Proper MPG for '85 300D
 

My 300D recently had a full tune-up and my round-town MPG is about 22. Is that low? I see folks get up to 30 MPG on the highway. Either way, I'd love to have a benchmark.

Thanks!

for an 87 300D maybe, for an 85 no way.

In the summer I get 25mpg city/highway mixed driving.

Now in the bleak mid winter I see between 22-23 mpg. You're results are close to mine.

When I drive to and from college at a speed of 55 mph I got 27 on one fill up, but that's just a number that falls out of the normal range.

For around town 22 is probably reasonable. You would have to try very hard to get 30 on the highway, high 20s is more obtainable.

Charmalu was getting over 30 mpg highway with his '85 before the motor went. He was running very high tire pressures, oversize tires, and probably drives like an old person. I managed 29 and change once in my '83 on a tank of all highway back east following 65 mph speed limits. 22 around town sounds reasonable though.

Low-mid 20's is the same for me on my '85 300CD, mixed city/highway driving here on my part and I have a heavy foot. :D

24ish for me. My 84 gets 27ish with the supposedly worse rear ratio.

Thanks all! Looking good....

Mine gets 25-26 MPG consistently running a B20 blend. 27 MPG on the #2. That is mostly highway driving down US 1 locally with speeds below 65 MPH.

Also, I know exactly what my odometer error is and I correct it when I check my mileage. Before I checked the error in my ODO. I was only getting 22-23 MPG and could not figure out why. As it turns out... For every mile I traveled, the ODO. would only register 8/10's of a mile. Obviously someone replaced the odometer from a different car at some point. That coupled with the fact that car has 205 70 14's on it, gives an indication of bad mileage when in fact it was pretty good.

So.... Be sure you "know your odometer error" (if any) before you start thinking you have mechanical issues. Especially if the car is a recent purchase.

the original EPA & manufacturer rating of the 85 300D is 22-23 mpg. I seriously question anyone claiming more than. But if they do then more power to them. But the original EPA & manufacturer rating of the 85 300D is 22-23 mpg. I'm guessing same goes for all the DT W123s.

Remember, this is a heavy vehicle.

What do you mean by full tune-up? Adjusted the valves? How many miles on your injectors? When was your IP timing checked and adjusted? I don't want to rain on your parade, but perhaps you could be getting better. I know that my mileage improved slightly when I had my injectors rebuilt at 100Kmiles. Ran smoother too. Still need to check timing tho...

You should really read up and learn more about what those #'s actually mean. That does not mean squat in the real world. Every car I have ever owned did not even get close to what they put up on their site. Except the VW Passat TDI and even those #'s were low. Case in point, I owned a couple VW Passat TDI's. Both of them would regularly return 48 MPG and I actually never saw less than 43 MPG. 43 MPG was with 3 adults in the car and about 300 pounds of luggage/camping gear. This was also cruising at 80 to 85 MPH. The EPA rates the car as getting 31 to to 41 MPG. 31 MPG must have been figured with parking brake applied and 8 hours of idling.:rolleyes:


In the end.... The car can only do so much. The rest is up to the driver.

Was that the federal #'s, or the California version (Trap Ox)?

Mid- to upper-20s
 

Our 1983 300CD-T (about 248,000 orig. mi., rebuilt head, California)
In town: About 24-25
Freeway: About 26-27

Our 1985 300CD-T (about 165,000 orig. mi., California)
In town: About 25-26
Freeway: About 27-28

I have been tracking the mileage on every tank for about the last 12 yrs. Not much variation in the mileage over that time.

Drives like an old person, :cool:, well maybe so, I have been called worse :D

I don`t have the numbers before I replaced the automatic with the 240D 4-spd. but they have improved quite a bit since. this is the 85 with the 2:88 Diff.

here are some milages form last April when I started keeping track after the 4-spd. some are mixed, and some are trips to portland, Or, and Carson City, Nv. going to Carson the MPG are less. Iam going from sea level, up over 8000ft, and then down to 4600ft at Carson. coming back home it`s going from 4600 to 8000 ft, then a long down hill mostly back to sea level.

So 27.86 to carson, and 31.94 returning. and that fluctuates some also.

So here is the year in review.
27.86, 31.94, 26.98, 27.89, 29.68, 27.09, 28.40, 30.79, 26.87, 30.05,
32.21, 24.47, 28.18, 26.87, 29.01, 30.18, 32.72, 26.93, 26.81, 29.62,
30.88, 31.94, 27.46, 27.57, 26.29, 28.04, 29.39

I always fill to the brim, rock the car to burp it, and get it to the lip of the filler neck. I do run my tires to the max the side wall has printed on it. I run Big O 205-70-14. stock is 195-70-14. looking at the Miata tire calculator, the 205 are 2% larger than the 195. the tire pressure is 44#.

I do drive with the tack about 3000 rpm`s and doing around 62 - 65 mph. I push it faster, and the mpg drops\
I know some on the forum brag they do 80 to 90+ mph. I don`t know where I could do that w/o sitting on the side of the road chit chatting with some dumb cop.:policeman I would rather be moving and getting to where I need to be.

That`s about all this old Fart has got to say :wheelchair: