Having averaged 44 plus MPG in a 190D 2.5 (OM602 NA which I modded to a more "Euro" intake system) over 14 tanks of fuel, in mixed driving with no freeway, im pretty sure a 124 diesel wagon with the same motor and similar mods could come close. Its only slightly heavier, but also slightly more aero.

3,582.5 vs. 2,845 is a bit more than "slightly heavier" !
the wagon has the sls pump running, it's wider, taller, and all around bulkier than a 190... it's also got wider wheels... and heavier wheels...

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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!

W201 diesels can crack 40mpg although usually that requires a manual transmission.

You'll never get a W124 wagon with an OM603 an automatic tranny anywhere close to 40mpg. The best valid numbers I've ever heard of on a 124.133 sedan were around 34mpg and the wagon will be worse, not better.

Come on you guys lets get realistic here. Not once did I say 40 MPG with the 603 and and an auto. Ultimate fuel economy needs to be approached with a wider visual perspective, smaller engines with less cylinders, not larger engines with more, give greater economy. Pumping losses and cylinder friction go up exponentially as you add cylinders. The OM601 2.2 motor, turbocharged and aftercooled, coupled to a 5 speed and geared properly, would offer the greatest economy, and driven correctly would probably EXCEED 40 MPG. It all depends on how much "oomph" y'all need.

Some other things. I found the 190D 2.5 listed at 3045, and the 124TD at 3450, so we should be able to agree on around 500 pounds difference, not a great amount IMHO.

The SLS pump can be eliminated with springs, and the system removed.

Station wagons from every manufacturer in the world, have historically shown lower drag coefficients. It has to do with keeping the air flow steady over a surface for a longer period. I will admit I do not know the Cf of the 124 wagon, but the 124 has a better Cf than a 201, so its not difficult to imagine the drag HP of the wagon being pretty close to the 201 sedan.

We should all remember that we in the US do not get the small diesels in these cars that were offered in Europe. Over there you could have a 124 wagon with a 2.0 OM601 with a 5 speed. No one here would even want to drive such a slow beast. Well, not enough of us to have made it worthwhile.

But just to make the point, the W201 2.2, as it originally came to the US in 1984, before California and the Feds choked it of air and fed it its own exhaust, was noted for reaching 55 MPG! I wonder what that setup could pull off in a 124 wagon?

Yes, let's get realistic indeed: The OM602 in the 124.128 sedan tops out at around 34mpg with an auto tranny, and around 36-38mpg (maybe) with a manual trans. Putting that powerplant in a wagon still won't produce 40mpg. Ditto for an OM601. Removing SLS is an even worse ideal, especially on a wagon. I also find it interesting that I've not heard of a single person in the USA trying to install a smaller motor into their 124 diesel wagon.



The W201 / OM601 2.2L (201.122 chassis) never got anywhere near 55mpg even with the manual trans, regardless of USA vs Euro specs. I owned that exact car and it was capable of around 40mpg, but not 50mpg. EGR and Federalization was not responsible for a 15mpg loss. The 201.122 simply never got close to, let alone above, 50mpg. That's almost beyond VW TDI territory. You might be able to hypermile a 201.122 with manual trans to mid- or possibly upper-40's but I'll eat my hat if someone can get a mostly-stock W201 to 50mpg, let alone 55mpg.



FYI: The official gov't fuel economy ratings were:
1985 190D 2.2L, manual trans: 31 city, 39 hwy
1985 190D 2.2L, auto trans: 30 city, 33 hwy
1986 190D 2.5L, manual trans: 29 city, 37 hwy
1986 190D 2.5L, auto trans: 30 city, 34 hwy
1987 190D 2.5L Turbo, auto trans: 28 city, 32 hwy
1987 300D 3.0L sedan, auto trans: 25 city, 30 hwy <--very realistic numbers, I've owned three of these
1987 300TD 3.0L wagon, auto trans: 23 city, 27 hwy

Look, I really dont want to argue the point with you, but I averaged 44 MPG out of my 602 powered 201, through more than 14 tanks of fuel. A few minutes online can find various references to the "early" 601 (1984 only) powered 201 with 5 speed manual reaching 55 MPG, and that has been common knowledge since the car first showed up in 1984, almost 30 years ago. From 1985 on the 601 602 and 603 motors were almost completely choked of air by the EGR/intake system (different intake manifold), and fuel economy dropped significantly compared to their European counterparts. In my case, on my 602, I opened up the intake manifold and blocked the EGR, basically returning it to Euro spec. Fuel economy and low end power jumped significantly.

Mercedes-Benz OM601 engine - Mercedes Wiki

Read the 6th paragraph, recalling that those numbers came from the 1984 model

I have a difficult time believing that your OM602 car is averaging 44mpg, especially "in mixed driving, no freeway". There are a number of reasons why your data and/or calculations may be incorrect but it would be a waste of time trying to figure it out when you are convinced you are getting 44mpg.

Also, your OM601 Wiki link has NO REFERENCES. Someone stuck the number 55 in there and who knows where it came from. There are no citations/references for any part of that Wiki article. They claim it was "EPA" numbers of 36 city and 55 highway, but I already posted the official EPA numbers above which are clearly different. Not to mention that the numbers don't make sense, cars do not gain over 50% in fuel economy between city and highway operation. I'm calling "typo" on that one.

I dug up my records from when I owned my 190D 2.2L 5-speed manual. Most of the time it was getting mid-30's, the best ever tank was a bit over 40mpg on a long freeway trip. Now, I'm willing to concede that it may not have been in perfect tune (this was 1994, btw) but even so, I wouldn't expect it to get better than 10-15% more (44-46mpg) and that would be a stretch.

Reminds me of a guy with a 1987 300D on a different forum a few years ago, who was claiming abnormally high MPG (around 40mpg, IIRC). After asking many questions it was finally determined he was estimating his MPG number based on the position of the fuel gauge needle vs the odometer reading. I did find one report from one person who essentially hyper-miled a 201.122 to a peak of ~50mpg (not 55) but that was over a partial tank of fuel, with a few other questionable items (like a replacement transmission that may or may not have had the correct gear ratios, inaccurate odometer readings, etc, etc).

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I see. So the fact you cant get good mileage, nobody else can either, and were all lying? 14 tanks of fuel, not one, not two, 14 of them, and all of them filled after the low fuel light came on.

You also want to suggest the EPA numbers are "gospel", and written in stone?

You also want to suggest the 1985 up US cars are equivalent to Euro cars?

I am sorry, but I would suggest you spend a bit more time doing some research, and stop comparing your results to everyone elses as though your results are the only ones worth noting. At almost 55 years old I have been calculating miles per gallon for over 40 years, and know quite well how to figure it out. I also can beat almost anyone else in mileage with the same car.

When I first got that 190, it was an automatic and struggled to get 25 MPG. There are a lot of factors that often go overlooked, not including a good timing chain with proper cam and injection pump timing, and good injectors. But diesels need as much air as possible to run efficiently. Choking a diesel of air, and dumping such a massive amount of exhaust into such small engines, it reaches a point where you have to ask why you even bother. Its rather rediculous to drive a little car that struggles to get 25 MPG thats also a slug to drive.

I didn't say that. You firmly believe your numbers are correct. I don't. That isn't saying you are lying.



No, I did not suggest that at all. But the EPA numbers tend to be reasonably close to reality. Your numbers are significantly higher.



The differences are much less than you are implying, at least for the OM60x engine family. The differences vary depending on the exact year, engine, and model. Not all MB engines were neutered before coming to the USA. Some gas engines (the M117 is a good example) were choked dramatically to meet US emissions. The OM60x were not. Many MB engines in the 80's and 90's were identical in both USA and Europe.



Maybe you should stop posting inflammatory claims and just enjoy your Prius-beating fuel economy. And I never said my results were the only ones worth noting.



Yep, and you are also claiming numbers that exceed what pretty much everyone else on the forum is reporting. I'm not saying your numbers are impossible, but I am saying they are improbable.

YOU, sir, are the one who lit the fire with the claim that a 124 wagon could get near 44mpg with an OM602 non-turbo.

No, they are as I have stated, as different as night and day actually. Also, if your going to quote me, at least get it right. I never said 44 MPG in the wagon, I said 40, and I said it was "possible", and I said with a 602 NA engine, not the 603 turbo I keep hearing back, and not with an automatic. The 602 turbo might be able to pull it off, but that EGR/air bypass system would have to be altered/deleted. These engines can never get good fuel economy, and never could, starving for air.

It may be of interest to that the present owner of my old 190D (which was modified as I stated earlier, is getting the same kind of mileage I was getting while I owned it.