And here I thought I was increasing my gas mileage... - Page 4 - PeachParts Mercedes-Benz Forum

kerry · #46 06-06-2011, 12:41 PM

Quote:

Originally Posted by thayer

27mpg is what I got after religiously calculating aproximately 72 thousand miles of mostly highway driving. .

Amen, brother.

tbomachines · #47 06-06-2011, 01:02 PM

Quote:

Originally Posted by kerry

22-25mpg isn't crappy mileage. The 617 in the vans (209d-409d) gets around 16mpg.

Kerry I'm not disputing what you've listed as standard mileage as I know most members get 22-25 regularly. I cite crappy in relative terms to my regular highway mileage to address Tango.

tbomachines · #48 06-06-2011, 01:04 PM

Quote:

Originally Posted by funola

FWIW , in the Mercedes technical data document 00-040, for modesl 123.133, 123.153 123.193 fuel econony was listed as:

city 27
hwy 33
combined 29

Maybe our cars are just worn out along with the MPG drop?

I would imagine this is not U.S. gallons being MB tech document. w126 should be slightly better as its more aerodynamic and different gearing.

edit: Funola you beat me to it, I just caught your post on the last page saying the same

Orv · #49 06-06-2011, 03:16 PM

Quote:

Originally Posted by vstech

I truly think 35mpg is achievable, but only with STRICT driving habits.
you'd have to tune the IP for mileage which would result in a REALLY weak driver. you'd need Thin SMOOTH tires, and brakes adjusted for ZERO drag. the turbo would need the wastegate set back to like 4 or 5 psi, and the car would need to be on the freeway the entire duration of the test, on level ground. with NOTHING in the cargo area but a thin driver.

I think I can buy that.

I touched what I believe to be an honest 28 mpg in my '81 300TD recently. But...it was a long trip at mostly constant speeds, mostly on secondary highways so I was cruising at about 55 mph most of the time, and the IP was under-fueling due to the usual age-related pump issues. Also, wagons generally have better aerodynamics than sedans -- the airflow detaches more cleanly at the rear. (The notch-back profile of a sedan tends to trap a drag-inducing vortex.)

In theory the turbo should increase efficiency on a diesel, not decrease it; the reason turbos usually see lower fuel economy is people use the extra power.

VW for a while was selling an EcoDiesel engine with a low-pressure turbo and no boost enrichment, to take advantage of the increase in fuel economy and reduction in emissions.

In mixed city/highway driving I usually get low 20s. I consider 25 mpg a reasonable average for these cars.

vstech · #50 06-06-2011, 04:37 PM

of course a turbo increases efficiency. just not fuel economy by itself.
put a turbo motor into a car designed for non turbo, and change NOTHING else, and you will get worse or same economy.
now, take that car, and give it a taller geared differential, and do other things to take advantage of the better horsepower, and you have a better mpg vehicle.