Road Test
Follow-Up Test: 2007 Mercedes-Benz E320 Bluetec
The not-so diesel
Diesel is no longer a dirty word.
Sure, the word alone still conjures up visions of smoke bellowing from a tailpipe, an engine chattering like Eskimo teeth and a blackened rear bumper. But with the introduction of its 2007 Mercedes-Benz E320 Bluetec, Americans will no longer think dirty when they think diesel. The days of squinting eyes, pinching nostrils and the inevitable headache are over.
Not so stinky
The main ingredients to clean emissions for the '07 Bluetec are a combination of specialized catalysts and a particulate filter in the exhaust system. Although its name is derived from a system called AdBlue, which further cleans the car's emissions, the system won't be part of the package until the 2009 model year. Until then the E320 is only up to EPA diesel emission standards for 45 states. That makes the eco-stingy states of California, Maine, Massachusetts, New York and Vermont off-limits.
Fifty-state-compliant Bluetecs will not be limited to E-Class models for '09, but also available as GL-, ML- and R-Classes. For each model, the AdBlue (a.k.a. urea) system works identically. Urea from a storage reservoir is injected into exhaust gases prior to their reaching the catalytic converter. Heat from the gases cause a reaction with the urea, creating ammonia. Within the catalytic converter this ammonia diffuses the noxious nitrous oxides (exhaust gas) and turns them into enviro-friendly byproducts, nitrogen and water. Mercedes says that AdBlue reservoir refills will take place during regularly schedule service.
Ultralow-sulfur diesel (ULSD) is another component in the low-emission equation. ULSD is clean-burning and as EPA restrictions increase, more and more will be available at U.S. fuel pumps. Current mandates require it at 80 percent of U.S. retail locations. Pumps at the locations we visited wore clearly marked stickers designating the diesel as 15-ppm emissions-friendly. During our time with the car, only one of the six stations we visited did not carry the proper grade of fuel. Surprisingly enough it was located in Fontana, California, a mini-mecca of diesel trucks.
Not so noisy
Climbing into the driver seat of the E320 Bluetec is just the same as climbing aboard an E550, which is to say sublime. Although thoroughly modern, the ambience is more old-world than high-tech, the experience always warm and inviting. The E320 receives the same minor interior and exterior cosmetic upgrades as other '07 E-Class sedans. These include new front and rear bumper designs, a more laidback grille, more heavily splayed headlamps and a shifter and steering wheel lifted from the interior of the SL550 roadster.
With the windows down at idle there is a faint clack-clack-clack from its aluminum-block 3.0-liter diesel V6, but with the sedan's windows up its occupants are none the wiser. Not as much can be said for the 3.2-liter diesel from the E320 CDI it replaces. In fact, the Bluetec is quieter than the sedate-at-idle E550 we tested only a few months ago.
At the test track we were surprised with the Bluetec's performance. Despite the ESP system kicking in before we reached the limits of its small 16-inch Michelin Energy tires, the car generated 0.81g on the skid pad, matching the performance of the equally computer-limited E550. Its 62.6-mph slalom speed is also respectable, although it, too, was limited by the stability control system.
Because of its small wheels, the E320 also receives the smallest brakes of all E-Class sedans. Their petite stature still offers enough surface area to stop the car in 129 feet from 60 mph, not too shabby considering the car's 3,985-pound as-tested weight. Highway and around-town ride are also not adversely affected by the special tires; the E320 drives as luxuriously as any other E-Class.
Slow acceleration times were always a diesel gripe, but those days are gone. During acceleration testing there was only brief turbo lag before the Bluetec burst to life, clocking a 0-60-mph time of 6.8 seconds and crossing the quarter-mile marker in 15.2 seconds at 91.1 mph with the engine still pulling strong.
According to Mercedes, the E350 is only one-tenth quicker to 60 mph than its Bluetec counterpart even though the gasoline burner has 60 more horsepower. Of course, we failed to mention that the diesel has 388 pound-feet of giggle-inducing torque. That's 130 more than the E350 and only three less than the E550. With its narrow power band, the seamless seven-speed transmission shifts often and the torque is not there forever, but it's pretty remarkable when it is.
Not so expensive
Smooth power delivery made 35 mpg easily attainable during highway cruises, although the EPA-estimated 37 mpg remained just out of our reach. Combined with occasionally spirited city driving, our total observed fuel economy was less impressive, 24.4 mpg. This still trumps the estimated 19 city/26 highway of the E350, and with an MSRP only $1,000 higher, the $51,550 Bluetec really seems to be the better choice.
Each time we fueled the Bluetec we noted the price of gasoline. We recorded the average cost of 91-octane premium at $2.60/gallon and 87-octane regular at $2.49/gallon. When averaging the cost of ULSD at each fill-up, we paid an eye-opening $3.19/gallon.
At first glance it appears the diesel is at a disadvantage, but it actually comes out on top. EPA highway estimates for their shared 20-gallon fuel tanks project a range of 520 miles per tank in the E350 and an incredible 740 in the E320. Using our observed fuel prices, it costs the Bluetec driver roughly $64 while the E350 driver needs about $74 to travel the same 740 miles. Even running 87 octane at that rate has the diesel about $7 ahead. That adds up quickly over a few years of ownership.
Mercedes is leading the automotive world into a new era with its ultralow-sulfur-burning E320 Bluetec. Until the competition can catch up, they will have to find solace in knowing that at least they're not stuck behind another smoky "that guy" diesel.
The manufacturer provided Edmunds this vehicle for the purposes of evaluation.
Sure, the word alone still conjures up visions of smoke bellowing from a tailpipe, an engine chattering like Eskimo teeth and a blackened rear bumper. But with the introduction of its 2007 Mercedes-Benz E320 Bluetec, Americans will no longer think dirty when they think diesel. The days of squinting eyes, pinching nostrils and the inevitable headache are over.
Not so stinky
The main ingredients to clean emissions for the '07 Bluetec are a combination of specialized catalysts and a particulate filter in the exhaust system. Although its name is derived from a system called AdBlue, which further cleans the car's emissions, the system won't be part of the package until the 2009 model year. Until then the E320 is only up to EPA diesel emission standards for 45 states. That makes the eco-stingy states of California, Maine, Massachusetts, New York and Vermont off-limits.
Fifty-state-compliant Bluetecs will not be limited to E-Class models for '09, but also available as GL-, ML- and R-Classes. For each model, the AdBlue (a.k.a. urea) system works identically. Urea from a storage reservoir is injected into exhaust gases prior to their reaching the catalytic converter. Heat from the gases cause a reaction with the urea, creating ammonia. Within the catalytic converter this ammonia diffuses the noxious nitrous oxides (exhaust gas) and turns them into enviro-friendly byproducts, nitrogen and water. Mercedes says that AdBlue reservoir refills will take place during regularly schedule service.
Ultralow-sulfur diesel (ULSD) is another component in the low-emission equation. ULSD is clean-burning and as EPA restrictions increase, more and more will be available at U.S. fuel pumps. Current mandates require it at 80 percent of U.S. retail locations. Pumps at the locations we visited wore clearly marked stickers designating the diesel as 15-ppm emissions-friendly. During our time with the car, only one of the six stations we visited did not carry the proper grade of fuel. Surprisingly enough it was located in Fontana, California, a mini-mecca of diesel trucks.
Not so noisy
Climbing into the driver seat of the E320 Bluetec is just the same as climbing aboard an E550, which is to say sublime. Although thoroughly modern, the ambience is more old-world than high-tech, the experience always warm and inviting. The E320 receives the same minor interior and exterior cosmetic upgrades as other '07 E-Class sedans. These include new front and rear bumper designs, a more laidback grille, more heavily splayed headlamps and a shifter and steering wheel lifted from the interior of the SL550 roadster.
With the windows down at idle there is a faint clack-clack-clack from its aluminum-block 3.0-liter diesel V6, but with the sedan's windows up its occupants are none the wiser. Not as much can be said for the 3.2-liter diesel from the E320 CDI it replaces. In fact, the Bluetec is quieter than the sedate-at-idle E550 we tested only a few months ago.
At the test track we were surprised with the Bluetec's performance. Despite the ESP system kicking in before we reached the limits of its small 16-inch Michelin Energy tires, the car generated 0.81g on the skid pad, matching the performance of the equally computer-limited E550. Its 62.6-mph slalom speed is also respectable, although it, too, was limited by the stability control system.
Because of its small wheels, the E320 also receives the smallest brakes of all E-Class sedans. Their petite stature still offers enough surface area to stop the car in 129 feet from 60 mph, not too shabby considering the car's 3,985-pound as-tested weight. Highway and around-town ride are also not adversely affected by the special tires; the E320 drives as luxuriously as any other E-Class.
Slow acceleration times were always a diesel gripe, but those days are gone. During acceleration testing there was only brief turbo lag before the Bluetec burst to life, clocking a 0-60-mph time of 6.8 seconds and crossing the quarter-mile marker in 15.2 seconds at 91.1 mph with the engine still pulling strong.
According to Mercedes, the E350 is only one-tenth quicker to 60 mph than its Bluetec counterpart even though the gasoline burner has 60 more horsepower. Of course, we failed to mention that the diesel has 388 pound-feet of giggle-inducing torque. That's 130 more than the E350 and only three less than the E550. With its narrow power band, the seamless seven-speed transmission shifts often and the torque is not there forever, but it's pretty remarkable when it is.
Not so expensive
Smooth power delivery made 35 mpg easily attainable during highway cruises, although the EPA-estimated 37 mpg remained just out of our reach. Combined with occasionally spirited city driving, our total observed fuel economy was less impressive, 24.4 mpg. This still trumps the estimated 19 city/26 highway of the E350, and with an MSRP only $1,000 higher, the $51,550 Bluetec really seems to be the better choice.
Each time we fueled the Bluetec we noted the price of gasoline. We recorded the average cost of 91-octane premium at $2.60/gallon and 87-octane regular at $2.49/gallon. When averaging the cost of ULSD at each fill-up, we paid an eye-opening $3.19/gallon.
At first glance it appears the diesel is at a disadvantage, but it actually comes out on top. EPA highway estimates for their shared 20-gallon fuel tanks project a range of 520 miles per tank in the E350 and an incredible 740 in the E320. Using our observed fuel prices, it costs the Bluetec driver roughly $64 while the E350 driver needs about $74 to travel the same 740 miles. Even running 87 octane at that rate has the diesel about $7 ahead. That adds up quickly over a few years of ownership.
Mercedes is leading the automotive world into a new era with its ultralow-sulfur-burning E320 Bluetec. Until the competition can catch up, they will have to find solace in knowing that at least they're not stuck behind another smoky "that guy" diesel.
The manufacturer provided Edmunds this vehicle for the purposes of evaluation.
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