Mercedes E350 BlueTec Diesel - 38 MPG in Real Life Driving

Yikes! Starts at $52K in the US. Too rich for my blood.

 

The 37.83mpg is highway driving. Hardly a great achievement for a diesel but for a heavy car like the merc, not bad. In town, it is going to suffer big time. It isn't easy to propel a beast from a stop.

 

You're kidding right? I'd say that was a fantastic mpg for a car that size. Not a diesel fan myself other than when they're in SUV's or bigger cars like the E class where they'll spend most time on the highway.

I wonder what the petrol version would get on this same run? I'd say if you do lots of highway miles a diesel would be the car for you. Just don't drive it in the city

 

Diesels are made for the highway, they drove it on a highway. It is the same gag others use. The petrol cruze eco can get 40-ish mpg if driven at 55mph on a highway without stopping. The general public then thinks that all cruze trim models will get 40-ish mpg no matter how and where they drive. Most are too stupid or lazy to actually calculate their mpg and just assume they are getting 40.

So the E-Class has a model that gets 37.6mpg in a straight line down the highway. Now they can claim the 37mpg number in fuel adverts and sell more of the non-blue ones.

 

lol but a Cruze (Euro Astra) is a small car. The E350 is a mid range Mercedes. For its size 37 mpg US is pretty amazing. If you travel long distances on the highway and are usually in the market for a luxury car then the diesel Merc is a good buy.

Don't dismiss it just because it's a diesel. Now if it were a diesel just for town/city use then I would be much less enthusiastic.

 

I wasn't comparing it to a cruze, I was comparing the idiocity of the highway stunt. Give that to anyone who doesn't have a 100% highway commute and the mileage will be much worse.

37mpg on the highway with diesel for a boat of a car isn't bad. But it isn't news either. Hey look the sun rose again!

 

Well we agree to disagree

38 mpg (US) in a big car isn't news in Europe but I'd have said it was in the US. I can't imagine many other cars of similar size and performance sold in the US that can match that.

 

I just checked at Fuel Economy and the 2012 camry hybrid is 6 cubic ft bigger and gets 39mpg.

 

hmmm onto a loser with this one aren't I? lol

I guess there's nothing in the same league as the E350 with similar economy as a Toyota certainly isn't. Other than hybrids there is nothing similar.

Being a hybrid owner I see first hand the superior economy they give to diesels but equally I think in certain circumstances diesels can be useful - such as big cars like Mercs and also SUV's - the Range Rover V8 diesel is a good one.

I am not a fan of diesel use in cities due to pollution (and noise) concerns and they're not as economical as a hybrid. But if you do long distance travel then they're great - millions of trains can't be wrong eh?

 

I bet I could get 35 mpg hwy in a gas powered honda accord which gallon for gallon (or more correctly joule for joule) would be around 38 mpg hwy diesel. yes/no?

 

Anything you do to improve your economy in the Accord, will improve the economy in that Merc. If you can control yourself, you can beat 30mpg in a Corvette, rated 25, on the highway.

Having more energy per gallon doesn't negate the fact diesel engines are more thermally efficient than a comparable gasoline one. Bringing it up also opens a can of worms. With heavy crude, the naturally occurring diesel needs to be cracked to get the percentage of gasoline we want. Shouldn't the energy used for that be factored into the comparison. Premium gasoline contains less energy than regular. The Volt's numbers should be raised to reflect that.

 

The Accord is already rated 34 mpg gasoline by EPA, so by energy content it is equivalent to 37 mpg diesel, or about the same as this E350.

You have to normalize the units somehow. That's why MPGe was created for EVs. If we compare gas to diesel, this is a far comparison. Diesel does have more energy, and supposedly has a higher thermal efficiency. If that is that case, an E350 getting 38 mpg diesel down the highway is not surprising.

 

Thanks Tideland - I take back all those things I've said about you

Why would someone who can afford an E class Merc want a diesel? Well plenty sell in Europe and despite our higher fuel costs the same argument applies - if you can afford a £60,000 car you can afford £6 a (US) gallon.

The answer I guess is why shouldn't you get a diesel? It gets better economy on the longer runs and thus needs filling less often. Also, just because you have money why should you waste it on fuel for your car? I have plenty of rich customers and they grumble about the high cost of fuel over here, despite living in a £3m house etc.

I also don't think many on this forum will have driven a modern diesel Merc and probably remember the diesel Mercs from the early 1980's. Well the comparison between that is the same as comparing any car from today with the equivalent from 1980! Things have moved on - a lot.

 

Is the vehicle in question a US spec car or a Euro spec? Just you said it had a few thousand km on it and drove it through Holland.

If it's a Euro spec then wouldn't the mpg displayed be UK gallons and not US? Would they reprogram the system for US gallons for US spec vehicles?

It works the other way too - I had a Ford Cougar which was an official Ford UK conversion from LHD US Mercury spec to RHD UK spec. Thing was I could never get it over 33 mpg but it eventually turned out the computer was calculation US gallons.

 

It would be Euro spec. They referred to the vehicle being driven in the EU. Companies can, I believe, get permission to run EU spec vehicles in the USA for demonstration purposes.

However, even if it's EU spec, a new car should be Euro 6, and as long as they don't lumber the US version with more weight for safety, the final US version shouldn't have different mileage because MB uses SCR for the NOx control and that's the only target where Euro 6 is looser than Tier 2 Bin 5.

The mpg is US: they quoted the l/100km figure.

A solid highway run like that should return good numbers. Steady PSL driving at 65 and then some <= 55 would be easy for the car. As much as it would be nice for the USA to be full of compact and mid-size hybrids, I'd really like to see some good diesel engines in larger vehicles (and not just pick-ups).where the benefit would really be felt most. They'd still guzzle, just not as much.

Oh and the point somebody made above about lower refining energy is true, but not as true as it was since extra processing is required for ULSD.

 

BTUs per mile would be the most transparent. Since the energy content of gasoline varies between octanes, brands, and seasons, it would be best to go by the EPA's test formula when using EPA numbers. Miles per kilogram might actually be easier since the energy content per mass is really close for the petro fuels.

That's EPA and article is these authors' results. This Bluetec is available and is rated 21 city/32 highway. To keep it comparable, we should look at the V6 Accord, it's 20/30. The Accord will come out ahead if energy content is considered, but fuel economy isn't likely a top priority to a Mercedes shopper or even someone looking at a V6 Accord. The diesel produces 157% of the gasser's torque at half the rpm. With some spirited driving in the real world, the economy gap will climb between the two cars has the Mercedes requires less pedal for the same results.

A hypothetical to consider is what would the authors have gotten with a 4 cylinder diesel Accord that Honda once considered bringing over?