We've been here before! At least this is a sample of fuel economy related posts off Yahoo!:
"I thought I'd throw out some recent mileage figures for general info. This was pretty much highway with some town driving and quite warm temps (+90*F). 2 fillups that I did myself to be sure the tank was full. 362.4 km(225mi); 40.5lt.(8.9cdn. gal.) = 25.3mpg (20.22mpg US) 413.8 km(257mi) 45.6lt.(10.cdn. gal) = 25.6mpg. (20.5mpg US) We traveled at 60-70mph and I think I have 3.69 rear end. How does this compare with others experience ?
Richard: 1971 280SL, 4 sp manual, full of emission devices: New York City, about half city and half 55 mph highway: 15 mpg.
Tom Sargeant: 20 US MPG is pretty strong. Couple of questions: auto or manual trans? Any US emissions controls? Top Down or Up? Hard Top on? Engine been rebuilt? Here are some stats on one leg of my trip to Columbus Ohio. I used a hand held GPS navigation unit to capture average speed and mileage, so I am reasonably comfortable with the accuracy: Trip report (return trip only-messed up my navigation on the way up):
Total miles (one way): 435.0 miles
Average Speed: 66.5 MPH
Mileage: 15.1 MPG
Moving Time (FYI): 6 hrs, 31 minutes
Auto Tranny, 71 emissions control, top down, AC Off, wind screen on. Engine is original except new cam and rocker arms. Valve lash reset recently at (inches) .007 and .003. I know that my timing was not quite set right for the trip, and I think I used about a quart of oil over the 900 mile round trip.
John Hassle: my average mileage over 6,400 miles was 18.1 MPG (US gallons). My average speed on interstates/freeways was about 67 MPH (with spurts up to 90 - for passing, of course). Engine was completely rebuilt about 2,800 miles before the trip. Oil and filter were changed the day before the trip began. Total oil consumption was about 0.75 US quarts over the entire trip (essentially a new engine). Transmission: 4-speed manual. Hard top on. Tire pressure: 30PSI. AC: used about 25% of the time (Fridgeking converted to R134a). Cruise control used virtually all the time on long stretches of freeway; overall about 50% of the time. Basic theory of gas mileage: Mileage is inversely proportional to weight of foot.
Dan Caron: I got 25MPG ( about 20MPG American ) in a 250SE Coupe once with four
people and a nice steady 3,000 RPM. That is until the engine blew up.
Cees: I get consistently around 17 MPG (US) or, in european terms, around 7,5 km to each liter. That's with an automatic 280 SL (no emission controls) and a 4.08, now 3.69 rear-end (I have the 3.69 in for a few months now, but I don't notice much difference in mileage terms). My engine is tired and needs a rebuild, consumes oil at around 1 liter per thousand km, yet runs strong and not fuel-inefficient. I drive mostly highway, at an average speed of around 75 MPH. From looking at an official MB publication (I believe the BBB) it shows that the mileage is influenced very heavily by how fast you drive. So a hint could be: try a tankful driving around 10 MPH slower than you normally would, you should see a noticeable improvement in mileage. I understand from other owners that 16 MPG is not unusual at all.
Cees: when I limited my top speed to around 65 MPH (rather than the usual 75 MPH) my fuel mileage went from 1 liter per 7 km to 1 per 8. I think that equates to going from 16.5 MPG to 18.8 MPG (USA gallons).
Bob Smith: that is really good fuel economy. I am doing an ongoing Economy study for my 250SL. Let me tell you I think my car is a "PETRO-HOLIC". Recently I did a short trip to the country (140 miles) and it guzzled its way through 44.73 litres. It returned 11.85 US MPG OR 5.04 KM/L and that was an improvement on the economy from the previous trip, when it returned 9.28 US MPG or 4.56 KM/L. I think it is in tune and not running rich. The exhaust is clean and has that nice dull charcoal colour. There is no petrol smells from leaks. My car was not being driven for almost 2 years before I bought it this June, so maybe as I drive it more it will clean out and the consumption will change for the better.
I drive my 65 230SL (4 speed) regularly and estimate my around town gas mileage to be about 12mpg. I don't necessarily horse the car around, just drive normally. On the highway probably 15-17mpg. Other cars of this era also got lousy mileage.
For the better part of 150,000 miles, covering 32 years - with the old-style leaded fuels and with the current types - I have consistently gotten @ 11-13.5 MPG (US). I will admit to driving the car a bit faster than the average car on the road, and accelerating quickly, but it seems to be returning the same range of fuel useage more or less regardless. When running fast over uncrowded highways (@ 75-85 MPH) I do use a bit of oil as well, though nothing too serious (and well less than the guide range in the owners manual). Frankly, I cannot imagine getting over 14 MPG, unless one drives like my Aunt Lucille!
Albert - I have just done a travel of 2.850 km (around 1.780 miles) in 6 days. Most of them (2.350 km) by highway at cruising speed between 110-130 km/h (69 - 81 mph). The average consumption was: 10,8 liters/100 km (21,8 mpg). The total OIL consumption was 2,8 liters (1 liter per 1.000 km), is it normal? The engine was rebuilt 6.000 km (3.750 miles) ago. Someone told me that these engines usually consume some oil even from new (in the owner's manual you can read it), but another Pagoda owner (250 SL) told me that his Pagoda consumes much less oil ?? I drive my car usually on twisty roads and highway at higher speed, and then the fuel consumption is around 13 liters/100 km (18,1 mpg). Regards, and don´t worry about the fuel consumption: we enjoy each liter/gallon we use!
Cees Klumper in Amsterdam
'69 white 280 SL automatic
