Oh dear

[Dieselman]

So be fair, if MPG is your primary concern, a V6 diesel (of any make) is probably not the right choice.

I just find it poor that the same size engine as mine is so much less efficient now, it should be better.

 

[@MARK]

I just find it poor that the same size engine as mine is so much less efficient now, it should be better.

I have no idea if it is or it isn't

It's not yet run in and after just 500 miles of cross country driving it's impossible to draw any conclusion.

Look at my signature in a few weeks (I get through about a tank per week) and lets see what the numbers say.

 

[trapperjohn]

Lets not forget Dieselman has taken a stock engine and done to it only what Dieselman can. Radiator blinds in the winter, heating devices, best knowledge of tyres and probably driving techniques in total sympathy with a drive train he knows intimately which is totally worn in.
I take my hat off to you DM and just wonder what you could do with a new C350 CDI once you had it fettled to your liking? Bit of a challenge for you there.

BTW way had my 124 300D 24V decated on Thursday. Sounds great but MPG appears to be suffering. Probably because I drive most places with the window down and plant my foot to the floor to listen to it howl.

 

[Dieselman]

Lets not forget Dieselman has taken a stock engine and done to it only what Dieselman can. Radiator blinds in the winter, heating devices, best knowledge of tyres and probably driving techniques in total sympathy with a drive train he knows intimately which is totally worn in.
I take my hat off to you DM and just wonder what you could do with a new C350 CDI once you had it fettled to your liking? Bit of a challenge for you there.

BTW way had my 124 300D 24V decated on Thursday. Sounds great but MPG appears to be suffering. Probably because I drive most places with the window down and plant my foot to the floor to listen to it howl.

Without any work my car would achieve better than those figures on such driving and my car is noticeably under-geared.
Cross country driving generally flatters diesel engines as it uses mid range torque.
Of my recent tanks the latest one is the worst, but the driving the fastest.

For your car, reducing exhaust back-pressure should normally assist engine efficiency.

I'm really quite disappointed with the figures I see for the new CDi engines.

 

[st4]

Crickey, that mpg is shockingly bad for such driving. It's what's been putting me of getting a 350Cdi, being worse than the old sludge-burner.

The "older" 320cdi is rather good. I've seen 52mpg from mine and average 38-40mpg on most journeys. On a "tour" it might be nearer 36mpg but thats giving it some welly in bits.

A facelifted 211 (without SBC) would serve you really well, and its not DPF equipped. Even a 220cdi output wise matches your car (facelifted are 170bhp)

The 350's are substantially more power than my car, and a drop of 10% in efficiency is probably a sacrifice I would not mind making. For you, you'd see such a massive increase in performance from your 300 I dare say you wouldn't mind either.

However, reading on an electrical component failure on what is a split new car does concern me. It just should not happen.

 

[Dieselman]

The 350's are substantially more power than my car, and a drop of 10% in efficiency is probably a sacrifice I would not mind making. For you, you'd see such a massive increase in performance from your 300 I dare say you wouldn't mind either.

However, reading on an electrical component failure on what is a split new car does concern me. It just should not happen.

Reliability is a concern too. Why go from possibly the most reliable car Mercedes ever made to one of the less reliable ones and lose economy as well.

As far as power and economy go, I wouldn't think @Mark is driving any quicker than me and he isn't achieving the same MPG in a smaller car.

It's all these things have made me keep the crate so long.

 

[st4]

Reliability is a concern too. Why go from possibly the most reliable car Mercedes ever made to one of the less reliable ones and lose economy as well.

And spend £30k in the process.

For you, as it is a nice example of the 210, there really is not much point in changing cars, you won't end up with something 10x as good.

However if you wanted to, common rail will be facing you pretty much everywhere you go if you want a large diesel saloon car.

They do accelerate quicker the newer ones, whether or not that's something you would use is up to you. On the times I don't use the power, the car will easily do 40mpg + and I've cruised at the speed limits from Helensburgh into the lake district and seen 45mpg.

If the additional performance of the V6 and marginally additional fuel consumption a put off (and I don't blame you, I don't like mentally having to price journeys/trips in the car) the 220cdi in the later 211 would give you a good turn of speed and decent economy. However, I thrashed mine back from work and was doing the same speed (in the DCW) we did down at Ollies in 2009, it returned a horrific 29mpg. I wanted to clear her out.

The later 4 pots I think you are right, they will be a nightmare (the two turbo set ups in the BE cars). Whats weirder about them is some owners are getting really great returns on those cars, others are getting really bad returns. Is it that some engines are good, or some drivers as are gentler....

As far as power and economy go, I wouldn't think @Mark is driving any quicker than me and he isn't achieving the same MPG in a smaller car.

It's all these things have made me keep the crate so long.

No, but is his car any more aerodynamic than yours, remember, its a wagon as well, they are never as good on fuel.

Over a long run (he uses that fuelly thing) we can see what sort of MPG he returns in the car but its hampered with EGR, DPF's and a tight engine that your car is not.

 

[Dieselman]

They do accelerate quicker the newer ones, whether or not that's something you would use is up to you.

I would as I like acceleration, it's fun.

If the additional performance of the V6 and marginally additional fuel consumption a put off (and I don't blame you, I don't like mentally having to price journeys/trips in the car)

It's not the actual cost, it's more the thought of going backwards when we should be going forwards that seem illogical.

I'm genuinely interested in the real world economy figures for these cars as the 350 is supposed to be more economical than the 320.

 

[st4]

I would as I like acceleration, it's fun.

You'll love the 350cdi, its much gruntier than the 320cdi. I've driven both, CLS350cdi and "the shed"....

It's not the actual cost, it's more the thought of going backwards when we should be going forwards that seem illogical.

I'm genuinely interested in the real world economy figures for these cars as the 350 is supposed to be more economical than the 320.

In a way we are. In terms of performance the 350cdi is now as powerful as a 430 V8 in a 210, with a brabus box now more powerful than the 5000cc 500 V8. Both of these do mid 20's to the gallon, maybe 30mpg. The diesel will do 10mpg more in every situation and be as fast as the range topper from two model series ago....

Lower down the diesel scale, you have 220cdi and 250cdi cars that do (and we do have owners to back this up) MPG well in excess of 50mpg and deliver more power than the 3 litre model from two ranges back.

Cost wise, your car new cost the same as a new E350cdi. Factor in 10 years of inflation then your car would cost about £15k more in todays money. Then consider the higher safety levels, the better road holding, equipment, relative lack of body corrosion (its a Mercedes, corrosion is a relative term) and you can see how the cars have moved on from 210, to 211 (210 to 211 isn't a massive jump as the basic car goes) to 212 (211 to 212 is a big jump, in road holding, comfort, interior, refinement).

If you're really interested, you need to do a proper experiment. Comparing other peoples MPG with yours is needless, they will drive differently. To search out the real truth, you should hire an E350cdi, an E250cdi etc and drive them on a route you know and see what they do in your hands. I always read in horror of low MPG in 320cdi V6s that some owners post on here, I never see it, most of the time I drive like miss daisy

 

[Oli]

Reading about diesel owners MPG depresses me. I'm really starting to miss my old IDI Peugeot which managed high 40s and ran on cooking oil.

 

[Cabe]

Aaaand its post like that ***, that keep putting me back on the Merc website looking for a new toy

 

[Adam230K]

Diesels are so much more effecient than petrols but what people are forgetting is when you start to pour some serious horsepower into a diesel engine it still needs to drink enough fuel to give you the performance you're asking for. The diesel 300bhp BMW S6's are a great example of this, the average very close to what a relaxed petrol V8 will average (3-4mpg better, but not much in it) if its driven properly.

Also.. a faulty camshaft sensor will cause the OP's engine to drink more than normal... lets see what he gets in his next tank.

Considering I put £60 diesel in my polo and get 550-600 miles, I think it isn't bad he's getting 550 miles out of (£80?) and it has 260bhp whereas mine has 120-odd bhp less with alot less weight to haul around too!

 

[@MARK]

As others have said, I wouldn't take too much notice of the Fuelly number in my signature until I have got to at least 6 or 7 fill ups.

 

[Dieselman]

Diesels are so much more effecient than petrols but what people are forgetting is when you start to pour some serious horsepower into a diesel engine it still needs to drink enough fuel to give you the performance you're asking for.

But on the road, you are only using 25% of the maximum power in any reasonable performance car, so why do they now use so much fuel?

 

[LTD]

But on the road, you are only using 25% of the maximum power in any reasonable performance car, so why do they now use so much fuel?

To produce all that lovely soot that needs to be filtered out ???

 

[st13phil]

I'm genuinely interested in the real world economy figures for these cars as the 350 is supposed to be more economical than the 320.

FWIW, my pre-BlueEfficiency W204 C220CDI averaged 42.0 mpg over almost 42,500 miles, with a best of 46.2mpg over a tank and a worst of 34.7mpg. Over its first 4,800 miles my W212 E350CDI has averaged 39.0mpg with a best of 42.9mpg over a tank and a worst of 37.1mpg. This is in like-for-like driving, although proportionally there haven't been that many long motorway runs in the W212 yet which I know will improve the average. I think one of the issues with the 350CDI engine as far as economy goes is that the mid-range performance is so good I find myself using it purely for the enjoyment factor. If I didn't use the performance that it provides I'd expect it to better the economy of my W204, which is pretty impressive considering the increased frontal area and weight of the W212.

One thing that does puzzle me is that the trip computer mpg figures for the W204 were rarely more than 2 or 3% adrift of the tank-to-tank calculated mpg (cumulatively over 42,420 miles it was just under 1.3% optimistic), whereas on the W212 it's all over the place, ranging from around 7% optimistic to almost 14% optimistic with a cumulative error over 4,828 miles of 9.6%. And before anyone asks, it doesn't have a fuel leak and no-one's siphoning it out, either

So what mpg do you get from your W210, Will?

 

[Dieselman]

Last tank was only 36 but that included a fair bit of high speed work and some heavy acceleration, typically it's about 39-40mpg without trying.

Is yours the 231bhp or the 265 bhp version of 350. The later 263 bhp version is meant to be more fuel efficient.
What bothers me is that the reported mpg doesn't meet the claimed figures, whereas mine does, so is about the same, or better.

 

[tasn1]

Take it back and swap it for a C63...

 

[st13phil]

It's the latest 265hp version.

From what I understand, the 7G-Tronic Plus 'box (which my car has) is responsible for a significant proportion of the improved economy over the 231hp version, partly due to reduced transmission losses but also due to improvements in the shifting program. The car defaults to the "E" (Economy) mode for the gearbox at startup and in normal driving the upshift points only occur much above 2,000rpm if you're pressing on.

BTW, one other data point: I always have the aircon on so that will hit fuel economy a bit. Quite how much, I don't know.

 

[Mactech]

I know that sometimes the mpg of current cars can seem slightly disappointing compared to the older diesels. But fuel consumption is not the only parameter the manufacturers are under pressure to improve.
Read these figures carefully and you will see that today’s E Estate is massively cleaner in most measured values than 11 years ago. Yes the headline CO2 is down, but look at the other figures.
Like 28 times less particle emissions!

Note that the figures are the values under the Euro standard 5/6

2001 E320 CDI Estate CO2 209 Euro Standard 3
CO Emissions [g/km or mg/km under Euro 5/6] 0.273
NOx Emissions [g/km or mg/km under Euro 5/6] 0.000
HC+NOx Emissions[g/km or mg/km under Euro 5/6] 0.400
Emissions Particles [g/km or mg/km under Euro 5/6] 0.036


2012 E350CDI Estate CO2 170 Euro Standard 5
CO Emissions [g/km or mg/km under Euro 5/6] 258.0
NOx Emissions [g/km or mg/km under Euro 5/6] 148.0
HC+NOx Emissions[g/km or mg/km under Euro 5/6] 185.0
Emissions Particles [g/km or mg/km under Euro 5/6] 1.0

We all want more economical cars but nobody is about to prove Newton wrong just yet Nice clean air to breathe is kind of important too!