Realistic MPG in 300D's, 300SD's, 190 D's? - Page 12 - PeachParts Mercedes-Benz Forum

Screwdriva · #**166** 08-28-2019, 07:25 PM

Quote:

Originally Posted by barry12345

Anything of a modification?

Other than the list above, the only other thing I can share is that the car was mechanically fully restored. All components underneath the car were stripped from the car, renewed via bead blasting and then powder coating or replaced with OE replacements and then reinstalled with fresh rubber and grease. This includes the self leveling struts and wheel bearings. Timing and valves were also corrected.

Really recommend the Auto-Rx treatment. In terms of bang for the buck, that made the biggest difference to engine compression and performance. Completely eliminated any blowby as well.

If you can afford them, the 14" aluminum steelies are an incredible modification, reducing upwards of 42lbs of unsprung weight. It's like taking 200lbs of sprung weight out of the car.

Bengoshi2000 · #**167** 08-29-2019, 06:21 AM

My '91 300D (125k miles) has gotten as high as 38 (non stop highway trip running 70 mph) and as low as 23 (right after I bought it, before i ran a couple tanks of b99 through it and changed both fuel filters).

My previous job involved a 35 mile "country roads" commute, it averaged 32 mpg. My new job is only 2.8 miles, so it's dropped to the upper 20's.

t walgamuth · #**168** 08-30-2019, 07:15 AM

Quote:

Originally Posted by barry12345

If traffic is heavy and fast. There is a small risk to slower than the general flow. Usually I time trips if possible so I just can comforatably float along and just do the speed limit.

If traffic is really thin I will drop back to 60 mph. Oddly enough my wife does the same pretty much. I noticed it seemed to extend the life of tire treads to some extent although there is no way to be sure. Just an insignifigant observation.

We both are also in our seventies and speeding tickets or other infractions would attract attention perhaps. We renew our drivers licenses every five years. When I was 70 I got a lot of questions asked. At 75 none when I was expecting worse.

In a few years I will renew my license again at 80 hopefully. I will also give it up the day I feel incompetent. Also your doctor is required to turn you in. No tickets cannot hurt. I have no wish to hurt anyone either. I have seen the results of people that should no longer have a license when older.

You are never too old for some things I suppose. I was going in and out of the most expensive condo frequently in a city not long ago. Lots of local things to see as it was the first city in Canada. Historical in content. I noticed the same women across the street in a group several times. I went to a local bar and just guess the woman that also entered and sat down beside me. The place was pretty empty.

She was not a hooker. Mining must have been pretty thin for that gold digger though I thought. Around forty to forty five I suspected Desperate perhaps as well. Well structured and dressed though.. At my age they are all younger.

I did cover her bar tab as the conversation was interesting. Had I not been married and somewhat younger say by a month or two. A ride would not have upset me.

Guess who shows up at the condo later? It turns out she was a friend of the really expensive condo owners. She had to be playing with me at the bar. Turns out she was a senior executive at a communication company. They had told her previously that I would be visiting with the wife.

As she came in the condo and we were introduced. I mentioned that we had met earlier.. With women it usually will get mentioned anyways. The wife figured it had to be that day. So she asked did you borrow my husband? She responded she had and he was a gentleman. To following peals of laughter of both of them. Her and the wife got along well for the remainder of the evening. At my expense I suspect.

To be 77 and married is not the best thing to be at times I suppose. She made me understand why some old guys get really foolish . I always had the best at home without a doubt though in many ways.

On occasion now, at 70, I will see a younger woman looking at me in a way that I am tempted to believe is admiring. At that time I recite the old saying "There's no fool like an old fool".

t walgamuth · #**169** 08-30-2019, 07:25 AM

Quote:

Originally Posted by Screwdriva

My post was in US gallons. Keeping a W115/ W123 diesel well maintained can yield improvements over the norm that exists today.

I've had at least 20 123 diesels. In my experience the only way to achieve such mileage figures as you have posted was in my 240d us spec car with the following modifications:
Freshened engine including injectors. 300d euro spec na motor. 307 diff. five speed od transmission running 55 to 60. With that combination we topped 40mpg highway a few times.

I don't see how it would be possible with stock gearing and an automatic. I would suspect a slipping odo or some other measuring inaccuracy. Hyper miling might do it or running about 40 mph highway.

funola · #**170** 08-30-2019, 10:33 AM

Quote:

Originally Posted by barry12345

This above post in all probability is on the imperial gallon. The old jetta diesel I drove last week on a trip. Tends to average 54 miles per imperial gallon after several tankful checks. About 15 percent city and 85 percent highway. That is also with the air conditioning running most of the time.

So the old Jetta is giving about 44-45 miles per American gallon. Possibly putting it at the top of easily available fuel efficient cars. That is the feel good component of a car that will chew up enough repair costs down the road. To just make it an average at best cost per mile over the road.

I think that's about right for the Jetta. I love my 92 with a turbo and a 5 spd AVX. I can't calculate actual MPG since it runs on a 3 tank veg system. I think the last time I checked I was getting at least 250 miles per diesel gallon.

About 2 months ago, the IP started spewing fuel on the bottom towards the block. Inspection mirror revealed it was leaking at the distributor head o-ring. I was able to replace the o-ring w/o removing the IP, which took 3 hours instead of much more.

Screwdriva · #**171** 08-30-2019, 02:55 PM

Quote:

Originally Posted by t walgamuth

I've had at least 20 123 diesels.
Freshened engine including injectors. 300d euro spec na motor. 307 diff. five speed od transmission running 55 to 60. With that combination we topped 40mpg highway a few times.

I don't see how it would be possible with stock gearing and an automatic. I would suspect a slipping odo or some other measuring inaccuracy. Hyper miling might do it or running about 40 mph highway.

This is a Euro spec 300D NA motor with a fully freshened engine and mechanicals. I typically drive at 55-65 mph. I've never been able to exceed 36-37 mpg US highway. As shared earlier, this drops to 23mpg in London city conditions

t walgamuth · #**172** 08-30-2019, 03:39 PM

Quote:

Originally Posted by Screwdriva

This is a Euro spec 300D NA motor with a fully freshened engine and mechanicals. I typically drive at 55-65 mph. I've never been able to exceed 36-37 mpg US highway. As shared earlier, this drops to 23mpg in London city conditions

What is the formula you are using to convert back to us gallons?

okyoureabeast · #**173** 08-31-2019, 05:32 PM

Quote:

Originally Posted by t walgamuth

I've had at least 20 123 diesels. In my experience the only way to achieve such mileage figures as you have posted was in my 240d us spec car with the following modifications:
Freshened engine including injectors. 300d euro spec na motor. 307 diff. five speed od transmission running 55 to 60. With that combination we topped 40mpg highway a few times.

I don't see how it would be possible with stock gearing and an automatic. I would suspect a slipping odo or some other measuring inaccuracy. Hyper miling might do it or running about 40 mph highway.

I'm like you. 25.6mpg was my maximum going 73 in a 300d. I'm skeptical of all claims of anyone achieving more with an om617 either turbo or na.

I'll have to see it to believe it. Until then, this is how I feel:

Which is ironic because they just came out with a new album!

Screwdriva · #**174** 09-01-2019, 11:00 AM

I don't convert anything myself. I enter the miles driven and liters filled into my fuel economy app which does the conversion when I specify US gallons on it.

I'm obsessive about tracking my mileage and economy because a deviation from this could indicate that something is wrong, as had been prior to restoration. Skepticism or not, currently all is good in my engine bay (attached)

I am in the process of renewing my W115 240D, detailed on this thread. To date, best I can do is 30 mpg US highway, despite being a 4 spd manual and an OM616. Feel free to follow along as I try to get it to match or beat its younger sibling.

t walgamuth · #**175** 09-01-2019, 12:55 PM

If you'd like us to check and verify you could provide the raw data and we can check it manually.

t walgamuth · #**176** 09-01-2019, 12:55 PM

30 is good for a 240 stick.

Screwdriva · #**177** 09-02-2019, 11:09 AM

Quote:

Originally Posted by t walgamuth

30 is good for a 240 stick.

Good to know!

Since that measurement I've replaced the front wheel bearings and factory grease (had become lard like), the seized calipers, factory steel wheels with 14X5.5. aluminum steelies, and the budget 185/70 R14 rubber with Continental EcoContact 6 low rolling resistance 175/80 R14 tires. I've also done a diesel purge and replaced the leaking fuel injector return hoses.

I'm sure this will cumulatively help increase the economy significantly. Will report back when I have a measurement!

BlueGermanTank · #**178** 05-30-2023, 11:44 AM

Bringing this back up. I never believed the people saying 30+ MPG on the W123s. Got 31.4 MPG on my 1985 300D Turbo saloon with freshly changed Rotella T6 5W40, new tires, and a recent tune up. Also probably helped I was driving on a county highway with a speed limit of 60 mph, maybe 25% city driving. This engine still sputters a bit on startup (valve stem seals?), and is by no means perfect. But just replacing the 15W40 dino with 5W40 synthetic was enough.

WWhitmore · #**179** 05-30-2023, 01:19 PM

My 1985 300D (federal version) averages 30 mpg.

ROLLGUY · #**180** 05-30-2023, 06:38 PM

Quote:

Originally Posted by BlueGermanTank

............But just replacing the 15W40 dino with 5W40 synthetic was enough.

Is that 5W40 Diesel rated??