How Driving the GT XX Around the World Is Helping Mercedes Out-Tech Tesla

The record-breaking AMG GT XX wasn’t designed as a show car but to torture-test advanced tech destined for production Mercedes EVs.Angus MacKenzieWriter

ManufacturerPhotographerSep 19, 2025

Mercedes-Benz has a long tradition of record breaking and of competing at the highest levels of motorsport, such as Formula 1. But while some automakers are content to consider record-breaking and racing as little more than marketing tools, Mercedes-Benz has also used competition to prove out technologies that may ultimately appear in its production cars, as well as to sharpen the reflexes and instincts of its engineers.

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So, the Nardò record run that saw the Mercedes-AMG GT XX concept drive the equivalent distance of a lap around the world in less than eight days, smashing 25 electric vehicle speed and distance records, wasn’t just an expensive publicity stunt. It torture-tested advanced technologies that will be used in the coming generation of high-performance electric-powered Mercedes-AMG models. Here are some of those features.

Battery Management System

The AMG GT XX previews the high-performance liquid-cooled battery pack that will be at the heart of the new AMG.EA electric vehicle architecture set to underpin the production version of the GT XX, as well as a high-performance electric AMG SUV, along with other electric AMG models yet to be announced. The innovative battery features thin tubular cells immersed in a nonconductive oil.

This design allows the cells to stay at their optimum operating temperature. “Battery cells are like human beings,” AMG.EA chief engineer Oliver Wiech said. “They don’t like it being too cold, or too hot.” That’s hardly news to any automotive battery engineer. The clever part about the AMG.EA battery management system is that Mercedes engineers have developed an algorithm that can figure out what’s going on inside the battery’s cells in real time and thus allow the car to more effectively control temperature and keep the battery in its happy place.

Gregor Gruber, project lead of E-drive at Mercedes, says the algorithm is based on data from sensors that measured changes in potential, temperature, and voltage within actual cells, first in the lab, and then in prototypes, as they were put through a series of drive profiles at different ambient temperatures. “We built a mathematical model that runs on the car while it’s driving, while it’s charging, creating what we call virtual sensors,” he said. “Physical sensors on the car feed that model, and the model then spits out the data for each individual cell regarding the state at their core.”

For the record run, this data was fed into a simulation tool developed by engineers at Mercedes-AMG High Performance Powertrains (HPP), the British-based engineering shop that builds the fiendishly complex hybrid powertrain for the Mercedes-AM Petronas F1 cars. “The drive cycle was very aggressive,” Markus Dittmann, E-drive project lead at HPP, said, “and we needed to understand how each cell was behaving throughout the whole challenge.”

For almost eight days, both of the AMG GT XX cars used in the record run were driven under maximum acceleration to 186 mph and then cruised at that speed for 23 to 55 miles in ambient temperatures as high as 95 degrees Fahrenheit, before coming back into the pits and being hooked up to an ultra-fast charger that sent energy into the battery at an average charge rate of 850 kW.

It was a duty cycle with which most other EV batteries would be unable to cope, but the AMG.EA battery pack delivered peak performance throughout. “We had such good thermal management that we didn’t get any derating,” Wiech said. “We didn’t get to a place where we had to limit power.”

Ultra-Fast Charging

Key to the AMG GT XX’s record-breaking pace was careful management of energy flows. The car’s predictive performance management system, a version of which will appear in the production model, would tell drivers on their in-lap, via a system of LED lights and onscreen graphics, exactly when to lift off and coast, and then when to engage maximum regenerative braking.

In most EVs, regenerative braking maxes out at 0.3 g. The AMG.EA architecture enables regenerative braking of 0.6 g. As we saw while riding along on a demonstration run after the record attempt, the regenerative braking window was calculated to send the optimum amount of energy back into the battery—about 920 kW, on average—while ensuring the car came to a halt right in front of one of the two ultra-fast chargers Mercedes-Benz installed at Nardò specifically for the event.

These megawatt chargers, dubbed Hypercharger 1000 and developed in conjunction with European specialist Alpitronic, are prototypes of chargers that will be installed at AMG-specific charging stations in Europe. They are liquid-cooled and can transmit currents of up to 1000 amps via a liquid-cooled CCS cable.

During the record run, the battery was typically recharged from 20 percent state of charge to 60 percent before the car was sent back out on track. Staying in the car as it was hooked up to one of the Hypercharger 1000s after our demonstration run, we saw the battery go from 23 to 36 percent in about a minute, with an initial charge rate of 832 kW rising to 956 kW.

Central Coolant Hub

“Why is cooling important?” asks Alessandro Mezzogori, the engineer responsible for the cooling development and testing of the AMG.EA architecture. “Because it’s about continuous performance.” The reason the AMG GT XX could travel so far, so fast, in the heat of a southern Italian summer, Mezzogori explains, was because its three axial-flow e-motors, power electronics, and high-performance battery pack could be kept cool. And key to ensuring the AMG.EA’s powertrain temperatures were kept under control was its central coolant hub.

Located at the front of the car, just to the left of the single electric motor and power electronics for the front axle, the central coolant hub combines three high-performance cooling pumps and various sensors and valves into a single structure. The hub not only connects all components requiring cooling but also links to the main radiator and the two radiators in the front wheelwells. Valves allow partial cooling circuits to be switched on or off as needed.

The central coolant hub can ensure maximum cooling to the motors, drive units, power electronics, and battery during high-load driving and at elevated ambient temperatures, as during the record run at Nardò, but it can also deliver targeted and efficient cooling of individual components. That means that unlike most other EVs, which typically need to reduce their powertrain outputs to keep them cool, the AMG.EA powertrain can always deliver full power.

Another important element of the AMG.EA’s cooling system is the passive underbody cooling plate at the front of the chassis. Developed in conjunction with Mercedes-AMG High Performance Powertrains, the concept was initially tested in the EQXX concept. The cooling plate is so efficient, the flaps of the radiator air control system can remain closed over long periods to improve energy efficiency and reduce aerodynamic drag.

Plasma Actuator Aerodynamics

The production version of the AMG GT XX will look slightly different from the Nardò record-breaker. Among other things, it will have a taller roofline and a slightly less raked windshield, as well as a steeper backlight with a glass rear window. The AMG GT XX was styled by Mercedes-Benz designers to package the production-ready AMG.EA hardware underneath bodywork that not only hinted at how the production car would look, but also to be as aerodynamic as possible. Then it was handed over to the three-pointed star’s aero experts for fine-tuning.

The AMG GT XX thus bristles with the usual state-of-the-art aero tools such curtains to direct air past the front wheels, venturis on the floor to increase downforce, and an extended diffuser at the rear. But it also features clever tweaks such as the passive aero wheel covers that are vented differently front to rear—at the front to get air into the wheelwells and at the back to get air out of the rear wheelwells, thus increasing downforce on the rear axle without the need for a wing—and aero-enhanced exterior rearview mirrors.

All these add up to an impressively low claimed drag coefficient of 0.19. “At 186 mph, 83 percent of the powertrain’s energy is being used simply to overcome air resistance,” Gustavo Estrada, director of aerodynamics at AMG, said. “One point of aero improvement [the third decimal place on the Cd number] equals 0.6 mile improvement in range, and we got five points alone by working on the external rearview mirrors.”

But the coolest, and in terms of future Mercedes-Benz production cars, perhaps the most profound aero technology honed for the AMG GT XX was one that, in the end, wasn’t used for the record attempt: plasma actuators.

A technology currently used on aircraft and wind turbines, plasma actuators consist of thin metallic plates with two asymmetrically arranged electrodes separated by an insulating dielectric layer and can be attached flush to various components. Applying a high-frequency alternating voltage between the electrodes leads to the formation of an electric field and weakly ionized air, or plasma, near the plate. The ions are accelerated by the electric field, and the resultant particle-on-particle collision leads to a momentum transfer from the ions to the surrounding neutral air, helping it flow more efficiently.

A plasma actuator, which can be invisibly embedded under the body surface, can thus create the same targeted airflow characteristics around a car’s bodywork as with a spoiler or a sharp edge, but without an increase in drag. And it requires no mechanical or hydraulic parts—the airflow characteristics can be changed simply by switching the plasma actuator on and off.

Mercedes-Benz wind-tunnel-tested plasma actuators mounted near the rounded rear corners of a full-size model of the AMG GT XX, becoming the first automaker to seriously evaluate the technology. So, why weren’t the plasma actuators, which delivered the same aerodynamic benefits as sharp corners at the trailing edge of the rear fenders of the GT XX, used on the record car? “We found that at speeds over 120 mph their effect became weaker,” explains aerodynamics engineer Philipp Dörr. But Mercedes is clearly interested in exploiting the technology in its road cars. “Plasma actuators running down the A-pillars of the G-Class, for example, would really improve its aerodynamic efficiency,” Dörr said.