AMG brings a flat-plane V8 back to its biggest SUVs
The V8 is not dead at AMG, it just got better
Mercedes-AMG has fitted its GLE 63 and GLS 63 with the M117 Evo, a new twin-turbo V8 that draws directly on motorsport practice rather than following the plug-in hybrid path most of the segment has taken. The engine uses a flat-plane crankshaft, a configuration more commonly found in race cars than large performance SUVs, and produces 450kW on its own before a 48V mild-hybrid adds a further 17kW to bring the combined figure to 468kW.
Both models reach 100km/h in under four seconds and are limited to 280km/h. Those numbers are what the segment expects. The more considered part of the story is what AMG chose to leave out: a plug-in hybrid system. At a moment when the industry has spent years engineering heavier, more complex powertrains in the name of emissions figures, AMG has moved in a different direction.
What the M117 Evo changes under the bonnet
The defining engineering decision in the M117 Evo is its flat-plane crankshaft. A flat-plane crank fires the cylinders in a more evenly distributed pattern than a conventional cross-plane V8, reducing vibration at higher engine speeds and producing a sharper, higher-pitched intake character that cross-plane designs physically cannot match. AMG has paired this architecture with revised fuel injection, new air intake and exhaust ports, a reworked camshaft, and new turbocharger housings. The base engine output is 450kW and 850Nm, with the 48V mild-hybrid contributing its 17kW during acceleration.
New bodywork and a more capable chassis underneath
The exterior gets a redesigned front end on both models, with a bespoke AMG grille, enlarged air intakes, and updated lighting. Wheel sizes increase to 22 inches on the GLE 63 and 23 inches on the GLS 63. Underneath, an active ride control system reduces body roll during cornering, reinforced driveshafts handle the higher torque output, and the GLS 63 gains a rear axle locking differential for sharper direction changes at higher speeds.
Why AMG is stepping away from plug-in hybrid
AMG's decision to skip plug-in hybrid for this generation of the GLE 63 and GLS 63 is not a default outcome; it is a considered one. A PHEV powertrain adds significant weight to any vehicle, and in an SUV that already carries mass, that weight works against the driving character AMG is selling. The counterargument has always been that a PHEV offers an all-electric mode for urban use and that the emissions figures on paper justify the added complexity. AMG is clearly less persuaded by that case than some of its rivals.
Instead, the 48V mild-hybrid takes a supporting role rather than a leading one, contributing boost during acceleration without adding the weight or charging infrastructure requirements of a full plug-in system. Pricing for both models has not been confirmed. Both the GLE 63 and GLS 63 are expected to reach European markets later in 2026.
AutoNext Take
AMG fitting a flat-plane crankshaft to a large family SUV is the kind of engineering decision that deserves more attention than it usually gets. A flat-plane crank is not a packaging solution or a weight-saving measure: it is a choice about how the engine sounds and responds at the top of its rev range. That AMG thought it worthwhile to engineer that level of character into what is fundamentally a school-run vehicle says something about how seriously the division takes its identity, even as the broader Mercedes portfolio accelerates toward electrification.
The rejection of plug-in hybrid is the headline underneath the headline. It is a bet that buyers who choose the GLE 63 or GLS 63 want the experience of a performance engine rather than the convenience of a short electric range. Given that AMG's customers have historically made exactly that choice, it is probably the right read of its market.
