The GLS has two new (and rather complex) engines, a 3.0-liter turbocharged inline-six making 362 horsepower and 369 pound-feet of torque and a 4.0-liter twin-turbo V8 making 483 horsepower and 518 pound-feet of torque. Both are paired with a 48-volt mild hybrid system Mercedes calls EQ Boost, increasing fuel efficiency and performance. Both systems work the same way. A small electric motor is placed between the engine and transmission and performs a variety of tasks, from smoothing out shifts to mitigating turbo lag by supplying a bit of low-end power while exhaust gasses spool the turbos. It even powers the accessories, meaning these engines are beltless. That makes them more compact, but it also means there's less parasitic loss from accessories such as the A/C compressor. This is the first time the system is available with a V8 engine, but expect the powertrain to expand to much of Mercedes' lineup over the next few years. Like in those other cars, th...
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