Consider that the 240D only has 67-72 bhp and is running near redline almost all the time during highway commute. Getting 25 mpg is extraordinary.

Take a W123 300D. To be equivalent to the 240D in rpm's, it would have to be going 120 + mph and getting 25 mpg(the 300D would need 180 + bhp to get to 120). 3.69 diff. vs 3.07.

Take an E320 CDI....It would have to be going 156 mph in 5th with it's gearing. I doubt even the 320 CDI gets 25 mpg at those speeds.

Plus the 240D is pushing back a lot of air, too.

I think you fellows ought to realize that the fuel consumption required by a diesel engine is largely a function of the work that it is doing. Not much fuel is required to run it at 3,000 rpm under no load.

That being said, whether you have an OM 616 or an OM617, the fuel consumption is based upon the horsepower required to push the 123 through the air. The engine in the 123 is largely irrelevant if one compares the four cylinder to the five cylinder. The vehicle will require something like 15 hp at 55 mph. This will consume a specific amount of fuel in either engine.

Now, if you switch bodies to the W126 or the W210, then the fuel consumption changes because of different drag coefficients of these vehicles.
With regard to the W210, you also have a more efficient engine when compared to the older engines. This also applies to the W126 equipped with the OM603. If I keep the speed down to 65mph, the SDL will get a steady 30 mpg. This is striking considering that the body is larger and heavier than the 123.

My problem even with the new found power in my car is that I still burry the pedal while driving it. I'm back down to 24-25 mpg's with my 300DT because of that.

__________________
DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

hello folks,
been keeping a spread-sheet on my benz since may. The lowest mpg I've seen is 26.07, and the highest is 31.93. When I first bough it, installed new shocks, and changed the oil. since then, drive it and change the oil @ 3,000. This rig is in really nice shape, killer road rig.

chip

My '85 300td gets a steady 28 mpg. City/highway makes no difference it seems. I do run it easy unless necessary to hammer down and then I leave 'em in a fog.

Cheers,

Bill