The time is 7 a.m. The mist rises on the forested valley slopes of the Salzburgring. The thermometer struggles to reach nine degrees Celsius. It has been raining for hours. The wet track glistens in the dawn light. Challenging driving conditions for the new BMW i4 M50, which is getting its wake-up call in the pit lane garage ready for a drive. It is precisely these driving conditions and the challenging terrain of the racetrack that Charlie Martin really loves. The transgender racing driver (➜ Read also: A portrait of Charlie Martin on the Nürburgring) takes on her challenges with determination and curiosity and is more than ready to put the first pure electric sports car from BMW i and BMW M through its paces.
Focused on driving dynamics right from the start
The British professional racer gets some final tips and instructions from David Ferrufino, the project manager leading the development of the BMW i4 M50. One of the features to be tested, for example, is the Launch Control in Sport Boost mode, which gives maximum acceleration from launch. Ferrufino sees the all-electric vehicle (➜ Read also: All Electric Vehicle Types at a Glance) as offering the optimum blend of maximum dynamics and appropriate comfort in its class. He explains: “We paid the closest attention to precision and poise when developing the chassis, at the same time making sure it is fully suitable for everyday use and long-distance comfort. The DNA of the BMW i4 M50 is geared toward an even sportier feel, leaving nothing to be desired.”
Charlie Martin gets her first impressions of the key parts of the track and the ideal racing line during the practice lap. After that, the lights go green to try out the dynamics, traction and handling in practice. There are a few dry patches on the asphalt, but not for long. For the most part, the rain continues to increase the challenge for both car and driver.
Project Manager Ferrufino and professional racer Charlie Martin use five distinct sections of the track to give a rundown of the driving dynamics attributes that were the focus in developing the electric sports car BMW i4 M50, and how the Salzburgring perfectly showcases these.
Emco-Kurve – stiff body and perfect steering
“The battery case has to be stiff because of crash requirements. We took advantage of this when developing the vehicle’s driving dynamics, and joined the front and rear axles together very firmly using a front axle thrust field and a rear axle strut package,” explains Ferrufino. “This means the power flow is transferred very precisely and quickly from the front axle via the battery housing to the rear axle. The driver experiences a very agile vehicle that responds almost instantaneously to driver input. As a result, the vehicle drives as if on rails.”
Charlie Martin agrees that this steering precision is remarkable in every phase of the sharp S-curve after the pit exit, especially in the high limit range at the corner entry and exit. “I was impressed by how cleanly the vehicle handled the turn into a tight curve, despite the wet road. The BMW i4 M50 responds very precisely. There is no time offset between moving the steering wheel, the action of the suspension, and the tire reacting on the asphalt. The vehicle’s front axle gives impressive grip and lets me place the car where I want it without drift. You feel the benefits of this precise steering in the Emco-Kurve right from the start.”
Nockstein-Kehre – traction is key
When taking the Nockstein-Kehre bend that follows after a short straight (➜ Read also: How to find the racing line on any corner), the enormous traction potential combined with the high dynamics from the powertrain particularly brings out the BMW i4 M50’s sporty advantages, reveals Ferrufino.
“The stabilizer’s main purpose is to change the rolling stiffness of the axle on which it is mounted. The ratio of roll stiffness between the front and rear axles influences the car’s balance, especially its tendency to understeer or oversteer,” adds Charlie Martin, highlighting the BMW i4 M50’s exceptional traction in long corners. “I can play with the balance of the car in the Nockstein-Kehre. You take a lot of speed into the curve and can use the electric motor’s power very early on. The tire grip, which propels me forward out of the corner, gives me a good steering feel. The traction is so impressive, it feels like a magnetic carpet. That gives me the confidence to anticipate my driving line while utilizing the power generated by the electric motor – even in wet conditions. In fact, I can push the limits more than I ever thought possible and take even more speed out of the corner.”
Ostschleife – driving dynamics in all its facets
“If a vehicle is going to play fully to its strengths in the Ostschleife curve, it must offer perfect control in every driving situation – both through external influences such as rain, or road-specific obstacles such as dips and curbs,” explains Ferrufino. “Precise steering and an immediate transition from braking to acceleration, which the BMW i4 M50 provides, are crucial here. The driver experiences the lightness of the vehicle. It covers a very wide spread. At one end, it offers a very comfortable and quiet glide during everyday driving; at the other, it allows ambitious cross-country driving – or indeed a fast lap on the Salzburgring.”
Charlie Martin places particular emphasis on the rigidity of the chassis and suspension. “The car has to stay as steady as possible in this section, and not wobble or lean, because you need to have confidence in the chassis. This stability and composure gives you a very solid and accurate feel at the wheel when turning into the Ostschleife, which is approached in a long left-right combination at very high speed.”
Technical innovation under the vehicle hood as well as in its presentation: The animated 3D model gives you a comprehensive and fascinating insight into the technical inner workings of the BMW i4 M50. Now you can click your way virtually to the most important components that make the special electric driving dynamics possible.
Fahrerlager-Kurve – leading the way with e-drive
The major challenge in developing the electric BMW i4 compared to the combustion engine was to compensate for the 1,237 pounds (561 kg) of extra weight of the battery. Ferrufino saw this as both an opportunity and an exciting task that was solved with teamwork. “A very good example is using the battery as a central body element. The rigidity of the battery housing allows the power flow of the e-drive to be transmitted with precision and agility.”
Charlie Martin appreciates this agility. “The Fahrerlager-Kurve bend is an intense section of the track because you approach it at high speed, brake hard, then down-shift several gears. This can easily take the car off its line and you lose control. I don't have to worry about the downshift in the BMW i4 M50; just my line and braking. In the absence of the engine noise of a combustion engine to use as a reference, my senses are completely attuned to the feedback from the steering and chassis. As a result, I focus even more on the car’s setup and finding the perfect balance to maximize speed when entering the curve. Once again, the car surprised me because it felt so light on its feet.”
Schikane – accelerating to the ideal line
The Schikane, a chicane taken in a left-right-left combination, once again demands everything from the car and driver. “Many components in the BMW i4 M50 come together to create electrifying driving dynamics and master challenges like these in a sporty way,” Ferrufino explains. How does it do this? Among other things, a lower center of gravity and a strut package using the Adaptive M Sport suspension, with stiffness increased by 70 percent compared to the 3 Series. This features a revised axle geometry with 26 mm wider track on the front axle and 12 mm on the rear axle, the ARB-X near-actuator wheel slip limiter with 10 times faster torque control and a Gurney flap – a rear wing for increased additional downforce.
What makes the difference in the Schikane is the high acceleration out of tight corners, stresses Charlie Martin. “The car can handle precise directional changes while maintaining excellent grip on the front axle, more than I would have expected from an all-wheel-drive model. It is important to maintain the minimum speed between turns in the Schikane. You never have to shift back and forth between second and third gear with the BMW i4 M50; you have instant acceleration at your beck and call. This definitely gives the driver advantages over an internal combustion engine; the elasticity of the power delivery is something you just need to experience.”
Sharing the joy of driving
It’s 6 p.m. and the test drive is over. The racetrack gleams in the pouring rain under the light of the pit lane as the car glides into the dry garage. The project manager listens with intrigue to Charlie Martin’s impressions of her drive.
This is a very special moment for Ferrufino: “The greatest satisfaction for a project manager, and also for BMW as a whole, is to be able to give joy to customers and fans with our products that we have spent three, four or even more years developing. Experiencing the test drive and direct feedback from a passionate racing driver like Charlie Martin is a special feeling.”
When the last floodlights go out on the racetrack, Martin heads off again, her next engagement, the next race, beckons. She gives the BMW i4 M50 a lingering final look as she bids farewell. Very quietly: You can define driving pleasure, but sometimes there’s simply no need to look for the words. A facial expression says more than a thousand words.
Author: Markus Löblein; Photos: Yannick Wolff; Video: Yannick Wolff, Patrick Zander