Oom Pah Pow!: Affalterbach Takes the Gloves Off

AMG'S MIDDLEWEIGHT SUV BRAWLER HITS HARD

- JONNY LIEBERMAN

Mercedes-AMG surprised no one this past November when it took the wraps off the two most powerful SUVs AMG makes: the three-row GLS 63 and the two-row GLE 63 S, the latter being the subject of this review. It makes 603 horsepower and 627 lb-ft of torque, plus has hybrid assist.

Fast-forward four months, and I’m cruising west on the Pacific Coast Highway through Malibu behind the wheel of a blue GLE 63 S. I’m not going too much over the speed limit, 70 mph or so, and there’s a little blue square on the dashboard telling me the big boy is only using four of its eight cylinders. Moreover, another digital readout is letting me know the electric motor is sending power to the transmission. What sort of an AMG is this?

A complex one, it turns out. The GLE 63 S (and the mechanically identical GLS 63) is the first AMG to feature Mercedes’ 48-volt mild-hybrid V-8 engine, codenamed M176. This 4.0-liter twin-turbo engine replaces the old M157 5.5-liter twin-turbo V-8. The 48-volt V-8 is smaller, lighter, (maybe) more efficient, and most important for AMG, makes more power and torque. Like the M256 inline-six, the M176 is beltless and uses both an electric water pump and AC compressor, and both the starter and the alternator are replaced by the integrated starter-generator, or ISG. In addition to starting the thing up and supplying juice to the various onboard electric and electronic systems, the ISG can also supply 21 horsepower and 184 lb-ft of torque to the driveline.