What happens when Mercedes adds a hybrid drivetrain to its largest sedan?
With all due respect to the Audi A8, Lexus LS 460, and even the hard-charging BMW 750i, the Mercedes-Benz S-Class is arguably the top dog of the full-size luxury sedan world. Doubters need only spend a few minutes in the heated massaging front throne (“seat” simply doesn't do it justice) of an S-Class for its unsurpassed mix of comfort, capability and technology to make clear why it's the benchmark.
In our humble opinions, the 2009 S-Class left little to be desired. If we had our druthers, we'd make it a little less thirsty and a little more affordable. The response from Stuttgart? “Done and… done.” Enter the 2010 S400 Hybrid, a new S-Class with an innovative gas-electric V6 power train that undercuts the V8-powered S550 by nearly four grand. Can this sybaritic fuel sipper still deliver the goods? And is it really green, or just a cheap grab at eco cred?
Photos courtesy of Mercedes-Benz.
#10. The S400 is a different kind of full-size luxury hybrid
Lexus beat Mercedes to the hybrid flagship punch with its 2008 LS 600h L. Packing both a 389-hp V8 and a 221-hp electric motor, the hybrid LS had a clear mission: seek and destroy V12-powered sedans using V8 fuel economy. Although a wonderful super-luxe saloon in its own right, the LS 600h L failed to conquer 12-cylinder U-boats like the Mercedes S600 and BMW 760i. Instead of using hybrid technology to pump up an already potent eight-banger, Mercedes has sliced two cylinders from the equation and added a relatively small electric motor.Page 2
#9. This gas-electric Benz is a “mild” hybrid – in more ways than one
The S400 is powered by a 3.5-liter V6 capable of 275 hp and 258 lb-ft. of torque. It's aided by a 20-hp battery-powered electric motor. Unlike the Toyota Prius or Honda Insight, the S400 can't run in electric-only mode, hence the “mild hybrid” designation. Fuel savings could also be considered “mild.” With an EPA estimated 19 mpg/city and 26 mpg/highway, the S400 delivers 26% percent better fuel economy than a comparable S550. Translation? About four additional mpg – good enough to avoid the gas-guzzler tax. The S400 scores a few more green points for its use of recycled and renewable materials, including coconut fibers in the seatbacks.Page 2
#8. The big news is the battery
As clean-car aficionados know, high-mileage hybridization and electric driving are all about better batteries – compact, quickly rechargeable and durable. The S400 is the first mass-production car packing a lithium-ion battery – the same technology found in consumer electronics like laptops. (The low-volume Tesla Roadster also uses one.) The S400's shoebox-sized 32-cell, 120-volt lithium-ion battery is cleverly stashed in the engine bay where it can't eat away at the sedan's voluminous rear seat room or trunk space.Page 2
#7. Want to know how regenerative braking works? Let the S400 show you!
Let's face it: moderately efficient hybrids are as much status symbols as they are earth-savers. With a few twists of the S400's COMAND system rotary knob, the eight-inch sat-nav display is transformed into a full-color, bird's-eye schematic of energy flow between the car's gasoline engine, electric motor, battery, and wheels. Dip the throttle and watch the dotted lines snake from the engine and motor to the wheels; press the brake and watch them flow from the wheels to the battery, indicating the regenerative braking that recharges the lithium-ion battery. Nifty… but pointless. Worse still is a split-view “Fuel Consumption Indicator” bar graph that requires an advanced engineering degree to decipher.Page 2
#6. If only the hybrid system was as seamless as the nifty diagram…
The use of a lithium-ion battery might qualify the S400's hybrid system as “cutting edge,” but there are definitely some sharp corners that could use filing. Chiefly, the system's stop-start function, which turns the gasoline engine off below nine mph when braking, then restarts it when the brakes are released. Fire up the S400, step on the gas and there's a one-Mississippi pause followed by a shimmy-shake detectable through the throttle. It's not a deal breaker, but it's a bit of a disappointment given the refinement and engineering finesse traditionally synonymous with the S-Class.Page 2
#5. Can a V6 and a small electric motor really be enough?
Our answer is “definitely.” Although the electric motor adds a nominal 20 hp, its 118 lb-ft. of torque come in handy when launching this 4,474-pound sedan from a stop. The S400's combined output of 295 hp and 284 lb-ft. of torque falls well short of the V8-powered S550 (382 hp and 391 lb-ft., respectively). But on the road, the S400 has more than enough passing power without ever feeling strained. Steering is perfectly linear and the air suspension with adaptive damping snuffs out excessive body roll and front-end dive. Mercedes clocks the S400's zero-to-60 time at 7.2 seconds (compared with the S550's 5.4 ticks), but an S-Class isn't built for naught-to-60 scrambles.Page 2
#4. The S400 cabin actually makes sitting in L.A. traffic a treat
No one relishes a long commute… unless they drive an S-Class. Slide into the buttery soft embrace of the 14-way power heated front seat; dial in precise shoulder, lumbar and side pneumatic supports; choose one of four massage options; and enjoy the best long-distance conveyance this side of a Cessna. A simple row of chrome switchgear that is as pleasing to the eye as it is the fingertips adorns the generous swath of burl walnut across the console. Show it all off under adjustable fiber-optic ambient lighting in white, amber or ice blue. Electronically, the COMAND interface is extremely intuitive, and the 15-speaker Harmon Kardon surround sound system readily accepts MP3 players.Page 2
#3. It's safety gadgets a-go-go!
Other than the hybrid power train, the biggest changes to the 2010 S-Class range are a host of high-tech safety features that debuted in the 2010 E-Class, including a Pre-Safe Brake system that can automatically apply 100 percent braking power to prevent a crash; Attention Assist, which monitors steering input and 70 other driving parameters to detect signs of driver fatigue; and Night View Assist Plus, which uses a windshield-mounted infra-red camera to extend visibility by 500 feet and highlight pedestrians in the path of travel. Exterior design tweaks include a revised front grill and bumper, and LED taillights that do away with the previous model's body-color-matched inset pieces.Page 2
#2. There's some added incentive to drive a little greener
Hybrid models typically carry a price premium over their gasoline-only counterparts. Not the S400. Its base MSRP of $87,950 is a shade under the $91,600 asking price for an S550. Of course, the savings is easily gobbled up by any number of enticing “value-added" packages. Our silver S400 test car came with a $4,950 premium package featuring the aforementioned heated, ventilated and multi-contour massaging front seats; bi-xenon adaptive headlamps; LED daytime running lamps; and rearview camera with parking assist. Other packages include a $2,990 rear-seat comfort bundle and a $5,800 sport wheels and body styling package.Page 2
#1. There are definitely greener pastures ahead
The S400 is a first stab at hybridizing the three-pointed-star's flagship sedan and there is definitely room for improvement. The S400 is also one of a growing portfolio of Mercedes vehicles aimed at the “environmentally oriented buyer.” The clean diesel BlueTec vehicles offer better mileage; unfortunately, high diesel prices have limited their appeal. This summer, Mercedes will offer a limited leasing program for its hydrogen-electric F-Cell car. The company has also promised an electric version of the stunning SLS AMG supercar. As for the S-Class, it only became the benchmark by consistently overachieving. If the premium luxury hybrid is indeed a viable niche, we predict future gas-electric S-Class models will be pinnacles there too.