Why Mercedes Benz 'boxy' cars are more aerodynamic than 'sporty' Japanese ones?
 

A. Is it because MB has better design tools like wind tunnels, superhigh speed computers for CFD, top aerodynamicists, etc?

or
B. MB can afford to produce more complex body shapes. Maybe aero shapes can't be formed in the so thin sheetmetal usually found in Japanese cars? Even if aero shapes can actually be made in thin sheetmetal they require more complex molds and robots that only MB has?

You can even add
C. MB rear wheel drive allows for a lower hood line. Maybe also better internal aerodynamics after air passes thru the radiator? Although modern MBs have a quite crowded underhood space.

I thought japan and korea had boxy non aero vehicles?

i havent been under alot of older mercs, but i think all the cars for atleast the last decade have had full underbody paneling. i dont know when they started doing this, but i imagine they gave the underbody consideration well before they covered em all up

Europe has CO2 taxes, Japan does not. There's less reason for Japanese cars to be economical.

'Sporty' cars with curves are generally poor aero-wise.

The GT-R is quite boxy and very good aerodynamically, it matches the 'boxy' B Class Eco Package.

But the Mazda 3 sedan is quite curvy and matches the 0.26 of the other two.

Basically, it's 'A', but I don't think this topic has any real merit.

Do you have examples of each so we know what we're comparing?

I doubt it's 'B'.

Fuel is somewhat expensive in Japan (at least compared to the US). They have a displacement tax but that's a bit different I guess.

I think the biggest reason why a lot of Japanese cars don't have great aero and have short gearing is because Japanese people don't drive many freeway miles, so it's not worth it for them to build highly aerodynamic highway cruisers.

Not sure of the premise?

Lexus LS is a boxy Japanese car with a low Cd.

Take this quiz Name That Eco Car! Aerodynamic Vehicles - EcoModder.com it seems the Japanese are fairly well represented.

Perhaps the "sporty" ones you are looking at are sacrificing Cd for downforce.

I can't even think of any sporty Japanese cars nowadays... and even less with poor aero.

Also... Mercedes... boxy?

http://www.saudishift.com/wp-content...-1-profile.jpg
http://image.motortrend.com/f/wot/ma...pt-profile.jpg

I have absolutely no idea what you're talking about...

http://o.aolcdn.com/commerce/images/...nt_Regular.jpg

http://static.cargurus.com/images/si...wnsize=482:299

Mercedes' really low-drag cars are only specific variants of cars with typical Cd (for example, the CLA in American trim has Cd .28, while the BlueEfficiency version available in Europe is much lower at Cd .22). Meanwhile, the Corolla (Cd .28), Prius (.25), Sentra (.29), Mazda6 (.26), FR-S (.27), Camry (.28), Mazda3 (.26), and Avalon (.28) have drag coefficients well in line with what Mercedes and other manufacturers are producing, if not lower than what some are doing (*cough* Chrysler).