E500 biturbo (M278) cylinder deactivation?
I am from Europe.
I know SLK55 has cylinder deactivation.
Is is the same story with M278 408 HP V8 engine mounted in 2012+ E500?
Because If it would deactivate cylinders, I could believe in declared fuel consumption figures.
I tried, but could not find any info on this topic.
The point is Mercedes claims on its page that E500 is 34.09 MPG (6.9 liters / 100 km ) when on highway.
I have problems believing this figure.
Is it possible with normal highway driving say 75-85 mph?
I am considering to buy 2013/2014 E500 cabriolet.
I wonder what is the real fuel consumption of this car, or a coupe, on highway and in the city.
Cheers

1) There is no cylinder deactivation on my car;
2) There is no 34mpg at 75-80.
The best highway fuel economy I've ever observed was 31mpg @ 69mph average (indicated) on a 1000+ mile road trip using cruise control @75mph extensively. Cruising @ 80mph, fuel economy hovers around 29mpg. I have taken short trips with the cruise set at 60mph and observed ~32-33, but those were very flat roads.
33.2mpg Highway;
17.76mpg City;
The MBUSA site lists it as:
27mpg Highway
17mpg City.
Does the UK have lower highway speeds? If major roads have a max speed of 55mph, that might explain it. 20mph makes a big difference.



