Mercedes Unveils Diesel SLK Roadster With Fuel Economy of Subcompact

Addition to my post: the 57 mpg is Imperial Gallons (note to self: do not read and post late at night). Nonetheless the SLK 250 CDI gets an impressive 48 mpg (US).

In addition, thats the result from the european test cycle which favors diesel engines by very slow acceleration times. The reult from EPA cycle would be about 20-30 % worse, i.e. 36-40 mpg at most.

Rectifier, you lost me on the "fuel economy/slow acceleration times" part. How does slow acceleration this influence gas mileage? You make it sound as if this thing takes a month to reach 60 and thus gets good gas mileage because of this...

When they test the vehicles, the EPA accelerates harder. Thus the conversion between european rated mileage and EPA mileage is often times more then just a unit conversion.

@Willis: when accelerating slowly, the vehicle engine is under very light load. Conventional gas engines have significant pumping losses at light load while diesel engines do not. Hence the advantage for diesel engines in the EU test cycle.

And yes, the test cycle features accelerations 0-19 mph for 10 s, 0-31 mph for 20 s, 0-44 mph for 40 s, etc. More details here:
http://www.dieselnet.com/standards/cycles/ece_eudc.html

In reality, when accelerating faster, the difference in the fuel consumption between diesel and gas cars diminishes.

48 mpg US, 0-60 in a respectable 6.7 seconds (most people aren't drag racing this car) and a nice style with a retractable hardtop. Um, yes please.

New Z4 looks more aggressive, less chick car.