as it shifts up to the next gear. I have owned a few performance cars and none made this sound. Can anyone confirm if their M40 does the same thing? It comes from the rear of the car, probably the exhaust. Not sure if it is a fault or supposed to be like that....?

[ParadigmDawg]

Originally Posted by CalgaryAndUK

Love my new X3 M40 (picked up from Vines of Gatwick in UK 2 weeks ago). However, have noticed that if I am just driving along normally, then I slam the accelerator down to get the car to shoot off at max acceleration, the car makes a deep boom sound as it changes down gear initially, and then once more as it shifts up to the next gear. I have owned a few performance cars and none made this sound. Can anyone confirm if their M40 does the same thing? It comes from the rear of the car, probably the exhaust. Not sure if it is a fault or supposed to be like that....?

Totally normal. My AMG does it too but it's much, much louder then my M40.

[Dzo]

Wall of sound ?

(Just kidding ;-))

[MostlyHarmless]

Yes, completely normal especially in Sport mode. You will also hear the exhaust crackle and pop when you accelerate and then let off the accelerator quickly.

Try watching a few review videos on YouTube. Most test drivers really get a kick out of it.

[383vett]

Probably a combination of the exhaust and piped in exhaust sounds.

[///Mposter]

I was surprised by it as well. I think the pressure is increased in the transmission in sport mode to get crisper shifting. I believe the rear differential bangs during the shifts . I thought it might be broken but nothing has happened in 7 years.
Recently I had my rear main seal done and I think they put in a different transmission fluid. Shifting in sport is quiet. Buttery smooth shifts all the time. I have not heard the bang at all since.

I miss the crisp shifts and my “banging through the gears”. But I guess that is what my single turbo coupe is for. X3 is my daily.

[BillD1953]

my M40i.....as I slow roll through the EZ PASS Maine Turnpike toll booths I like to press the "Sport Plus" mode....look to make sure the car has a clear path ahead...the adaptive suspension tightens up.... give it 3/4 - 4/4 throttle up to 70-75.........Love the sound !

75 comes real quick.......

[TxHornX3M40iGuy]

Originally Posted by BillD1953

my M40i.....as I slow roll through the EZ PASS Maine Turnpike toll booths I like to press the "Sport Plus" mode....look to make sure the car has a clear path ahead...the adaptive suspension tightens up.... give it 3/4 - 4/4 throttle up to 70-75.........Love the sound !

75 comes real quick.......

YES. I did this going under an overpass the other day and was grinning ear to ear.