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What does the sport differential do, how does it act/react?

Discussion in 'F25 X3 (2010-present)' started by bernadine, Jan 3, 2021.

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    We currently have a 2020 X3 M40i and a 2020 X4 M40i. This is our third X3 and our fourth, overall BMW. We have also had several Audi quattro's -- over a period of many years. In fact, we've even had one Acura TLX w/SH-AWD.

    I wrote a letter to BMW (email) and they responded in two days! I figured I wouldn't hear from them, so that was a pleasant plus.

    I asked two (maybe technically three) questions, one about iDrive 7 and Alexa integration and traffic sign recognition integration with ACC. The other question I asked was if the optional Sport Differential provided a function similar to an Audi quattro's sport differential and Acura's SH-AWD. I was careful to define "torque vectoring" and to explain that I was not speaking about any brake-based torque vectoring.

    I asked if I entered a curve (e.g., a "left curve") at speed and some understeer was present if the outside rear wheel had additional torque sent to it to help mitigate the understeer.


    On both Audi and Acura vehicles this is exactly what happens and, on the Audis, the "degree" of torque vectoring can be set at "comfort", "automatic", or "dynamic" in the MMI menu system. On a quattro so equipped, Audi also includes brake-based torque vectoring on the front wheels, meaning in my example above that the rear differential would increase the power to the rear outside wheel (in my example the right rear wheel) and if necessary, the left front brake would be applied to further mitigate understeer.

    The response from BMW was that Amazon's Alexa is NOT available in North America and they are sorry and hope that doesn't reduce my enjoyment of the vehicle. Frankly, it really doesn't but the annoying "Hello BMW" assistant is seemingly hampered since she can't even raise and lower the cabin temp or turn the heated seats on and off etc. My 2012 Acura could do these things and wasn't always waking up asking if it could help me like the BMW assistant does.

    On the issue of the traffic sign integration with the ACC, they said that feature is only available on certain versions of the iDrive 7 and/or only in Europe, but that the software IS UPDATED from time-to-time and new features are added. They did caution me that they did not have access to the information regarding if and/or when such an integration might occur, if ever. My BMW genius at my dealer says the hardware/software that is on the car already seems to suggest the issue is software NOT hardware, but that they have no pipeline into BMW to determine when or if such a feature is planned for the 2020 BMW X3/X4 with iDrive 7.

    On the issue of the Sport Differential, they punted. They simply said I should ask the dealer about this. The BMW genius doesn't seem to know or doesn't seem to understand the notion of torque vectoring. The most I can get is that it is sort of like "Pos-i-traction" -- a term used by GM a long time ago. The torque-sensing feature and the ability to shift torque to the "outermost" wheel in a cornering situation is a question that both Audi and Acura addresses in their owner's manuals. I can find nothing in my X4 M40i's owners manual that addresses even the existence of the "Sport Differential" as an optional feature. This seems odd, after seeing both the Acura and Audi manuals (the Acura had a graphical display of the torque shifting under hard cornering and acceleration that showed where the torque was being routed amongst the four wheels.)

    Other than on the window sticker, there is no indication that the sport differential even exists in any BMW literature.

    Why is this kept such a "state secret" on BMWs? And, does the BMW sport diff behave in a similar fashion to "quattro" and "SH-AWD"?

    BTW, my X4 M40i is a fantastic car, I love it. I just wish there was a source (the owners manual leaps to mind) to find out about the various features.

    Thanks for helping.

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