So, I've been thinking about mental experiments and came up with an idea that I've been throwing around.

Everyone wants to put a more powerful engine to go faster, but suppose one goes to the other extreme and accepts poorer performance for possible improved mpg?

So how 'bout putting a 240 (616) engine into say a 1983 126 300SD chassis, making a 240SD, of sorts.

As close as I can figure it, the weight of the 617.95 turbocharged 5-cylinder engine adds about 308# to the weight of a 123 chassis over the non-turbo 4 cylinder 616.

Translating that to a 126.120 1983 300SD chassis, with a curb weight of 3773#, placement of a 616 motor into the chassis would reduce curb weight to about 3465#, still about 250# more than a 1983 240D. The "240SD" would benefit from the 126 chassis' greater aeordynamic efficiency.

My guess is that the performance of the car would be about equivalent at low-speed (city) driving to the 240D, which is, sluggish. But could this yield improved fuel efficiency at higher speed, long distance cruising (60-80 mph), where acceleration is not really the issue, but speed maintenance is? Perhaps the efficiency could be improved by changing the 126 to manual transmission as well?

Ok to say I'm Just an idea I've been toying with for the last week that I wanted to share.

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Der Panzermann und Fraulein Fahrvergnuegen

1991 420SEL 201K "The Big Blue One"
1985 300DT 205K chassis/285K engine nee California emissions "Goldbug"
1983 300TDT 255K "The Womble"
1983 300 DT 214K "Sea Sprite"-Rear-ended a truck
1983 300SD 285K "The Donor" Gave his life so that others can live
1980 500SL Euro 105K "Der Panzer"