2027 Mercedes-AMG GLS 63 Engine, Performance and Exhaust Sound

The Mercedes-AMG GLS 63 4MATIC+ has always been one of those vehicles that seems to ignore the laws of physics. It offers the comfort and space of a luxury sport utility vehicle while delivering the kind of acceleration that can surprise many sports cars. For 2027, Mercedes-AMG has taken that formula even further with major updates under the hood, giving its flagship performance sport utility vehicle more character, sharper responses, and a completely new soundtrack.

At the heart of the new model is an extensively revised 4.0-liter twin-turbocharged V8 engine. While the displacement remains familiar, this is far more than a simple carryover powerplant. Mercedes-AMG engineers have redesigned key internal components to improve performance, efficiency, and responsiveness while meeting increasingly demanding emissions standards around the world.

One of the biggest engineering changes is the move to a flat-plane crankshaft. Previous AMG V8 engines used a traditional cross-plane crankshaft, producing the deep rumbling exhaust note enthusiasts have loved for years. The new flat-plane design changes the personality of the engine completely. It revs more freely, responds more quickly to throttle inputs, and creates a sharper, higher-pitched exhaust note that sounds much closer to an exotic supercar than a traditional luxury sport utility vehicle.

The updated V8 produces 603 horsepower and 627 pound-feet of torque. Mercedes-AMG has also paired the engine with a 48-volt mild hybrid system featuring an Integrated Starter Generator. During hard acceleration, the electric motor can briefly contribute an additional 23 horsepower and 151 pound-feet of torque, helping the GLS 63 launch even harder while improving response at lower engine speeds.

Power continues to flow through the AMG Speedshift 9-speed automatic transmission before reaching the fully variable AMG Performance 4MATIC+ all-wheel-drive system. The combination allows the large luxury sport utility vehicle to put its immense power to the pavement with remarkable confidence, regardless of road conditions.

Despite weighing well over 5,600 pounds, the 2027 GLS 63 delivers performance figures that would have seemed impossible for a vehicle of this size just a few years ago. Mercedes-AMG estimates a 0 to 60 miles per hour sprint of only 3.9 seconds. Some independent testers even believe real-world numbers could be slightly quicker based on previous AMG performance results. Top speed reaches 174 miles per hour when equipped with the optional AMG Driver’s Package.

Straight-line speed is only part of the story. Mercedes-AMG has refined nearly every aspect of the driving experience. The updated AMG Ride Control+ air suspension works together with Active Ride Control to reduce body roll while maintaining impressive ride comfort. Rear axle steering and the electronically controlled rear limited-slip differential further improve stability and agility, making the GLS 63 feel considerably smaller than its actual dimensions suggest.

Perhaps the biggest surprise for enthusiasts will be the exhaust sound. The switch to a flat-plane crankshaft transforms the engine’s voice into something entirely different from previous AMG V8 models. Instead of the familiar low-frequency rumble, drivers are treated to a sharper, more exotic tone that builds into an aggressive mechanical scream as engine speed rises. Downshifts deliver crisp crackles, while acceleration produces a sound that is unmistakably inspired by motorsport.

Mercedes-AMG has also equipped the GLS 63 with an updated AMG Performance exhaust system featuring electronically controlled exhaust valves. The character of the exhaust changes depending on the selected driving mode. Comfort mode keeps the system relatively quiet for everyday driving, while Sport and Sport Plus progressively open the valves to allow a louder, more emotional soundtrack. The result is an exhaust that adapts to both relaxed cruising and spirited driving without sacrificing refinement.

Throttle response has also improved thanks to revised turbocharger components, updated intake and exhaust ports, optimized fuel delivery, and a redesigned compressor wheel. Together, these changes allow the engine to build boost more quickly, giving drivers immediate acceleration whenever they press the throttle.

Although stricter global emissions and noise regulations continue to challenge performance manufacturers, Mercedes-AMG has found an impressive balance between environmental responsibility and driving excitement. Rather than simply reducing noise, engineers focused on creating a more engaging engine character that feels modern while preserving the emotional connection drivers expect from an AMG model.

The 2027 Mercedes-AMG GLS 63 4MATIC+ proves that high-performance sport utility vehicles continue to evolve. With its redesigned V8 engine, advanced hybrid assistance, quicker responses, improved chassis technology, and dramatically different exhaust note, it represents one of the most significant mechanical updates AMG has introduced in years. It remains a luxurious family vehicle, but now delivers an even more thrilling experience every time the engine comes to life.