Forgive my ignorance but I have not had a chance to drive a newer generation diesel vehicle from any brand yet. To put my diesel experience in perspective the last diesel car I sat in was my father's 1981 (or '82) VW Jetta and I was 8 years old. Back then diesel cars vomited black smoke upon starting them up and when accelerating onto the highway you could easily finish a few chapters of a novel before reaching your cruising speed. I understand that things have changed a lot since then and diesels a virtually smokeless and quite powerful. Granted diesel engines have tons of torque which translates to power deep down on the rev range but what about power once you are up to speed ? Is passing other vehicles a non-issue or does it require planning and some praying to get up to speed ? For instance does going from 50mph up to 80mph or merging onto the highway require one to "put the pedal to the metal" to keep up with the normal flow of traffic (like in the olden days) or is it like in a gas powered car ? Thanks and I swear I'll try to make some time to drive a diesel ML if not this year then definitely next.

 

Hello LaicepsYdobon:

I have a gas version, and the ML350 run the same 0-60 time of 7.3. From being on the forums for a couple weeks, it seems that the Bluetec owners are very happy and have yet to complain much about the speed.

I have the gas version and I am usually driving in the slow lane (have yet to pass someone). However, I did see on a website site that the gas version is faster in the 1/4 mile. However, these are luxury SUVs and not race cars I think we are more concerned with having power to go up a dirt hill.

 

Read caf's post here: https://mbworld.org/forums/new-m-cla...rivetrain.html. Acceleration is smooth, quiet and effortless.

 

Exactly what I was looking for. Thanks Greg !

 

I just drove a 2012 E 350 Bluetec for 2 days. The engine is the most amazing thing I have ever experienced. Quiet, smooth, and powerfull as can be, really hard to even know it was diesel. I cannot tell you what 400 ft. lbs. of torque feels like. I got 37 mpg and the car had less than 75 total miles on it, I would bet it will get 40 mpg highway once broken in.
At least double that of the gas motor. All this from a 4700 pound sedan. I wish MB would put that 3.5 Bluetec in more MB models.

 

Thanks for the info. I saw a segment on "The Car Show" about the diesel E-Class and the guys were very impressed with it. Dan even said that every E-Class should be sold as a diesel by default. Basically they tried to go across California with one tank of gas (about 800 miles). You can check out the episode here: http://www.hulu.com/watch/298646/the...hats-efficient

 

I agree with everything Caf says in his excellent review. The powertrain is a perfect match between components. I just hit 4,000 miles on my ML and combined city/highway is 27 MPG based on fill up last night. This truck is no slug and I sometimes forget that I am driving a diesel. On the highway, the ML seems to "settle in" at 80 MPH (which may get me into trouble one day). Rapid acceleration from let's say 40 MPH tio 70 MPH is no problem at all - although I have to watch the tachometer as I am still breaking in the engine and stay under 3,000 most of the time.

This MB is nothing like my others! I still have nightmares about merging on to the interstate with my 240D!!!

 

I have experience with two diesel powered vehicles...both recent models.In short all I can say about both of them is *amazing*.Unlike earlier diesels they're quick,quiet and clean.I'm now a true believer...I'll never again drive anything but a diesel.

 

Here are Autoweek's comments on the diesel in the S-class. Most comments should hold for the ML, except the slightly hier weight will reduce performance a small amount.

EDITOR WES RAYNAL: I love this 2012 Mercedes-Benz S350 Bluetec. The S-class is my favorite of the big German luxury cars, followed closely by the Audi A8, the BMW 7-series in third and the Lexus LS bringing up the rear.

I like the S because it offers, to me, the best overall combination of looks, quality and smoothness. Adding this nifty little six-cylinder diesel enhances the package.

The engine might want a little for horsepower, but not torque--there's plenty of that, more than enough to haul this baby around town and down the freeway. Except, under heavy acceleration, there was nothing to indicate that I was driving a diesel, all quiet and smooth--really smooth. And returning mid-20s mpg on the way home and back to work, plus noodling around town last night, is awesome. Refined is the word I keep thinking of.

Every time we write about one of the big gas-powered German luxury cars online, the comments section below the story is filled with “why don't they offer a diesel? Where's the diesel? Bring on the diesel!” Well, folks, here it is. Line up and get 'em--no more excuses.


EXECUTIVE EDITOR ROGER HART: One drive in this car and it could convince even the most avid diesel haters to change their tune. Man, this thing is smooth, and quiet, and yes, fuel-efficient. As the astute Mr. Raynal observed, this is the pinnacle of the German luxo cars. The 450 lb-ft of torque is sweet to have underfoot, and the 24 mpg is not bad, either. Cruising at 80 mph on the freeway there is no hint of engine noise. And you get all of the beautiful, comfortable, and, yes, luxurious interior of the S-class.

As for diesels in the United States, this car is Exhibit A of a perfect application and execution.


EXECUTIVE EDITOR BOB GRITZINGER: I echo Raynal and Hart on this 2012 Mercedes-Benz S350 Bluetec diesel--what a winner. Having just spent part of a day driving the similarly diesel-powered ML350 Bluetec SUV earlier in the week, I was surprised at how much stronger the engine felt in the full-size sedan. The S-class checks in at some 400 pounds lighter than the M-class, and the weight savings makes a huge difference. I found the S350 Bluetec strong not only off the line, but also in that key 50- to 80-mph range, where a lot of highway driving takes place. Punching up power at speed in the S350 diesel was promptly rewarded with instant response and action. The thing flies, and seemingly without effort.

Driving this made me think back to the old days of Mercedes diesels in the States, back when few oil-burners existed on American highways outside of the truck stop. A friend's dad drove a late '60s Benz that was quite a special sedan, but one fraught with weaknesses when it came to reliable operation. You had to switch on the ignition and wait for the glow plugs to heat up, and then hope there was enough battery left to the crank the engine to life. That's when the sooty diesel exhaust started spewing, which was OK as long as you were inside the car, but it was choking if you were standing outside. The engine clattered about its business, which was audible in or out of the car, and it didn't seem to offer much in terms of power.

Thankfully, with this S350 Bluetec, that classic from the past is now fully planted in the 21st century for everyone with enough money to enjoy. If you want your S-class and fuel economy, too, or you just yearn for a fine Mercedes diesel sedan, this is your car.

 

At 75 mph, where is the rpm in the diesel?

Bad thing about the gas - going at high speeds I only average about 22 mpg - For me highway at 40 - 55 is good. Over 70 the rpms are too high to get over 22-23 mpg.

 

Not sure about the RPMs! Wait!! Another excuse to go for a ride! Stay tuned!

 

At about 70mph mine is about 1,900RPM.

 

At that speed, aerodynamics are most likely playing a bigger role than RPM with the 7 speed's fairly tall overdrive, even in the gasser.

 

The one I test drove before buying my gasser was nice, it just felt heavier and maybe a little too much for the stock suspension set up. Throttle response was better on the gasser, but you could feel the torque on the diesel despite the extra 300 pounds. I did not want to spend the extra bucks on the upgraded suspension bits. The other thing that pushed me over the edge was the fact that diesel is 50 cents more per gallon than premium where I live, uhgggg! If it was closer to the premium price, then I may have picked one up anyway, despite the different handling feel just to say I finally own a modern diesel.

 

These are the aerodynamic features highlighted (ML 250 BT figures):

Air flow optimisation: the most aerodynamically efficient SUV in its class
With a drag coefficient, or Cd value, of 0.32, the new M-Class (ML 250 BlueTEC) also sets a new best figure for this vehicle class (total aerodynamic drag Cd x A = 0.92 m2; predecessor 0.94 m2). Intensive simulations undertaken with the digital prototype, along with final touches added in the wind tunnel, ensure a perfect flow of air around the vehicle. The key factor determining the low wind resistance is the aerodynamic efficiency of the basic body shell, including the optimised design of the front bumper with its integrated spoiler, of the A-pillars and of the roof spoiler, plus numerous other detailed improvements. These include:

■ Sealing around the radiator section with adjustable fan shutter

■ Sealed joints between the bonnet and the headlamps

■ Front wheel spoilers

■ Air outlets in the front wheel well liners

■ Redesigned exterior mirror housings

■ Optimised roof spoiler

■ Side spoilers on the rear window (ML 250 BlueTEC 4MATIC)

■ Underfloor and engine compartment panelling

■ Aerodynamically optimised light-alloy wheels

 

I'm still on the fence between gas and diesel. I think it would amortize over 5 years or so for me, and the extra range is appealing. I'll probably go back and forth until the last minute!

 

Thanks for the detailed info. That's a lot of aero optimization . The truck is one of the quietest vehicles I have owned at speed so you can tell a lot of effort went in the wind tunnel testing.

 

Even though the Diesel is 300 lbs more, once the vehicle is moving its not that big of a concern. However, it would make sense that the TQ the Diesel has helps at higher speeds because of the opposing forces of the aerodynamics - this equals to the diesel working less than the gasser against these forces. Even though we have the same aerodynamics, this would also be way the gasser works less to go up a hill. Our gassers need more higher rpms to transport the weight.

 

I don't think so. With the 1,500 upfront cost - and the added price of diesel and the need to included "AdBlue" not sure if that would happen ever really.

Try not to look at it as a cost savings option - instead a option that adds torque and the ability to go a longer range.

 

I was thinking the same thing. The attention to aerodynamics yields dividends not only in fuel economy, but also in reducing noise at speed. I also think it makes it easier to wash, for those of us who hand wash.

I do think they went a little overboard on the sideview mirrors, though. I know that small mirrors help with reducing aero drag, but the tradeoff is reduced utility of the mirrors.

 

They are small, but I'm not sure they are any smaller than those on the W164.

 

What is the average "real-life" mpg over the life of the fuel tank for the Bluetec - I am playing with some numbers.

 

My real life MPG for combined driving is 27

 

Many of the car rags reported 23-24 mpg for the diesel and 19-20 for the gasser.

 

I done my own math and compared it with a calculator. We know the MPG of diesel is better than the gas. However, the question is would it save money over the life of the vehicle and how much. This is only the cost difference in relation to fuel.

So what it came up with (est.) is this.

Upfront cost = $1,500 more for the diesel (BluTec), so can this difference be made up?

Gas prices in my area for gas is 3.42 (93 oct) / Diesel is 3.73 /Difference of 0.31 cents per gallon

Over 1000 miles for gas would be a total cost of $155.45 @ 22 mpg (hwy number)

Over 1000 miles for diesel would be a total cost of $149.20 @ 25 mpg (hwy number)

Difference is $6.25 less than the gas version over 1000 mile period. At the 10,000 miles period its a total of $62.50 saved over the gas version.

The bad news is at 10K miles Adblue (diesel) comes into the equation @ ($32/gal = $224)

or

DIY ( $8/gal {read online, not sure if true} x 7 = $56 plus sales tax = $59)

Cost savings for the diesel are the following:

10K miles + Dealer Adblue service = + $161.50 more than gas

10K miles + DIY Adblue service = - $3.50 less than gas

So conclusion looks like this - If your diesel prices are more than 46 cents more than gas, it will cost you more to have the diesel over a 10,000 miles period.

If your diesel cost is no more than 46 cents than gas, it is a cheaper option to have the diesel. Only under the condition of (owner) DIY of AdBlue service.

With any scenerio if the (owner) allows MB to change the AdBlue the diesel is more expensive.

So, a typical diesel owner that is able to complete a DIY for AdBlue and save $3.50 every 10,000 miles -

After 4,280,000 miles will allow the owner of a BlueTec to amoritize the upfront cost of $1,500 for the BluTec

285,000 yrs @ 15K a year will allow the owner to amoritize the upfront cost of $1,500 for the BluTec.

In another comparison I found that if the cost of gas is @ 35 - 40 cents (rounded and room for error) or more in your area gas is a better option because at the price of diesel gas actually gets better/more mpg per dollar.

A figure of gas is @ $3.50 & (22 mpg) drilled down is for every .05 gallons gas would go .34 miles.

A figure of diesel is @ $3.73 & (25 mpg) drilled down is for every .05 gallons diesel would go .39 miles.

However, if you live in an area where diesel is more than 35 cents (rounded) gas would be a cheaper option as per dollar would allow you to go further. Not on a single tank, however over each vs. cost.

Note: These are variables as every driver gets a different mpg based on how they drive.
Note: These estiments are only based on the 2012 ML350 (4matic) I did not base this on all MB diesels.
Note: These are EPA & MB rated MPG estiments and you may experience better or worse MPG, please do not attempt to degrade the variables with your own specific mpg experience.
Note: Please do not allow this post to differ you from buying a BluTec or a Blueefficiency vehicle as these are only estiments. Base your decision on your specific needs of TQ and availablity of Gas/Diesel or the need for range.