fuel prices/mileage/my experience
I generally average 60 to 80 k miles per year. Since the aquisition of the 600sel (apr 2002), I have tried various premium brands of fuel and tracked the fuel mileage the best I can. Generally speaking, my overall annual mileage is such that the car has to be fuelled every day. What does stand out (on this car), is the fuel mileage will always be best with the sunoco 94. I don't know why, but mileage is consistently higher with the sunoco 94. My driving entails 95% or better of highway, with the cruise typically set at 118kmh (72-73mph), or if on lower speed limit roads, typically 15kmh (10mph) over. What I have noticed is that the difference in fuel mileage between brands (in this car) can be as much as 20% for the same trip (approx same time of day, weather, minimal traffic). I do know from working with the fuel industry, that Sunoco 94 is the only fuel that has its own discrete dispensing system at the fuel terminal/storage yards, and that no other grade of gas or diesel is ever pumped thru that system (in Ontario anyway). I don't know if this is a factor for fuel mileage or not. So far, since owning the car my overall average fuel mileage is 24.7 mpg (imperial gal), with a high of 26.1 and a low of 18.5 (bad day in the city). I haven't tried a lower octane than 91, but from the posts I have read, it sounds like mileage will probably suffer enough to offset the potential short term saving (in this car). I haven't had the opportunity to track the mileage in the sl, but I am curious to see how it fares long term. The better half just has the sl filled and drives it, she doesn't put on enough miles to be concerned.
A mercedes is an inanimate object and therefore must respond to logic and reason.