Our 85 300d was getting around 24 - 27 or so. then when we installed the 240D 4-spd manual we were in the 29 - 31 mpg range on the highway.

Our 80 240D was getting around 28 with the 4-spd and 3:69 Diff. I installed a 3:58 Diff, then aired up the tires to the max, and on the hwy we are getting 30 - 33. even our in town driving is showing at leas 30mpg.

On a trip to Portland Or. from Calif, the 240 fully loaded down, I was pushing 65 - 70 and got 33.5 when I fuel up in Portland.

On the trip back I kept the speed 55 - 60 and when I fuel at the same station, we showed 38.7 mpg. so holding down on the speed works.

The faster a car is pushed, then the milage will suffer.
I would recommend getting a GPS to get the correct miles driven.

There are many factors that will effect the milage from one tank to the next.
Up hill, down hill, head wind, tail wind. summer vs winter fuel, and driving style/habits, engine health...............

Even driving on a hot day vs a cold day will make a difference. cold air is more dense.

I see a lot of far fetched claims on CL and E-bay on the milage.


Don`t let any of us here slow you down on making improvements to your car


Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Concerning the Car weight; with gassers back in the 1970s they were saying if you could get rid of 400 pounds of weight off sprung weight you could save one Mile per Gallon.

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84 300D, 82 Volvo 244Gl Diesel

What seems to be missing from all the Mileage Claims I have read is an accurate Measurement of the Fuel.

Someone needs to draw Fuel from a smaller Fuel Tank that has lets say 2 gallons measured accurately poured into the Fuel tank.

The Car needs to be driving but not to the extent that the it runs the Small tank Dry.

The contents of what is left of the Small Tank is poured back into the accurate measure you used when you measured the Fuel that was going to the Small Tank.

Then you figure out your Mileage based on the amount of accurately Measured Fuel used.

It would also help if the Fuel was the same temp at the beginning of the test and the end of the Test because the Fuel is going to get Hot from cooling the Fuel Injection Pump.

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84 300D, 82 Volvo 244Gl Diesel

If you read my "SD fuel economy challenge", you would know exactly the conditions required for an honest evaluation of fuel economy.

Four successive tanks...........minimum of 10 gallons per fill...........averaged.

Any other claim is worthless.

FWIW, the SD has now dropped back from about 29.5 to 28.0 for reasons unknown. Driving style and distances traveled are identical.

same (rebuilt) engine, in 1 inch lower car with better aerodynamics (w126 coupe)
30kg less curb weight...and I can only dream about 33 mpg.

@75mph (my) best case scenario is 26 mpg.

I have factory sprintfilter cold air,and I have not see any power increase.


cheers
ChO


.

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w126 500SEC gen II euro, powered by OM617 turbo stolen from 84 300SD 2.88 diff,EGR blinded
next wish/project: w114 coupe OM603 powered

it may be "bad fuel quality" magic..... maybe...


.

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w126 500SEC gen II euro, powered by OM617 turbo stolen from 84 300SD 2.88 diff,EGR blinded
next wish/project: w114 coupe OM603 powered

What have you done to your car to get this?

this claim is very much outside of the norm for the vehicle, so Please post what you have done to get this.

anybody can get 30+mpg out of the vehicle if the trip is all downhill, with a tail wind, highway all tank long, and no stops between fillups.

the trick is averaging above 25mpg from tank to tank. accurate fills of the tank, burping out all the air, (why is it SOOOO hard to get the tank full to the brim on these cars???) the last 2 gallons or more take FOREVER to burp out the foam!

the problem is the car's designed in the early 70's/late 60's before aero was factored in. the flat nose, and bulbous bumper with high front and rough underbody do not promote efficient speeds above 60mph. add in the heavy automatic transmission, without any lockup the heat and slippage add up.

aero up the front end, and all panels, and the wheels/tires, and the underbody, and lighten up the load, carbon fiber all the skins, change the rear end ratio, get a smaller fuel tank, plastic race style, and swap in a 5 or 6 speed overdrive manual transmission, and you could see 40... or more even I suppose...
but then it's not a 123 sedan anymore...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

If you want to get rid of the stock bulky one there are several options-but the stock filter design really is solid.

Adjusting your ALDA in the non-performance direction would definitely net you some MPGs

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

My car has averaged about 27 but we have been buried in winter. Lots of cold starts. My best one tank was 32 mpg in November or early december in more moderate weather.

Probably a factor of the fairly olds cool transmission as my car doesn't coast well. I run 50 psi in the tires. I am hoping for constant 30+ mpg once the weather warms up.

It takes a lot more driving skill to get good mileage than it does to drive fast.

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85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.

Here at peachparts diesel discussion we don't fall to the claims of 30+ MPG without proven data and methods so that they can be repeated.

Science, it works....

I measure my mileage the conventional way Don.

Drive until I need gas then fill tank and calculate it. I do it for every fill to average out inconsistencies

Here is a graph of what I have compiled during midwestern driving this winter so far.


I am pretty sure that my car should get 30+ mpg when not battling snow and ice.

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85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.

on a trip that will total around 2500 miles; Richmond - Tampa - Miami - Richmond. Leaving mid-April, returning last week April. I'll maintain a precise fuel log and get back to you-all in a separate posting.

Right now I am getting 26 to 28 mpg in mostly rural driving. The only mod that could affect fuel mileage is EGR delete.

I used to get ~30mpg after I properly adjusted IP timing, but since then I've screwed around with it too much and if I'm lucky and wait until I travel at least 360-380 miles between filling up I can get 21. I guess I should probably get the timing adjusted back to where it was lol

PS-can somebody tell me the trick to getting that nut between the IP and the block loose? Something tells me u need to use extensions and u-joints and socket and ratchet instead of a regular old wrench

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1982 300D Turbodiesel, daily driver. Mods so far: Fram 8038 paper filter, 4 brake light mod, Gen II w126 (front) rotors/calipers, boost turned up to 12lbs, non-egr manifolds, water/methanol injection, 4-speed manual
1980 300SD Turbodiesel, project car, nearly ready to hit the street

1974 240D, New paint

Here is a fuel map for a 300SD

Note that it takes about 20KW to go 60 mph and that translates to 300g/kwh or 6kg per hour. Diesel weighs about .8kg/liter so that is 7.5 l or about 2 gallons per hour at 60 mph or 30 mpg. Interesting the curve is flat until about 3600 rpm

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85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.

I know you believe your test is sufficient.

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84 300D, 82 Volvo 244Gl Diesel