By on February 18, 2010

This is a short story of how we sometimes arrive at the truth. Letting go of deep-seated childhood emotional responses is hard. Growing up in the fifties in Austria, Mercedes was my true God. My father had a friend with a 300 SL Gullwing, and I spent hours walking around it, absorbing each detail. There was an old Tatra streamliner in the neighborhood. Aerodynamics, efficiency, and speed are my triggers. In 1985, I bought one of the first W124 300E sedans in LA, in part because its Cd. of .28 was the best in the world then, as well as its 140 mph top speed.  Just yesterday, in Part 3 of the History of Automotive Aerodynamics, I concluded the survey of current production car aerodynamics record-holders with the 2010 Mercedes E-Class coupe, honoring its widely disseminated Cd of .24, lower than even the 2010 Prius. Looking at the picture of that E Class coupe this morning triggered a totally unexpected upsurge of that old lust, something that I thought was long extinguished, and I actually went to the Mercedes web site for strictly personal reasons. I expected that Mercedes would be trumpeting the coupe’s .24 Cd proudly. Not so, and for a good reason.

In fact, there was no reference to it anywhere. I remember how proudly Mercedes was of the W124’s sleekness in its ads and brochures. What gives? I had to download a pdf with technical specs, and there it was, buried in small print: Cd of .28. It’s 1984 all over again.

I found the answer buried deep on Mercedes’ German web site: the .24 Cd only applies to the E 220 CDI Blue Efficiency model, that isn’t even going to be available  until later this spring, and in then in Europe only. It must be lowered and have lots of aerodynamic tweaks. Google “Mercedes E-Class Coupe coefficient of drag”, and you’ll see that every magazine, web site, newspaper and of course wikipedia has repeated Mercedes’ Cd of .24 virus endlessly.

I’m still surprised with that unexpected surge of Mercedes lust; but it came for a reason: I’m totally over Mercedes now, and I’m here to proclaim to whoever listens: the 2010 Mercedes E-Class coupe has a Cd of .28, the same as a 2001 Camry, a 1995 Mitsubishi Diamante, a 2003 Saab 9-3, and a 1998 Chrysler Concorde.

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42 Comments on “The Truth About The 2010 Mercedes E-Class Coupe’s Aerodynamics...”


  • avatar

    And it’s still the ugliest coupe on the market, to boot.

  • avatar
    Audi-Inni

    As a previous ML320 owner, bought new, I got over MBenz years ago. It was the most unreliable POS I have ever owned and (un)supported by a company that couldn’t have cared less.

  • avatar
    ash78

    I’m proud of my B5 Passat’s 0.27, achieved without looking like a science fair project in the process (*cough*Prius). FWIW, the Prius is 0.26 and looks every bit the part of a car designed with aero concerns above all else. I’m not knocking it, but I have long held that its design is just as much about marketing as efficiency. If you want to sell “extreme green,” it pays to package it accordingly. Thankfully, efficient cars are becoming more the norm and the styling cues are much more palatable now.

    Certain simple touches, like the hood seam placed further down the fender (see Merc above), can make a huge difference in regular cars. Underbody aero also plays a very large part, to which my 3 separate plastic belly pans can attest.

    • 0 avatar
      hakata

      The B5 is a paragon of what good mainstream sedan design should be. Clean, functional, svelte, slightly athletic stance, with good visibility and subtle cues, i.e. no chrome bedazzlement. As an example of just how fine the line is, compare the Ford 500 (sorry, Five Hundred) and see how a different set of designers can make the same basic idea look like an old fartmobile.

  • avatar
    RGS920

    So who is going to be the first to edit wikipedia?

  • avatar
    bmoredlj

    That’s okay. Even if it did have a .24 Cd, it doesn’t do anything for me. Looks way too much like a Solara. The rear 3/4 view in particular looks like it’s bending the laws of perspective; not a good thing.

    The fact remains, the Czechs had a more aerodynamic car than either the Prius or Volt fifty years before I was born, which is impressive.

  • avatar
    porschespeed

    Yup, the lower Cd only applies to an ‘efficiency’ that will be produced in limited numbers. Shocking.

    Same old marketing crap that you see in a Chevy commercial when they brag about their mileage vs. Hondota.

    Sure, the Crapalierbalt XFE gets good mileage – wanna drive that third world penalty box? Nah, you want the model that is a bit less horrible, which does suck a bit more fuel.

    If you really want a Chevy badge and all you care about is mileage, you’re gonna go buy a used Geo Metro anyway.

    MBZ got some semi-undeserved free press, and like some “news” outlets, they didn’t really lie completely – they just put out a tiny slice of the truth that suits that particular agenda, while leaving out the other 90% that clearly doesn’t.

  • avatar
    gslippy

    I think the E-Coupe is one of the most beautiful cars in the world.

    But they’re too expensive, too small, and too unreliable (as a make) to interest me.

  • avatar
    OhMyGoat

    Wait, that isn’t the Sebring coupe?

  • avatar
    BryanC

    I’m completely baffled why anyone at all cares about Cd, since it isn’t actually connected to efficiency. The number which actually matters is Cd*A, which tells the actual drag of the car. If one car has a Cd of .2 and an area of 100, it has a drag of 20, whereas another car with a Cd of .3 and an area of 30 has a drag of 9. Cd by itself is meaningless!

    • 0 avatar
      criminalenterprise

      Yup. Cd only tells how good your designers were at making the shape they presented to the wind slippery. It doesn’t give them the deserved credit for presenting less shape to the wind.

    • 0 avatar
      Paul Niedermeyer

      BryanC, Unless you want to make a car that is substantially narrower or lower, in nay given class of cars, the frontal area tends to be fairly similar. The only way to change the aerodynamics then is to improve the Cd. That’s why its been an issue for so long.
      Your comparison of two vehicles, one with an area of 100 and another with an area of 30 is like comparing a Lotus Elise and a Hummer. Talk about meaningless! :)

  • avatar

    I rather like the look of that E coupe, particularly from the angle in the photo.

  • avatar
    werewolf34

    In LA, the E-class coupe is very popular. Sells like crack

  • avatar
    talkstoanimals

    Add me to the list of E-Class coupe admirers. It’s a much better looking car in person than in photos. The problem for the Merc, though? The Audi A5/S5 is even more stunning, and it has a better looking interior to boot.

  • avatar
    saponetta

    I think it looks like a toyota solara. We’ve been selling everyone we get since they came out last summer and its not slowing down.

  • avatar
    mhadi

    Ugly is a subjective thing. Each to their own.

    It is interesting that the Audi 100, which had a Cd 0.30 was ground-breaking and involved a lot of R+D (back then Cd values of 0.40 were common, and the S-class (W126) has a Cd 0.36). Those cars were mass-produced cars that had those Cd values. You did not have to buy a special version of the car.

    It was said that it was almost impossible to lower that number any further, and even the cars that came after it only achieved a Cd of 0.28 or 0.29.

    Now we have cars claiming lower and lower values.

    It is obvious that these are cases of either deception, or extremely limited special editions, that no one would buy, created purposely for advertising purposes.

    I am a fan of Mercedes. It is mainly nostalgic, as it harks memories of the superbly engineered solid cars that had a timeless design. Unfortunately in this day and age you have to mass produce to remain in business, which is why the Mercedes brand has become so diluted in quality, design, and engineering.

  • avatar
    carguy

    Paul: Fair point – it has a Cd of .28 instead of .24 – but do you really think that any of the E coupe’s target demographic rally care?

  • avatar
    Waaghals

    I’m pretty sure most of the 4-cyl Mercedeses being sold where I’m from are so called “blueefficiency”-models. They are normal models that are tweaked to offer better MPG. There is nothing limited or particular special about them, unlike what many people here seem to think. Having said that, it seems a bit dishonest of Mercedes to tout the drag coefficient of a car that doesn’t exist yet .

  • avatar

    “Looking at the picture of that E Class coupe this morning triggered a totally unexpected upsurge of that old lust, something that I thought was long extinguished, and I actually went to the Mercedes web site for strictly personal reasons.”

    Ewww… TMI Paul. TMI.

  • avatar
    Vega

    Two main reasons for that:

    Smaller 2.2l 4-cylinder engine —> less need for cooling, less need for air to be routed through the engine compartment

    Narrower tyres —> less non-aerodynamically optimized frontal area, average cd gets reduced.

    Our run towards bigger and bigger engines, brakes and wider tyres has offset almost all of the aerodynamic advancements of the last 20 years.

  • avatar
    FleetofWheel

    Narrow, slit-like windows do not make for an aerodynamic car.
    Hopefully, car buyers will begin to overcome being fooled by this psycho-visual trick and demand vehicles with bigger glass.

  • avatar
    AccAzda

    I have to say, I used to be fantastically amazed at the cars MB put out.

    The lines were tight and had a purpose
    The front clips were cohesive and looked good.
    And this was only.. 5-6yrs ago.

    Mr. Niedermeyer, I am amazed that you were so enamored with the Cd of the W124 that you bought it.. because of that.

    Now, there isn’t a single Benz that I could be caught dead with. The lines are such a mismash of trapezoid front lights, obese rear clips.

  • avatar
    CarPerson

    Be gentle, people; you’re talking about my next ride.

    I’ve penciled in a 2010 E350 when they start coming off lease in 2013.

    Snow white, please, although I have a pea-green one spotted and I’m keeping an eye on it.

    Local dealer has my number and my requirements: The first one that hits my $27,500 price point wins. Never seen a body shop, all service records, still under a long warranty. I have no deal-breaker “must have-don’t want” options.

  • avatar
    Dr Lemming

    I’d also give the E-Class coupe a thumbs-down vote. If this were a Lexus I’d write it off as typical of the brand. But this is Mercedes, which used to be the gold standard for styling that was both timeliness and was grounded in good engineering. The E-Class coupe is just another bangled mess of awkward lines and a bloated profile.

    It would be cool to see Mercedes once again emphasize aerodynamics — not to out “green” the Prius, but because that’s a major element of a well-engineered car. It would also be cool if Mercedes would return to its German stylistic roots.

    Alas.

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