New world's best Cd for a current production car: 0.24, Mercedes 2009 E-Class coupe

[MetroMPG]

And they did it in a pretty conventional-looking car:








On top of that, the engines (available in Europe, at least) are 17% more efficient than the previous model.

From the official press release:

...The most aerodynamic variant of these coupés achieves a new world best in terms of drag coefficient: with a Cd-figure of just 0.24, this model is the world's most aerodynamically efficient series-production car.

...

The best example is the twin-turbo diesel E 250 CDI BlueEFFICIENCY Coupé, which consumes 5.3 litres of diesel per 100 kilometres (44 mpg US / 53 mpg Imp) and emits 139 grams of CO2 per kilometre, making it one of the most economical vehicles in its class.


This exemplary low fuel consumption rate has been achieved not only been because of the new engines, but also due to a number of practical measures.


These include on-demand activation of the steering and fuel pumps, the use of tyres with low rolling resistance and an alternator control system which takes account of the current driving situation and the vehicle's electrical power requirements, plus the very important contribution made by outstanding aerodynamics.

source: New Mercedes-Benz E-Class Coupe Revealed Before Geneva Debut - worldcarfans

[Daox]

Impressive. Now scale the car down so it weighs around 2000 lbs and throw a ~1.0L diesel in it and let me drive to my heart's content.

[MetroMPG]

I'd like to see a plan view. Looks to me like there's quite a bit of plan taper in the greenhouse, from that front 3/4 shot.

And I haven't found it yet, but we can probably expect an article from Mercedes about the aero development/testing, including whether they used any new tricks (like their "aspirated" tail lights to promote clean flow separation at the rear).

[NeilBlanchard]

Hi,

That upper grill must be (mostly?) blocked off, and the only other thing that jumps out at me is the lack of a 'B' pillar. And, they probably did an excellent job on the underside of the car, too.

[brucey]

Pretty conventional looking except for the no B Pillar. Which I kinda like. Go benz!

[lunarhighway]

what i think is one of the tricks is a pretty slim behind.
the taillght run quite a distance across the sides which is a aft/side view give the rear a much broader appearance than it actually has. in the second picture you get the impression the left point of the taillight is the outer edge of the booth, while in side profile view it appears to extend almost all the way to the C pillar.

and in the front/side view... it's completely invisible, meaning it's "behind the bend"

this car has some serious boattailing going on, which is cleverly hidden.

another perhaps less successful example is on the opel insignia... with 0.27 it doesn't do to bad, compared to most cars today (keeping in mind it's a 4 door saloon and hatchback... and an opel.... not a merc coupé)

sideview... again, no merc, but it looks more than ok to me

early spy shot from a slightly different angle

side rear view

there might be some telelens distortion in this picture, but you can see it's got a pretty narrow rear for such a big car. something appears a bit odd from this angle...

while in a more human perspecive, and no doubt heavily photoshopped official view it looks like this


since most people still associate the broad rear tires of and f1 or drag racer with a power-full fast car, a narrow tail, the to us so beloved "boattail" looks odd to them. but "odd" shapes can be visually camouflaged to produce a "normal" looking car. especially when cars are usually seen from a normal persons height... how often for example do scale drawings include a top view... let alone a bottom view... we simply don't thing of these views as part over the overall picture (while that's where a lot of the aerodynamics, or lack thereoff become apparent)

anyway, i think the guys at mercedes, and hopefully stylists everywhere, have truly mastered their art so that they can totally disconnect the way we see the car from it's actual physical shape and dimensions.

the lack of a B pillar reinds me of my dad's rekord coupé when i was a kid... it was great fun in summer to crank down all the windows... although doing so probably decimated any aero advantaged the coupé roof had

[MetroMPG]

Originally Posted by lunarhighway

this car has some serious boattailing going on, which is cleverly hidden.

I suspect the same thing. It'll be interesting to see some top down pics, or one in person.

Regardless, WAY TO GO Mercedes for ratcheting up the game. I love to see automakers competing on this front... for aero bragging rights. In a competition like this, everybody wins.

[MetroMPG]

ABG photo gallery of the new Merc: Autoblog

[Frank Lee]

Blunt!

[MetroMPG]

No thanks, never touch the stuff.

But just imagine how slippery it would have been if they'd made it POINTY!