It wasn't long ago that the majority of car buyers snubbed diesel-engine-equipped luxury cars. Not that we blame them. After all, who wants to shell out the big bucks for a righteous car that glides down the road as smooth as a hovercraft, has an interior that coddles and caresses, but has an engine that sounds like you're shaking a tin can full of rocks and smokes like someone is burning a tire in the trunk?
Fortunately, those days are long gone. As we all know, the modern diesel engine is a high-tech masterpiece that is enjoying a runaway resurgence in the mainstream. Due to some impressive engineering ingenuity, it has lost its high-decibel racket, as well as its notorious exhaust smoke. Finally, Rudolf's invention is once again finding its way into luxury cars, and we say it's about time.
We recently spent some quality time with the '06 Mercedes-Benz E320 CDI. To call this vehicle polished would be like saying that Mount Everest is a cute little hill. During our initial inspection, we were impressed by the impeccable fit and finish of the car, as well as the attention to small, but welcome, items (like covered trunk hinges) that make the trunk area flow visually when the trunk lid is open. As we slid into the creamy leather driver's seat, the door closed with little effort like the door latch was tenderly reaching out to grasp the catch. We feasted our eyes on Burl Walnut trim, and the Stone interior color made the car feel open, airy, and inviting. There is no shortage of technology in the E320 either. There are easy-to-understand, yet elegant dual-zone electronic climate controls, a nine-speaker Harmon/Kardon audio system with LOGIC7 surround sound, and a DVD navigation system. It would take 20 more pages to detail the scores (literally) of other high-tech devices that loom inside the E320, but we want to talk about the engine.
There are a lot of bells and whistles in the E320, but they're integrated into the design
At highway speed, the CDI engine is imperceptible from an audio perspective. It's just the
Our tester came shod with 225/55R16 all-season tires mounted on 16-inch dual-spoke light a
The E320 is powered by a turbocharged and intercooled 3.2L 24-valve inline six-cylinder diesel engine. This powerhouse features a cast-iron block, aluminum head, common-rail direct injection (that delivers fuel at a pressure of 23,200 psi), dual overhead camshafts, and Bosch CDI electronic injection with pilot injection. Four hundred revolutions shy of its 4,600-rpm max engine speed, it makes 201 hp. The E320 produces a blistering 369 lb-ft of torque at only 1,800 rpm. The engine is mated to a five-speed automatic transmission that boasts Touch Shift and driver-adaptive shift logic. The engine lopes along at 1,600 rpm at 55 mph and 2,300 rpm at 75 mph.
Driving the E320 CDI is a lesson in refinement. It's clear that Mercedes engineers spent a considerable amount of time ensuring that the 3.2L CDI engine integrates seamlessly with the dignified E320. Diesel rattle is muted-more like nonexistent-throughout the engine's rpm range. When it comes to power, the engine hauls the 3,835-pound sedan with authority. There is no perceptible turbo lag, and during hard acceleration the engine generates the sound and pull of a small-block V-8. No kidding. As a matter of fact, Mercedes says that the E320 sprints from 0-60 in 6.6 seconds, which is only one-tenth of a second behind the gasoline V-6-powered E350. Then there's the E320's mileage. Hold onto your cognac, because the E320 is rated at a darn respectable 27 mpg city and a whopping 37 mpg highway. This translates to a Docker-creasing cruising range of about 777 miles, thanks to the E320's 21-gallon fuel tank. Our test tank of fuel returned 26.9 mpg. We think this is pretty darn good considering that this figure represents mostly city driving and our notoriously heavy right foot.
By the time you read this, Mercedes will be poised to unveil the new '07 E320 CDI that is powered by a new BLUETEC diesel V-6 (see sidebar). Now might be a great time to beat feet over to your Mercedes dealer and see if you can score a deal on a '06 before they're all gone.
Model: '06 Mercedes-Benz E320 CDI
Base price: $51,050
Price as tested: $55,465
Options as tested: Pewter paint ($690), Premium Package ($2,950),destination and delivery ($775)
Type: 3.2L turbocharged inline 24-valve six-cylinder diesel
Displacement liter/ci): 3.2/196.6Mfg.'s hp @ rpm: 201 @ 4,200
Mfg.'s torque (lb.-ft.) @ rpm: 369 @ 1,800-2,600
Transmission: Five-speed automatic
Final drive: 2.65:1
Front: Coil spring, double wishbone, gas shocks, stabilizer bar
Rear: Coil spring, five-link, gas shocks, stabilizer bar
Type: Power-assisted rack-and-pinion
Turns (lock-to-lock): 2.8
Turning radius (ft.): 37.4
Front: 12.3-inch vented discs, single-piston calipers, four-channel ABS
Rear: 11.8-inch discs, single-piston calipers, four-channel ABS
Wheels: 16x8 dual-spoke light alloy
Tires: 225/55R16 all season
Base curb weight (lbs.): 3,835
Wheelbase (in.): 12.4
Overall length (in.): 189.7
Overall width (in.): 71.3
Height (in.): 57.0
Track f/r (in.): 61.4/61.2
Cabin volume (cu. ft.): 97.2
Trunk volume (cu. ft.): 15.9
Ground clearance (in.): 4.88
Top speed (mph): 130
Fuel capacity (gal.): 21.1
Fuel mileage (mpg, observed): 26.9
Seating, persons: 5
The outstanding 3.2L diesel engine is designed to be quiet and powerful. It's nestled in a
Mercedes engineers didn't forget that most people drive at night. When either of the front
Even the rear-seat passengers get coddled in luxury. They get top-quality leather seating
COMING SOON: The World'sCleanest Diesel Engine
Beginning in 2007, Mercedes-Benz will fit the E320 with a new 3.0L BLUETEC V-6 turbodiesel engine. This new diesel will generate 210 hp and 388 lb-ft of torque, which is an improvement over the current 3.2L inline six-cylinder diesel. Improved power isn't the whole story, however. Mercedes says that the new BLUETEC engine will be the world's cleanest diesel. The new BLUETEC system depends on the use of ultra low-sulfur diesel fuel, and it incorporates four after-treatment units in the exhaust stream. Those elements include an oxidizing catalytic converter, a particulate filter, an advance "denox" storage converter, and a selective catalytic reduction (SCR) catalytic converter. Further, the new BLUETEC engine can be equipped with AdBlue injection, which is a water-based urea solution that is carried in its own small tank and metered into the exhaust. When this solution is injected into pre-cleaned exhaust gas, ammonia is released, converting nitrogen oxides into harmless nitrogen and water in the SCR catalytic converter. What this all boils down to is a diesel that can meet even the most stringent emissions standards. This could also translate to even more mainstream acceptance of diesel engines. Naturally, we'll have a road test of this new engine in an upcoming issue.