35 MPG in a 1980 300sd!!! WOW!!! - Page 2 - PeachParts Mercedes-Benz Forum

HighDesert Benz · #16 07-04-2008, 01:06 AM

Quote:

Originally Posted by DieselAddict

More salesman BS: '79 300SD hydrogen/biodiesel hybrid. At least he could have got the picture or model right.

http://reno.craigslist.org/car/740538692.html

funny, I saw that picture for a car for sale over in Redding awhile back

. That ad just made me laugh. Not too many vine covered buildings in Tahoe as I recall either

winmutt · #17 07-04-2008, 09:57 AM

You can easily beat 30mpg, if you follow a semi by some 10-15ft.

mslinger · #18 08-05-2008, 08:21 PM

My 80 300SD gets close to 28mpg almost all freeway. 46 miles round trip and it's great only having to fill up every week and a half....

Squiggle Dog · #19 08-09-2008, 12:51 AM

I'd say I'm getting in the high 30s mpg in my 1979 300SD. But then, I removed the AC belt because it robs about 5 mpg, I hear. I would say 35 mpg is about average for one of these cars. I only have to fill my tank once a month, and that is with driving on the freeway to work, etc.

#20 08-09-2008, 04:42 AM

Quote:

Originally Posted by Squiggle Dog

I removed the AC belt because it robs about 5 mpg

With the A/C running it does. With the A/C off it makes no difference at all.

There is no possible way 35mpg can be even close to average.

thesst · #21 08-09-2008, 06:31 AM

Quote:

Originally Posted by Squiggle Dog

I'd say I'm getting in the high 30s mpg in my 1979 300SD. But then, I removed the AC belt because it robs about 5 mpg, I hear. I would say 35 mpg is about average for one of these cars. I only have to fill my tank once a month, and that is with driving on the freeway to work, etc.

You must have a very different 1979 300SD from mine.

I would say there's absolutely no WAY that the "average" for a 1979 300SD (a vehicle with a GVWR of 4800+ pounds) is 35 mpg.

Mine does 22-24 mpg in town, and hasn't really been tested on any long freeway trips yet, so I don't know what that mpg figure would be.

Squiggle Dog · #22 08-09-2008, 11:11 AM

Hmmm... maybe not, but those figures just seem really low for a medium sized diesel sedan. A lot of the heavy American gasoline-powered 1940s and 1950s cars were getting 20-30 mpg, so only getting that much in a medium sized turbo diesel car seems like not much of a mileage improvement. My big 1965 3/4 ton International Travelall Suburban-looking thing was getting close to 20 mpg!

Chadahar · #23 08-09-2008, 11:48 AM

I did an experiment last weekend. There was a GTG for another Forum(MB) Australian Moderator and I decided that I would drive my 560SEC down to Studio City. I gassed up at my home USA Mini Mart. I put in 89 instead of 91 Octane. I have my timing resistor in place.

I drove 65 MPH with the A/C on and the Cruise Control on. Drive was 60-65 all the way to the 101 Freeway on a Friday afternoon. Got on the 101 At about 3:30 P.M. 3.5 miles, then city driving for 3 blocks. 101 was a parking lot for a mile after the interchange then thinned out. My car sat in the parking lot until I came home.

I drove 112 miles RT and topped the tank off the same way I always do and it took 4.973 Gals. to top her off. that is 22.522 MPG! This HOT ROD will get some mileage if I take care.

At 65 you have the road to yourself. those doing 55 are behind somewhere and those goin 80 are out of sight quickly.

I was surprised that the SEC got so good mileage, 19MPG was the best she had done to date.

argus445 · #24 08-09-2008, 08:09 PM

someone should ask how many miles he got his fat #ss and pushed lol

thesst · #25 08-09-2008, 09:49 PM

Quote:

Originally Posted by Squiggle Dog

Hmmm... maybe not, but those figures just seem really low for a medium sized diesel sedan.

Maybe medium SIZED, but very HEAVY.

Quote:

Originally Posted by Squiggle Dog

A lot of the heavy American gasoline-powered 1940s and 1950s cars were getting 20-30 mpg

Lots of those cars were extremely underpowered (esp. in the 40s) and had tiny engines. You go slow enough and you WILL get great MPG, even in a heavy car. In the late 50s/60s/70s, when they actually started adding powerful engines to these heavy cars, the mileage numbers dropped dramatically, with most falling between 10-20 mpg.

Quote:

Originally Posted by Squiggle Dog

My big 1965 3/4 ton International Travelall Suburban-looking thing was getting close to 20 mpg!

What was your 0-60 speed?

Squiggle Dog · #26 08-10-2008, 02:23 AM

True, the cars I am referring to had inline sixes, eights, and small V8s.

My Travelall was very quick. It would do 0-60 very rapidly. It had a high torque International 304 V8 with a 2 barrel carburetor, 4 speed manual transmission, 80PSI tires, no power accessories, Pertronix Ignitor II electronic ignition, Flamethrower II high power coil, I gapped the spark plugs twice the specified gap, etc. I was doing about 20 mpg, but pulling a heavy trailer with another vehicle on back I would only get around 12 mpg at times.

I never use the AC in my 300SD (doesn't work of course) and I rarely drive over 65 mph and try to accelerate and deccelerate smoothly.

thesst · #27 08-10-2008, 03:08 AM

Quote:

Originally Posted by Squiggle Dog

I never use the AC in my 300SD (doesn't work of course) and I rarely drive over 65 mph and try to accelerate and deccelerate smoothly.

That could certainly explain the difference in MPGs... I have a bit of a lead foot

langoley · #28 08-10-2008, 04:47 PM

I get 32.5 on a regular basis in my 1982 300SD.This is on basically FLAT interstate at 65 mph.

charmalu · #29 08-10-2008, 09:25 PM

Yesterday we drove up to San Francisco on 280, light traffic all the way. keeping my speed 60 to 65.
returned home same speed, 70 a couple times on down hill grades. total miles 155 and 5.805 gal. = 26.70mpg.

HMMM. back to the drawing board to get my #`s up.

Charlie