Hello All,

Im new around hear, so what a way to start off than a controversial topic. Mileage gains and modifying your car. I have just started my hunt for an 80's or earlier MB Diesel. Im not looking for huge gains, but have helped with VW and Ford Diesels in the past to help with small mileage gains.

These are what I have done in the past with my and buddies cars/Trucks:
Block off EGR and clean out manifold
Run Synthetic oils
Improve the intake airflow, better intake
Improve the exhaust flow, straighter larger exhausts pipe
Over all tune up, glow plugs, filters and such

In general Im looking for that 30mpg mark, but see that most report in the mid 20's for the older MB's. If nothing else I think these will at least help to reduce restriction on the airflow for the car. Any input?

Brian

 

Thank you so much. The helps a lot, takes down the work load and cost of stuff I was going to do. For the EGR, do most of the older MB have kits that are easily found?

Thanks

 

[QUOTE=ForcedInduction;158824]Standard practice.


Quote:
Originally Posted by k7bpg
Block off EGR and clean out manifold
Run Synthetic oils

Standard practice.

I have an 80 300D. When you say 'clean out manifold', what exactly do you mean? How do you do that?

Also, you said the 240d was slow, slower than a 300D? My gosh, its the slowest car I've ever owned. Love it though. =)

 

ForcedInduction,
if I do all that, ie remove the intake and clean it out. Close off the egr. What benefits will I incur? I'm not the sort to fix what isn't broken. Rather not risk breaking a stud or stripping out treads removing an intake that most likely has been on the car for 32 years, for something with minimal gains in return.

btw, thanks for all the responses. Much appreciated.

 

"Better fuelmileage, longer engine life..."
I have an '87 300D Turbo with 233,000 miles on it. On the interstate, driving 80 mph max., I average 29 mpg. in suburban driving at slower speeds I average 30 -31 mpg. The time of year has a lot to do with it too. If the AC is worlking hard, it will cost you and 30 mpg will be the most you can expect during hot summer months.
The turbo boost will will overcome restrictions in the intake and exhaust. More important is that that you have unrestricted fuel flow (strainer, filters, colapsing old rubber fuel lines etc.) and no air leaks in the fuel lines to the engine. With mine it is pretty hard to resist not to letting it run, so teach yourself to allow the A/T to shift early, keep the RPM below 3000 and you'll get 30 mpg too, that is, if you have an 87 300D Turbo like I do.
I owned a 300 D in the 70s and the best I could do with it was to average 27 mpg. In 1996 I bought a new 300D and it averaged as much as 34 mpg. We once made a round trip through the Smoky Mountains and back home on one tank of fuel. When I 'gassed' up again we had driven 712 miles! The tank held about 21 gallons total. Took less than that to fill it up. And for most of the trip there were four of us in the car too. We had gone to take in the fall colors and with the football season in full swing, could not find a place to stay over night. :-)))
A warning for those who want to repeat an exercise like this. From our home in Georgia to Nashville, TN were I go on a regular basis it is 275 miles. Most of the route is on the intestate and I set the cruise control on 80 mph and usually do it in four hours, if I don't run into traffic delays.
On my last trip the reserve light came on at 490 miles. I figured I had a good 75 miles left. Next day I drove into town to fill up on my regular pump. Surprize, the car ran out of fuel at 556 miles, going up a long hill! I must have had at least half a gallon left, but going up on that hill the engine started to suck air and stopped.
Luckily I was able to roll back down the hill to a level spot. I had with me a quart of engine oil and put it into the tank. It took a while to get the air out of the fuel system. The engine eventually got going again and then ran as good as ever. :-))) (edit. 8/31/12)

 

agree with forced induction on all points but I would add a few based on the many diesels Ive had and still have.
1. new timing chain if there is sig stretch to restore proper advance.
2. I added bosio nozzles to my 300 turbo. I always got 27-28 mpg hwy and I am now 2 yrs later always 30-32 and there was a marked power improvement. I drive 55-60 mind you. My 240 D gets 32-35 under the same driving. Both engines are tight, burn no oil, start in winter and have had chains replaced.

 

I agree with Forced, the Germans used to know how to build things. leave it original, and tune it up properly, and remove the epa b.s.

 

So basically what I am taking from this thread is that with the way these cars were originally designed; if you take care of the maintenance and don't hammer the accelerator pedal every time you take off; this is how your best mileage will be obtained.

My '83 300SD will average 32 on the freeway with cruise set to 55...

 

I have read some misleading posts below. About Mercedes airbox being as good as a cold air system, and the exhaust system being adequate to get the best fuel mileage out of these cars. That's bunk! Have you ever known a car manufacture to do anything more than just meet EPA standards and the least amount of cost to get by. I have a 1986 190D. I removed the original Mercedes filter closed up the airbox and install a 90° tube with a K&N performance air filter, on the original inlet of the air cleaner box. And then remove the three muffler exhaust system and went to a two and three-quarter inch pipe from the front to the back with a high flow muffler and a turned down tip. The name of the game is airflow maximum on airflow in and out. One other thing I do, I mixed to a half ounces of two cycle outboard motor oil to every 10 gallons of diesel fuel, to counter reacts ultralow sulfur diesel fuel that is now sold. This alone can save you as much as 1.5 miles per gallon. And you'll be surprised how much quieter your injectors are.

Originally I was getting 37 miles to the gallon. Now at 65 mph I'm getting between 45 and 46 miles to the gallon. At 60 miles an hour I'm good day and touching 50 miles to the gallon. I'm a class VIII truck driver I have been practicing fuel mileage since the early 80s. In the early 80s averaging 4 miles per gallon. In year 2012 I averaged 8.6 miles to the gallon the 2004 Volvo 780 550 hp Cummings.

 

Brian, I had my first '64 190d almost 50 years ago and several others since. I now drive an '87 300D Turbo. It's in daily use with 248,000 miles on it. (It's FOR SALE too, $5,000 or my 1998 E320, 166,000 miles, same price, your choice.) I too have been a fuel conservation freak for many years. It's the total cost it really comes down to and that is why I think an old MB Diesel is as frugal an operation as you can get. About cleaning up airflow. This does not apply when you have a Turbo. You get 16# boost and that is as much as the engine can handle. All you have to do next is make sure that there is no problem with fuel delivery and that the air filter is not clogged. My check for that is to step on the 'gas' and watch the acceleration under a load, as when entering an interstate. After you are in third gear, if the RPM marches right up to 4,000, that's good enough. Don't look for trouble. The factory advertised fuel consumption, if I remember correctly, was 29 mpg at 120 km/hr and 3/4 load. Top speed of 125 mph. Slowing down is what increases fuel economy! I have records that show this car will get 34 mpg in suburban driving between 40 and 50 mph. Keep it below 60 mph and you can get 32 mpg. On the interstate with only myself in the car and driving no faster than 80 mph I can get between 29 and 30 mpg, depending on how hard the A/C works and on whether I have head or tailwinds. Diesels require special engine oil, I don't think there is a point in substituting synthetic oil. It's more important to just change the oil regularly. Keeping the oil clean and not running low on it is what matters. My car burns less than a quart in 5,000 miles. I think that this is great, keeps everything lubricated on the way out. :-)