Approximately two years ago, we reported a rumor that BMW intended to develop a full M version of its all-new, all-electric BMW i4 sedan, and now the company itself has all but confirmed such a car is already in development with news of a new four-motor prototype. Unlike the current BMW M-tuned i4 M50 (which falls under BMW’s mid-level M Performance banner), this new i4 is aiming for a performance level to actually rival, or even eclipse the gas-powered BMW M3 and M4.
Widebody BMW i4
The new prototype is said to be part of BMW M GmbH’s 50 year celebration, and to serve as a clear direction for the M brand in an all-electric world. Building on the i4 M50 performance model that was introduced this year, BMW has taken that car’s body and widened the front wheel arches, which permit the integration of specifically manufactured high-performance front and rear axle designs. Current i4 M50s already wear little fender flare extensions on their rear wheel arches; this prototype clearly extends that thinking.
The front of the i4 M prototype gets an adapted strut adopted from the BMW M3 and M4 models that offers high torsional rigidity for dynamic driving conditions. The positioning of the car’s radiator units has also been remapped for a higher performance application based on the M division’s expertise on its other performance cars. If you’ve ever looked at a X3 M, for example, it’s radiator city behind the front clip.
All-Electric, Each-Wheel Drive
Each corner of the car gets its own motor, which means BMW is figuring out its first-ever four-motor M xDrive all-wheel drive system to manage all the torque and power. “Within milliseconds, the power and torque of the spontaneously reacting electric motors can be dosed so precisely that the load demand signaled via the accelerator pedal can be realized at a level of dynamics that is unattainable using conventional drive systems,” BMW says.
“Electrification opens up completely new degrees of freedom for us to create M-typical dynamics,” says Dirk Häcker, Head of Development at BMW M GmbH. “And we can already see that we can exploit this potential to the maximum, so that our high-performance sports cars will continue to offer the M-typical and incomparable combination of dynamics, agility and precision in the locally emission-free future.”
Torque In Milliseconds
BMW has also described the highly integrated control unit for managing all four motors in real-time, calculating ideal vehicle settings based on real-world conditions and driver inputs. “The ideal power transmission to the road is calculated within milliseconds from the values for the accelerator pedal position, steering angle, longitudinal and lateral acceleration, wheel speeds and other parameters. The signals for this are transmitted just as quickly and directly via a multi-plate clutch and differentials to the four motors, which are able to implement them immediately and precisely.”
This results in better performance in adverse weather as well as higher cornering speeds in spirited driving. Specifically, they claim to have ironed out issues with understeer already by increasing the drive torque for the outside rear wheel in parallel to the steering angle. BMW says all of this prototype road testing should deliver a car that’s true to the BMW M division legacy of offering a “linear build-up of drive power and lateral dynamics that permits controllable handling right up to the limits.”
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