are merc cdi's known for 'bad' mpg

[Rory]

A roundabout should be a chance to save fuel, as you are going slower, not burn it. At 70mph you are simply going to fast for it to be very economical, too much areodynamic resistance.

I just straight-line roundabouts now.

Of course at lower speeds the gearbox doesn't fully lock-up, so you're losing some efficiency there. I think that's why we get some peope who swear their cars are more economical at 80 than 70.

I agree with gIzzE though - some of the figures people show snaps of are...remarkable. I won a contest for smooth driving and I've tried ultrasmooth driving, quick accelleration to cruising, and hyper-mile techniques and I can't get the high 50's and 60+MPG numbers that some people post up.

I can get low 50's, but it takes a 100 mile+steady speed run to get there. On open, flowing A roads, I can't get above mid-40's and any run of less than 20 miles and I'll struggle to get 40 - the car seems to start off displaying 33 and it's very slow to creep up.

I seem to get to a point where a downhill run or slowing down on the over-run will add .1MPG but picking up speed again takes .2 off!

 

[John]

I'm not so sure onboard computers are always accurate though.

I think you'd need to calculate manually to be sure they are.

I've heard more than one case recently where the computer reports one thing but the reality is different when worked out from scratch...

 

[x332race]

C270 Estate on a run to Cambridge the other day.....A41, M25, M11 taking it steady but not slow. Have found slightly increasing tyre pressure makes a big difference. Calculations show that the computer over reads mpg by about 10% though so actually probably nearer 55mpg. Computer showing average of 40mpg over last 10,000 miles (includes some towing)

 

[A210AMG]

^ thats great


The C180K estate auto I had the other day I really couldn't understand it? 34 mpg was the best I could get, ok its a petrol but I was driving like I had glass un secured on th roof !!!

Jump in my E320CDi and 34mpg is instant

 

[Adam230K]

The kompressor engines dont get good mpg if you drive it like a daisy, but when i drove it like I stole it (which was all the time in my poor car 230K) it still returned 28mpg average.

 

[rf065]

I'm not so sure onboard computers are always accurate though.

I think you'd need to calculate manually to be sure they are.

I've heard more than one case recently where the computer reports one thing but the reality is different when worked out from scratch...

I can vouch for that, on long runs at motorway speeds, my computer will say around 42 or 43mpg, measuring brim to brim will always give a figure of at least 44 or 45mpg.

Russ

 

[renault12ts]

when i say bad mpg i mean in a diesel contex.!!

i have a clk220 cdi sport 2006 and my computer never registers above 40mpg.. even on a long run.

im guessing its to do with the automatic gear box.. sometimes its "stupid" it sometimes i look down at the rpm and its blatently holding onto 4th gear when it can easily be in 5th

my previous car (audi) was far better on fuel and was a 2.0 tdi.. probs the 6 gear manual was the reason.

will remaping help? i sometimes feel i might has well gone for a v6 petrol and had extra fun!

Why would you start a thread and not wait around for the answer? Time wasting?

 

[snoop51]

I just straight-line roundabouts now.

So your one of those are you? You ever thought about the poor sod coming up the outside to turn right? Lanes are there for a reason including on roundabouts.

 

[rf065]

So your one of those are you? You ever thought about the poor sod coming up the outside to turn right? Lanes are there for a reason including on roundabouts.

I'm sure he checks his mirrors first.

Interestingly, on my recent trip from Spain through France and back to the UK, it appears that the outside lane on a roundabout is the only one to use regardless of which turn off you are taking!

Russ

 

[st4]

I'm sure he checks his mirrors first.

I sure hope so otherwise he'll be collecting other cars paint, given that Rory hasn't asked re good bodyshops from memories makes me think he has got this off to a fine art.

Cutting roundabouts and straight lining bends, etc is good driving. Its less wear on the tyres, brakes, offers you more visibility etc. So long as it does not upset someone else then you should be doing it.

I try and take 2 lane roundabouts at 30-40mph where I can, maybe a bit more if its clear. Its also a lot of fun!!!

Interestingly, on my recent trip from Spain through France and back to the UK, it appears that the outside lane on a roundabout is the only one to use regardless of which turn off you are taking!

Russ

I noticed this in France, I reckon they drive well over there, but its maybe not in their rules and regs re what lane to be in and you just treat the roundabout as a 1 lane job.

 

[recardo]

when i say bad mpg i mean in a diesel contex.!!

i have a clk220 cdi sport 2006 and my computer never registers above 40mpg.. even on a long run.

im guessing its to do with the automatic gear box.. sometimes its "stupid" it sometimes i look down at the rpm and its blatently holding onto 4th gear when it can easily be in 5th

my previous car (audi) was far better on fuel and was a 2.0 tdi.. probs the 6 gear manual was the reason.

will remaping help? i sometimes feel i might has well gone for a v6 petrol and had extra fun!

I'm in the same boat with a 2005 C200 CDi, getting 30mpg
was expecting high 30's around town and mid 40's on a long run.
been driving like miss daisy to get maximum mpg but really dissapointed to the extent of not using the thing unless I really need to.
So far local indy has done STAR diags, engine & gbox oil changes, new thermostat, checked all pipes (intercooler etc) and nothing obvious...
I guess the MAF is the next expensive item to be replaced in the vague hope it does something.....

 

[Ian B Walker]

Having just re built a 270cdi engine we find that on the motorway at 75mph with the limiter and cruise set we get 55mpg. :bannana::bannana:

 

[Dieselman]

Having just re built a 270cdi engine we find that on the motorway at 75mph with the limiter and cruise set we get 55mpg. :bannana::bannana:

The 270 Cdi is the most efficient Cdi, a great compromise between power and economy.

 

[Deleted member 37751]

The 270 Cdi is the most efficient Cdi, a great compromise between power and economy.

I had a W211 E270 CDi as my first Mercedes and like you say, it is the best compromise.
I'd go as to far as to say that it is also one of the most durable engines ever made, it's the same 5 Cyl they put in the 312 Sprinter and these are well known to do 500k without much bother.

 

[Adam230K]

Hold on, you can't compare the steptronic 'box in your 540i with the latest 8 speed 'boxes on current BMWs, that 'box came out in 1994 with the 740i and is now 17 years old, there have been 4 more generations since then and they are now seriously good.

Don't get me wrong, I don't think the Merc 7g is bad at all, and still one of the best out there, but the BMW is actually smoother and more efficient, but it has only been out a very short time, and I am sure that Mercedes will trump them again very shortly if not with a new gearbox with newer more improved software.

I thought the gearboxes in 94 bmw's, like the 740i were the same ones that were in GM cars like vauxhall, then they changed a bit later to the ZF ones (5HP24's?)? And I was comparing the 5speed on my 540i with the c200's 5speed, they had similar build dates and they were miles apart in feel.

In either case, the next generation 6speed AT that I drove in the 545i I had for a while was just as stupid as the 540i, the steptronic does work nice I have to admit and its very quick but in auto mode its just not the best, especially when coming to a stop you can just feel it changing down in such a clumsy manner.

just my opinion anyway

 

[gIzzE]

The tourque converter will lock up at anything over 10mph and 1000rpm on a BMW which can give you the snaps round town as it starts to lock up and then has to unlock quickly and change back down.
This seems to have gone from the latest 8 speed boxes, and for the better.

It is well worth people trying an 8 speed box on a new 5 series or similar as they are pretty impressive.

 

[Adam230K]

The tourque converter will lock up at anything over 10mph and 1000rpm on a BMW which can give you the snaps round town as it starts to lock up and then has to unlock quickly and change back down.
This seems to have gone from the latest 8 speed boxes, and for the better.

It is well worth people trying an 8 speed box on a new 5 series or similar as they are pretty impressive.

I think a test drive in the new 5 is on the cards...

I prefer the new looks so much more to the one it proceeded

 

[andylinney]

Here's yesterday's run into Glasgow city centre from Irvine on the west coast so a nice mix of A Roads, B Roads, Motorway and City driving with a quite respectable 50+mpg.

 

[gIzzE]

I think a test drive in the new 5 is on the cards...

I prefer the new looks so much more to the one it proceeded

It is a great car, I have done quite a few miles in a 60 plate 520d SE touring auto now, and pretty much all good.
The ride is much more compliant now and feels more Merc than BMW, in SE guise on 17s anyway, and the W212 now feels sharper as well, spec a W212 is sport and compare the 5 series in SE and the gap is well and truly closed.

Overally I love the new 5 series, the gadgets are excellent, the interior is as good as anything I have seen and the looks of it are very smart if a little bit subtle compared to the outgoing one, but I do think that as a daily driver I would still go for another E Class.

If I were looking at an E500 vs a 550i I would get the BMW, but as a 520d vs E250cdi I would definitely go E class, and even with a 530d vs E350cdi I would still go E Class.
But, buying nearly new you can get an E350cdi estate with comand for the same sort of money as a 520d se touring with Media, so it would have to be the E class, the 530d is around £5-10k more.

 

[Dieselman]

The ride is much more compliant now and feels more Merc than BMW, in SE guise on 17s anyway, and the W212 now feels sharper as well, spec a W212 is sport and compare the 5 series in SE and the gap is well and truly closed.

Not much of a recommendation, most people say the E Sport is too harsh.