2011 Infiniti M56 vs. 2010 Mercedes-Benz E550 Comparison Test

2011 Infiniti M56 vs. 2010 Mercedes-Benz E550 Comparison Test

  • Full Review
  • Pricing & Specs
  • Road Tests (2)
  • Comparison (1)
  • Long-Term

2010 Mercedes-Benz E-Class Sedan

(5.5L V8 7-speed Automatic)

2011 Infiniti M56 vs. 2010 Mercedes-Benz E550

  • Comparison Test
  • Second Opinion
  • Top 15 Features
  • Final Rankings and Scoring Explanation
  • 2010 Mercedes-Benz E550 Specs and Performance
  • 2011 Infiniti M56S Specs and Performance

You won't find a luxury sedan from every prefecture in Japan and province in Germany in this test — just the 2011 Infiniti M56S and 2010 Mercedes-Benz E550.

But this isn't some random pairing of business-class sedans. We're like sommeliers here at Inside Line, and this evening we bring you the two midsize luxury sedans with the largest available V8 engines (well, aside from the E63 and Cadillac CTS-V). The Infiniti M56S and Mercedes-Benz E550 have a combined 11 liters of engine displacement. If you were a good old boy, you'd know that's 672 cubic inches.

Even if you're not good or old, you learn the simple pleasure of low-end torque every time you plant the throttle in the 2011 Infiniti M56S and 2010 Mercedes-Benz E550. These sedans move out with the cool authority of corporate executives cracking the whip on the backs of middle-management slackers.

The Mercedes E-Class is a classic choice if you're looking to assert yourself and still drive around in something civilized. And the E550 just so happens to have won our last comparison of midsize V8 luxury sedans.

The 2011 Infiniti M56S, meanwhile, is an upstart angling for a promotion. This new M promises more sophistication and interior room than the outgoing M45. Yet it's also trying to make its mark as a sport sedan in a class that's rapidly losing interest in sport sedans, especially when it carries the package of equipment that makes it an S model. It's a lot to accomplish in one car, and an especially big task when you're up against a luxury sedan that always seems to have all its ducks in a row.

More Alike Than Different
Though the 2011 Infiniti M56 and 2010 Mercedes-Benz E550 couldn't look more different on the outside, we're struck by the similarities in their basic specifications. They're within 3 inches of each other in overall length, and they ride on nearly the same wheelbase and track. They weigh within 50 pounds of each other, which is to say they tip the scales at 2 tons apiece.

What the Infiniti's soft curves can't quite hide is that it's nearly 5 inches narrower across the shoulders than the square-jawed Mercedes. It's a consequence of the fact that the M56 is based on a Japanese-market Nissan designed to pack into urban landscapes with millions of people and apartment blocks.

So the Infiniti M56's cabin ends up feeling more snug and intimate than the Benz's open, airy quarters. It has a sporty identity, but there's a warmth to this design not seen in previous Infinitis. Though the M56 falls short in features, it cedes no ground to the E550 in overall cabin quality. Space is still more than ample in both, though, so it's a matter of your taste.

Mercedes Has More Stuff
However, this comparison test will indeed be won in the cabin. Amenities count for a lot in luxury sedans; if they didn't, we'd all be driving around in a stripped-down 3 Series. So for this comparison test, we've made the evaluation of features account for 20 percent of the final scores. The 2010 Mercedes-Benz E550 has a big advantage here — not because it has more shoulder room, but because it has more stuff.

You'd absolutely expect the E550 to have more because it costs $71,955 versus just $64,435 for our 2011 Infiniti M56S (relax, pricing is weighted 20 percent, too). But it's not that simple, because the Benz comes with key items that you can't get on the Infiniti for any price.

Airbags are a biggie. Maybe you don't absolutely need the E550's driver and front-passenger pelvic airbags, plus a knee airbag, but you'd sure appreciate them in a major front-end crash. And with the Mercedes' standard TeleAid system, you'll probably get help fast, too. The E550's optional night-vision system, which delivers its clear black-and-white images to the central display, is also useful at helping you spot weird neighbors walking their dogs in the wee hours.

We also like that the 2010 E550 offers both a power-operated trunk lid (as an option) and a 60/40-split rear seat that folds perfectly flat. Every luxury sedan should offer these conveniences. Only coupe drivers are allowed to pretend that utility doesn't matter.

Probably the most critical feature in the Mercedes-Benz E-Class, though, is the little button on the console for its driver-adjustable adaptive damping system. The Infiniti M56S doesn't have one of these, and it rides stiffly on its 20-inch wheels no matter what. The E550, meanwhile, is easygoing and composed.

Open the Hood
Maybe you think the 2011 Infiniti M56S should just pack up and go home now. But owning a midsize luxury sedan is about more than counting up features and fussing over the ride. Sometimes it's just you in the car and you're just driving, and in these moments, the M56S is an interesting counterpoint to the overly refined E550.

Different personalities emerge as soon as you get on the throttle.

The 5.5-liter V8 in the 2010 Mercedes-Benz E550 is ridiculously smooth in its delivery, and you can feel the power building with the predictability of a linear equation. The Benz V8 is also quite at ease at high rpm. So even though its 382 horsepower peaks at 6,000 rpm, this 5.5-liter is happy to sustain its output all the way to the 6,400-rpm redline. Torque plateaus at 391 pound-feet from 2,800-4,800 rpm.

There's little question that the 5.6-liter V8 in the 2011 Infiniti M56S is a response to the always respectable Mercedes V8. It's comfortably over the 400-hp threshold with 420 hp at 6,000 rpm and 417 lb-ft of torque at 4,400 rpm. But this direct-injected engine has a more explosive power delivery than the Benz delivers.

Partly, this is due to the fact that the throttle map isn't quite sorted out to our liking. Response is unnaturally soft off idle, and then the M56S barrels ahead as if it has been smacked in the rear with a giant mallet.

But you also get the feeling that Infiniti's 5.6-liter wants to flex its muscles for you. There's a more palpable sense of athleticism as the engine revs. This V8 has business to take care of at high rpm and it wants you to feel that.

Now We Get Down to Business
Both Infiniti and Mercedes have settled on seven forward gears for their V8 luxury sedans, and of course, both automatic transmissions drive the rear wheels. Gearing is similar, and with two overdrive gears apiece and fairly tall final-drive ratios for optimal fuel-efficiency, both engines are loafing below 2,000 rpm at a 70-mph cruise.

However, the transmissions behave differently when you start making bigger demands. Here again, the E550 aims for smoothness above all else. Its seven-speed has Comfort, Sport and Manual modes, but this transmission really just wants to be a good automatic. There's no rev-matching on downshifts, but the seven-speed always seems to be in the proper gear without calling attention to itself.

The Infiniti M56S, on the other hand, wants your attention. It has Normal, Sport and Manual modes (plus torque-neutering "Eco" and "Snow" modes), and it serves up zingy, rev-matched downshifts. Leave it in Sport mode and it won't let you down on a mountain road. Those throttle blips are fun going into a turn, and the transmission lands you in the heart of the engine's power band when you're powering away from a corner apex.

Curiously, the M56S's seven-speed is sometimes a bit slow with upshifts (glacially so in Manual mode), and this, along with its funky throttle map, keeps the car from being significantly quicker than the E550.

The Infiniti hits 60 mph from a standstill in 5.2 seconds (4.9 seconds with 1 foot of rollout like on a drag strip) versus 5.3 seconds (or 5.0 seconds with rollout) for the Mercedes. That margin holds through the quarter-mile, with the M56S crossing the line in 13.4 seconds versus the E550's performance of 13.5 seconds. But the M56S's 106.1-mph trap speed, versus 104.8 for the E550, suggests the Infiniti is indeed leaving some performance on the table.

Sport Sedan vs. Luxury Sedan
Don't look for the 2011 Infiniti M56S to pull any punches on back roads, though. It wants to be a sport sedan, and in most respects, it is exactly that. Think about what the BMW 5 Series used to be and you'll have an idea of how it feels.

Setting up for a corner brings visceral joy. It feels like you can just stand on the brakes (upgraded via the Sport package and dealer-installed R-spec brake pads) repeatedly, and they'll still bite hard. In the end the M stopped from 60 mph in 112 feet at our test track and, by the seventh stop, it was still doing it in less than 114 feet. The big 245/40R20 95W Bridgestone Potenza RE050As live up to their reputation for big grip, too.

You sense that grip as you add steering input and you delight in the feedback and the heft in the wheel, and though the M56S's steering feels heavy, it never feels too heavy for the character of the car. The M turns in sharply and with minimal body roll. If you're brave enough to turn off the stability control, you get a little tail-out attitude but nothing too scary.

The M56S slaloms at 66.8 mph, which is faster than a 2009 BMW 550i (64.9 mph), though much slower than the supernatural E63 and CTS-V. It's good for 0.88g on the skid pad, so it's right in line with the 2009 550i.

Alongside the athletic Infiniti M56S, there's the Mercedes-Benz E550, which isn't interested in doing tricks for you.

The E-Class has light, accurate steering, but it doesn't say a whole lot and, really, there's not much to say. Its 245/45R17 99H Continental ContiProContact all-season tires don't have much grip. Understeer is what you notice through corners. The E550 goes through the slalom at only 62.8 mph and manages just 0.81g on the skid pad.

You also notice the brake pedal's long travel, yet consistently linear response, which is the safe strategy for autobahn emergencies in Germany. Said response is also consistently mediocre, though, because the tires are mediocre. The E550's best 60-0 stop is 125 feet.

The Mercedes by Three
For all the M56S's dynamic superiority, it's hard for us to tear into the 2010 Mercedes-Benz E550 for not being much fun. This is a luxury sedan without the theatrics. It's blissfully smooth in every respect, from the way its transmission shifts to the way its suspension absorbs a bump, and it is loaded with both leading-edge technology and old-fashioned conveniences.

Since all of three points separate the E550 from the 2nd-place 2011 Infiniti M56S, there's a compelling case for spending your money on a real sport sedan. In all the ways that the Mercedes feels sterile, the Infiniti feels lively. The M is the sort of car that you look for opportunities to drive by yourself, and that's not something we'd do with an E550.

Personal taste is a big factor in choosing one of these V8 sedans. But don't take too long to make your selection. With tougher fuel economy standards coming, the 2011 Infiniti M56S and 2010 Mercedes-Benz E550 might as well be a Tyrannosaurus Rex and Louis XVI walking arm-in-arm into the sunset. They won't get to keep their tasty V8s forever.

The manufacturers provided Edmunds these vehicles for the purposes of evaluation.

Executive Editor Michael Jordan says:
Maybe I've just lost my taste for German sedans. Now they've all become the same generic sausage, only cut into different lengths. Their differences in character and style seem like the result of battles fought long ago and far, far away. The Mercedes-Benz E550 sums up everything about these cars that has become irrelevant, from the unpleasant roundup of styling themes from the past to the overly processed driving experience. As always, I'm looking for the Real Thing, and this is not it.

So it's no wonder that I'm willing to sign up for the Infiniti M56S. Of these two cars, the Infiniti seems to be the one that really embraces modernity, something you can see in the way it has at last turned the styling themes and ergonomic layout of its cabin into a place that is unique to this car company, an identifiable style that Infiniti has been searching for since the original Q45 was introduced in 1990. The undulating exterior sheet metal isn't quite up to the same standard, but it tries to make a relatively new statement at least.

The M56S also drives much like I'd imagine a Q45 to drive. It has a useful amount of poise on the road, which makes it more alive than the somewhat soggy non-S example that I've also spent time in. It's a little too heavy on its feet, though, and it throws its weight from side to side and feels bogged down in wheels that are just too heavy besides. Even so, this car has a kind of toughness when it comes to fast driving that I like a lot. Like every Nissan, the M56S is dominated by its engine, and I particularly like the way this V8 seems to come on the cam and rip at high rpm, something that makes the engine far more dynamic than the industrial (although powerful) motor under the hood of the E-Class.

The German cars in this category have become downsize clones of their larger, luxury siblings, and the forthcoming 2011 BMW 5 Series shows that even BMW has given in to this influence. The Infiniti M56S tries harder to be right size, much like the BMW 5 Series has been up until now, and that's the kind of car that I want to drive into the future.

You expect to get a long list of amenities and leading-edge technology when you buy a luxury sedan. Both the 2011 Infiniti M56 and 2010 Mercedes-Benz E550 offer lots of techie stuff, but the Mercedes offers a much wider array of equipment, both standard and optional. Although the Infiniti fared better in the performance and pricing categories, the Benz gained back considerable ground in this comparison test just for its sheer amount of stuff.

  2011 Infiniti M56 2010 Mercedes-Benz E550
Adaptive cornering headlights O* O
Adaptive cruise control (all-speed) O* O
Adaptive suspension damping N/A S
Automatic high beams N/A S
Automatic recirculation and air purification O N/A
Blind-spot monitoring system O* O
Driver drowsiness monitoring system N/A S
Folding rear seat N/A O
Knee airbag (driver) N/A S
Navigation system S O
Night-vision system N/A O
Pelvic airbags (driver & front passenger) N/A S
Power trunk lid N/A O
Rearview camera S O
Telematics N/A S

S: Standard
O: Optional
O*: Optional but not equipped on test vehicle
N/A: Not Available

Adaptive cornering headlights: Once you've experienced the sense of mastery that comes with the ability to see around corners in the dark, you'll never again be satisfied with conventional headlights. This feature is optional on both the 2011 Infiniti M56 and the 2010 Mercedes-Benz E550.

Adaptive cruise control (all-speed): It doesn't get much more convenient than being able to set the cruise control and let the car adjust your speed for you when traffic slows down. These all-speed systems (optional on both sedans) will use the brakes to bring you all the way down to a stop when freeway traffic goes solid.

Adaptive suspension damping: One set of damping characteristics just isn't enough anymore, at least not when you're spending this kind of money. The standard adaptive damping system in the E550 lets you prioritize comfort or control, depending on your mood. Adaptive dampers become even more important on sedans with an aggressive wheel/tire package, as you may want to take the edge off when you're just commuting. To not offer these on the M56 seems like a serious miscalculation.

Automatic high beams: Here's another big help on dark roads: You turn on the high beams and when you come up on another car or approach one coming the other way, the car automatically switches to low beams. When you're past that traffic, it switches back to high beams. This feature is optional on the Mercedes.

Automatic recirculation and air purification: In this price range, you'd expect a deluxe climate control system with an auto-recirculate feature, yet only the Infiniti offers this functionality as an option. The M56's so-called Forest Air system "attempts to re-create the refreshing climate and natural breezes of a relaxing forest setting," according to Infiniti. We wouldn't go that far, but we do like the variable vent flow in "Breeze" mode. The system also controls for humidity and uses a grape polyphenol filter and an air purifier to help keep the nasty stuff out.

Blind-spot monitoring system: It can be stressful to keep track of cars on either side of you when you're picking your way through heavy traffic and trying to make sure you're in the correct lane for your exit. Blind-spot monitoring and warning systems (optional on both cars) give you one more set of eyes before you make your move.

Driver drowsiness monitoring system: These sedans are made for long trips, and one of these days, you might start to doze off. The Mercedes monitors your behavior and will give you a jolt before things get out of hand.

Folding rear seat: These are sedans, not coupes, so there should be some practicality built into them. The optional split-folding rear seats in the E550 fold down perfectly flat.

Knee airbag (driver): Lower-leg injuries are common in a major front-end crash. A knee airbag can help minimize the risk for the driver. It's standard in the Benz.

Navigation system: You'd think a deluxe navigation system would be standard fare in these cars, but it's technically possible to buy an E550 without nav.

Night-vision system: Early night-vision systems were fairly crude and something of a gimmick. The optional system in the Mercedes E-Class is the real deal. Clear black-and-white images are projected onto the central screen, and they're a real help on dark streets.

Pelvic airbags (driver & front passenger): Here's the maximum protection argument again in the Mercedes. Yeah, you could probably survive a crash with just torso- and head-protecting airbags, but if you can have lower-body protection as well, you might as well take it all.

Power trunk lid: If crossovers can have a power liftgate, why shouldn't a luxury sedan have a power trunk lid?

Rearview camera: Of course you can have a back-up camera, but Infiniti gives it to you as standard and the display is complete with green, yellow and red marker lines to help you judge distances. Mercedes charges extra for a camera and it doesn't have marker lines.

Telematics: Even if you never use TeleAid's concierge features, you'll be glad to have that one day in a decade when you have a real emergency and help is only a button-push away. Can't do that in the Infiniti.

Final Rankings
  Item Weight 2010 Mercedes-Benz E550 2011 Infiniti M56
Personal Rating 2.5% 66.7 83.3
Recommended Rating 2.5% 66.7 83.3
Evaluation Score 20% 80.0 78.8
Feature Content 20% 75.6 24.4
Performance 25% 84.4 100.0
Fuel Consumption 10% 97.7 100.0
Price 20% 88.3 100.0
Total Score 100.0% 83.0 79.8
Final Ranking   1 2

Personal Rating (2.5%): Purely subjective. After the test, each participating editor ranks the sedans in order of preference based on which he would buy if money were no object.

Recommended Rating (2.5%): After the test, each participating editor ranks the vehicles in order of preference based on which he thinks would be best for the typical midsize luxury sedan buyer.

28-Point Evaluation (20%): Each participating editor scores each vehicle based on a comprehensive 28-point evaluation. The evaluation covers everything from control feel to cupholders. Scoring is calculated on a point system, and the scores listed are averages based on all test participants' evaluations.

Feature Content (20%): Features are a big deal in midsize luxury sedans, and you can expect to find leading-edge technology in both of these cars. We've picked 15 key features in the 2011 Infiniti M56 and 2010 Mercedes-Benz E550. For each sedan, the score is based on the number of actual features it has versus the total possible (15). Standard and optional equipment were taken into consideration.

Performance Testing (25%): Each vehicle is run through Inside Line's regimen of standardized instrumented tests: acceleration (0-60 and quarter-mile), braking (60-0), 600-foot slalom and 200-foot-diameter skid pad. Points are awarded as a percentage of the best overall performance in each test. Note that we've weighted performance a hefty 25 percent, given our feeling that if you're looking at V8-equipped premium sedans, performance is clearly a big factor for you.

Fuel Economy (10%): The scores listed are the result of a simple percentage calculation based on the car with the highest EPA combined fuel economy rating (55 percent city plus 45 percent highway).

Price (20%): The numbers listed are the result of a simple percentage calculation based on the less expensive of the two sedans in this comparison test. Using the "as tested" prices of the actual evaluation vehicles, the lower-priced Infiniti M56 receives a score of 100, with the Mercedes-Benz E550 receiving a proportionally lesser score.

Model year2010
Year Make Model2010 Mercedes-Benz E-Class E550 4dr Sedan (5.5L 8cyl 7A)
Vehicle TypeFour-door, five-passenger midsize sedan
Base MSRP$57,175
Options on test vehicleIndium Grey Metallic Paint ($720); Premium 2 Package ($6,800 -- includes COMAND system with hard drive navigation, voice control, Gracenote media database; HD digital radio, Harman Kardon Logic 7 surround sound system with Dolby Digital 5.1, Sirius, iPod interface, heated/ventilated front seats, rearview camera, adaptive bi-xenon headlights, LED DRLs, Keyless Go and electronic trunk closer); Driver Assistance Package ($2,900 -- includes Distronic Plus all-speed cruise control, PreSafe emergency braking system, Lane Keeping Assist and Blind Spot Assist); Night View Assist Plus ($1,750); Parktronic With Parking Guidance ($950); Drive Dynamic Multicontour Driver Seat With Massage ($650); Wood/Leather Steering Wheel ($580); Split-Folding Rear Seats ($430); Rear Side Airbags (No charge); Burl Walnut Wood Trim (No charge -- includes walnut wood trim on doors, dash and center console).
As-tested MSRP$71,955
Assembly locationSindelfingen, Germany
ConfigurationLongitudinal, front-engine, rear-wheel drive
Engine typeNaturally aspirated port-injected gasoline V8
Displacement (cc/cu-in)5,461cc (333cu-in)
Block/head materialAluminum/aluminum
ValvetrainDouble overhead camshafts, four valves per cylinder, variable intake and exhaust valve timing
Compression ratio (x:1)10.7
Redline, indicated (rpm)6,400
Fuel cutoff/rev limiter (rpm)6,750
Horsepower (hp @ rpm)382 @ 6,000
Torque (lb-ft @ rpm)391 @ 2,800
Fuel typePremium unleaded (required)
Transmission typeSeven-speed automatic with column shifter and steering-wheel-mounted paddles
Transmission ratios (x:1)I = 4.38, II = 2.86, III = 1.92, IV = 1.37, V = 1.00, VI = 0.82, VII = 0.73, R = 3.42 (2.23 comfort mode)
Final-drive ratio (x:1)2.47
Suspension, frontIndependent, MacPherson struts, air springs, adaptive dampers, stabilizer bar
Suspension, rearIndependent, multilink, air springs, adaptive dampers, stabilizer bar
Steering typeSpeed-proportional, hydraulic-assist power rack-and-pinion
Steering ratio (x:1)17.0
Tire make and modelContinental ContiProContact
Tire typeAll-season
Tire size245/45R17 99H (33 cold psi front/42 cold psi rear)
Wheel size17-by-8 inches front and rear
Wheel materialCast aluminum
Brakes, frontCross-drilled, ventilated 13.5-by-1.3-inch disc with four-piston fixed caliper
Brakes, rearVentilated 12.6-by-0.9-inch disc with single-piston sliding caliper
Track Test Results
Acceleration, 0-30 mph (sec.)2.3
0-45 mph (sec.)3.6
0-60 mph (sec.)5.3
0-75 mph (sec.)7.6
1/4-mile (sec. @ mph)13.5 @ 104.9
0-60 with 1 foot of rollout (sec.)5.0
0-30 mph, trac ON (sec.)2.3
0-45 mph, trac ON (sec.)3.6
0-60 mph, trac ON (sec.)5.3
0-75 mph, trac ON (sec.)7.6
1/4-mile, trac ON (sec. @ mph)13.5 @ 104.9
0-60, trac ON with 1 foot of rollout (sec.)5.0
Braking, 30-0 mph (ft.)31
60-0 mph (ft.)125
Slalom, 6 x 100 ft. (mph)62.8
Slalom, 6 x 100 ft. (mph) ESC ON60.2
Skid pad, 200-ft. diameter (lateral g)0.81
Skid pad, 200-ft. diameter (lateral g) ESC ON0.81
Sound level @ idle (dB)41.5
@ Full throttle (dB)72.2
@ 70 mph cruise (dB)64.0
Engine speed @ 70 mph (rpm)1,600
Test Driver Ratings & Comments
Acceleration commentsHard to launch with so much torque and so little tire. Very good low end and likes to rev as well. Upshifts very smoothly. Best run was with the traction control on, but just barely...virtually identical results...good traction control.
Braking commentsBraking rating: Average. Typical M-B belt-cinching freakout with ABS. Consistently noisy tires and ABS cycling. Stops are well grouped but not particularly short. Pedal effort remained low and travel long.
Handling commentsHandling rating: Good. Slalom: Excellent steering feel and weight; however, yaw response is delayed. Best not to overcook entry; rather, slow-in/fast-out works. ESP not fully off but only intrudes when all is lost. Skid pad: Excellent balance on the brink of understeer -- only requires throttle input to alter course. Steering remains light and talkative. Same is true with ESP on, though the throttle closes on its own.
Testing Conditions
Test date3/16/2010
Test locationCalifornia Speedway
Elevation (ft.)1,121
Temperature (°F)81.9
Relative humidity (%)13.6
Barometric pressure (in. Hg)29.00
Wind (mph, direction)4.0 (tailwind)
Odometer (mi.)3,716
Fuel used for test91 octane
As-tested tire pressures, f/r (psi)33 front/42 rear
Fuel Consumption
EPA fuel economy (mpg)16 city/24 highway/18 combined
Edmunds observed (mpg)21.3 best/18.9 worst/19.7 average (over 873 miles)
Fuel tank capacity (U.S. gal.)21.1
Driving range (mi.)337.6 city/506.4 highway/379.8 combined (EPA-estimated)
Audio and Advanced Technology
Stereo descriptionOptional Harman Kardon Logic 7 5.1 surround-sound audio system with 14 speakers, 450 watts and six-disc CD/DVD in-dash changer (equipped)
iPod/digital media compatibilityOptional iPod via propietary cable (equipped), standard PC card reader
Satellite radioOptional, Sirius (equipped)
Hard-drive music storage capacity (Gb)Optional, 6GB capacity (equipped)
Rear seat video and entertainmentOptional, twin 8-inch LCD screens in front headrests, auxiliary inputs, wireless headphones, remote control (not equipped on test vehicle)
Bluetooth phone connectivityStandard
Navigation systemOptional, hard drive-based, with traffic (equipped)
Telematics (OnStar, etc.)Standard, TeleAid
Smart entry/StartOptional (equipped)
Parking aidsOptional parking sonar front and rear, optional back-up camera (equipped)
Blind-spot detectionOptional (equipped)
Adaptive cruise controlOptional, all-speed (equipped)
Lane-departure monitoringOptional (equipped)
Collision warning/avoidanceOptional (equipped)
Night VisionOptional (equipped)
Driver coaching displayNot available
Dimensions & Capacities
Curb weight, mfr. claim (lbs.)4,034
Curb weight, as tested (lbs.)4,135
Weight distribution, as tested, f/r (%)51.2/48.8
Length (in.)191.7
Width (in.)75.9
Height (in.)57.7
Wheelbase (in.)113.1
Track, front (in.)62.2
Track, rear (in.)62.5
Turning circle (ft.)36.2
Legroom, front (in.)41.3
Legroom, rear (in.)35.8
Headroom, front (in.)37.9
Headroom, rear (in.)38.2
Shoulder room, front (in.)57.8
Shoulder room, rear (in.)56.9
Seating capacity5
Trunk volume (cu-ft)15.9
Tow capacity, mfr. claim (lbs.)1,654
Bumper-to-bumper4 years/50,000 miles
Powertrain4 years/50,000 miles
Corrosion4 years/50,000 miles
Roadside assistanceUnlimited years and mileage
Free scheduled maintenanceFirst 3,000 miles
Model year2011
Year Make Model2011 Infiniti M56S 4dr Sedan (5.6L 8cyl 7A)
Vehicle TypeRear-wheel drive, five-passenger sedan
Base MSRP$58,415
Options on test vehicleMalbec Black, Sport Package R01 ($3,650 -- includes 20-by-9-inch, split five-spoke aluminum-alloy wheels with 245/40R20W-rated summer performance tires; sport-tuned suspension with upgraded springs and double-piston shock absorbers; sport brakes with aluminum four-piston opposed front calipers/two-piston opposed rear calipers; four-wheel active steer; solid magnesium paddle shifters; sport seat with enhanced bolstering; aluminum pedal accents; premium stitched meter hood; sport steering wheel and shift knob; unique front fascia; dark front grille and headlamp housing); Sport Touring Package K02 ($2,000 -- includes Bose studio surround-sound system with digital 5.1-channel decoding, 16 speakers; Forest Air system with advanced auto recirculation, Breeze mode, Plasmacluster air purifier, and Grape polyphenol filter; power rear sunshade); R-Spec High-Friction Brake Pads V92 ($370).
As-tested MSRP$64,435
Assembly locationTochigi, Japan
North American parts content (%)Being Researched
ConfigurationLongitudinal, front-engine, rear-wheel drive
Engine typeNaturally aspirated direct-injected gasoline V8
Displacement (cc/cu-in)5,552cc (339cu-in)
Block/head materialAluminum/aluminum
ValvetrainDOHC, four valves per cylinder, variable intake + exhaust-valve timing and lift
Compression ratio (x:1)11.5
Redline, indicated (rpm)6,700
Fuel cutoff/rev limiter (rpm)6,750
Horsepower (hp @ rpm)420 @ 6,000
Torque (lb-ft @ rpm)417 @ 4,400
Fuel typePremium unleaded (required)
Transmission typeSeven-speed automatic with console shifter and column-mounted paddles with sport/competition modes
Transmission ratios (x:1)1st = 4.783, 2nd = 3.103, 3rd = 1.984, 4th = 1.371, 5th = 1.000, 6th = 0.871, 7th = 0.776
Final-drive ratio (x:1)2.611
Suspension, frontIndependent double wishbones, coil springs, monotube dampers, stabilizer bar
Suspension, rearIndependent multilink, coil springs, monotube dampers, stabilizer bar
Steering typeHydraulic-assist, speed-proportional rack-and-pinion power steering with active rear steer
Steering ratio (x:1)16.9
Tire make and modelBridgestone Potenza RE050A
Tire typeAsymmetrical summer, high-performance (33 psi cold front; 33 psi cold rear)
Tire size245/40R20 95W
Wheel size20-by-9 inches
Wheel materialCast aluminum
Brakes, front14.0-inch one-piece ventilated steel discs with four-piston fixed calipers
Brakes, rear13.8-inch one-piece ventilated steel discs with two-piston fixed calipers
Track Test Results
Acceleration, 0-30 mph (sec.)2.3
0-45 mph (sec.)3.6
0-60 mph (sec.)5.2
0-75 mph (sec.)7.4
1/4-mile (sec. @ mph)13.4 @ 106.1
0-60 with 1 foot of rollout (sec.)4.9
Braking, 30-0 mph (ft.)27
60-0 mph (ft.)112
Slalom, 6 x 100 ft. (mph)66.8
Slalom, 6 x 100 ft. (mph) ESC ON62.8
Skid pad, 200-ft. diameter (lateral g)0.88
Skid pad, 200-ft. diameter (lateral g) ESC ON0.84
Sound level @ idle (dB)41.8
@ Full throttle (dB)74.5
@ 70 mph cruise (dB)66.0
Engine speed @ 70 mph (rpm)1,800
Test Driver Ratings & Comments
Acceleration commentsThe M56 doesn't respond to or allow pedal overlap for a crisp launch so it feels like it stumbles off the line initially, then blammo. Once it starts rolling, however, the engine revs freely up to redline. Upshifts are a little lazy (even in Sport), but rather smooth and inconsistent with regard to shift rpm. Manual shifting proved futile due to time lag between shift request and actual shift.
Braking commentsRating: Very Good -- Medium/firm pedal with very good effectiveness and fade resistance. As the number of runs accumulated, the jump-in characteristics grew more abrupt.
Handling commentsRating: Very Good -- Skid pad: This test punishes the front tires, but they don't lose much grip despite it. Steering weight is pretty hefty, but not what I'd call too heavy. With VDC off, the M56 hits a brick wall of understeer and no amount of throttle manipulation can drive around it. With VDC on, both the throttle and brakes intervene to limit the vehicle speed/heading, but this state requires more steering input to maintain a precise line. Slalom: Feels and looks enormous threading between the cones from behind the wheel, but once I learned to trust the car's ability to oversteer slightly it became clear the limits are higher than initially thought. The M56S dodges cones by rotating about the front wheels -- very good balance that was not apparent on the skid pad. Steering is very responsive and there's plenty of front-end bite to enhance the yaw reaction. With VDC on, however, the car refuses to cooperate with an aggressive driving style and is massively restrained.
Testing Conditions
Test date3/16/2010
Test locationCalifornia Speedway
Elevation (ft.)1,121
Temperature (°F)84.6
Relative humidity (%)14.4
Barometric pressure (in. Hg)28.99
Wind (mph, direction)2.4 tail-/crosswind
Odometer (mi.)3,638
Fuel used for test91-octane
As-tested tire pressures, f/r (psi)33/33
Fuel Consumption
EPA fuel economy (mpg)16 city/25 highway/21 combined
Edmunds observed (mpg)13 worst/21 best/16 average (over 560 miles)
Fuel tank capacity (U.S. gal.)20.0
Driving range (mi.)500
Edmunds estimated monthly fuel cost ($)Being Researched
Audio and Advanced Technology
Stereo descriptionBose Studio Surround with 5.1-channel decoding, 16 speakers
iPod/digital media compatibilityStandard iPod via USB jack
Satellite radioStandard XM
Hard-drive music storage capacity (Gb)Standard 9.3GB music storage capacity
Rear seat video and entertainmentNot available
Bluetooth phone connectivityStandard (includes music streaming)
Navigation systemStandard Hard Drive with XM traffic 8.0-inch WGVA touchscreen display
Telematics (OnStar, etc.)Not available
Smart entry/StartStandard ignition/doors
Parking aidsStandard back-up camera
Blind-spot detectionOptional
Adaptive cruise controlOptional
Lane-departure monitoringOptional
Collision warning/avoidanceOptional
Night VisionNot available
Driver coaching displayStandard throttle-pedal feedback in "Eco" mode, current/average mpg display
Dimensions & Capacities
Curb weight, mfr. claim (lbs.)4,028
Curb weight, as tested (lbs.)4,084
Weight distribution, as tested, f/r (%)55/45
Length (in.)194.7
Width (in.)71.1
Height (in.)59.1
Wheelbase (in.)114.2
Track, front (in.)62.0
Track, rear (in.)61.8
Turning circle (ft.)36.7
Legroom, front (in.)44.4
Legroom, rear (in.)36.2
Headroom, front (in.)39.1
Headroom, rear (in.)37.7
Shoulder room, front (in.)58.4
Shoulder room, rear (in.)56.7
Seating capacity5
Trunk volume (cu-ft)14.9
GVWR (lbs.)4,938
Ground clearance (in.)5.9
Bumper-to-bumper4 years/60,000 miles
Powertrain6 years/70,000 miles
Corrosion7 years/Unlimited miles
Roadside assistance4 years/60,000 miles
Free scheduled maintenanceNot available
Leave a Comment