television
Hardcore MB Enthusiast
That chart to me reads as 50mph is the best usable figure
fabes
MB Enthusiast
Nobody's mentioned keeping the tyres inflated at the proper pressure
Not the Merc, but in the Zaffy's book, (which i read once) it stated pressures of 34 or so generally, but increase to 38 for Eco travel and max mpg
Not the Merc, but in the Zaffy's book, (which i read once) it stated pressures of 34 or so generally, but increase to 38 for Eco travel and max mpg
glojo
Hardcore MB Enthusiast
I think this makes sense for the most economical driving because once again when we use arbitrary mph or kph, we are talking forensic conditions on a rolling road under very controlled circumstances. The instant we fetch real world scenario's into the question then it is impossible to give a constructive number. I previously talked about going down any type of hill, but the same will apply at the slightest uphill gradient, should we try to keep to a set speed for the most economical means, or should we try to keep off the boost and ignore the speedometer? Folks that live in East Anglia might not have hills
As an instructor I was frequently asked about 'What speed, or gear should I use for bend X?' My answer was always the same and that was it depended on the exact circumstances at the precise time we were in that situation. When motoring on our highways and bye ways there will always be varying issues that we as drivers need to understand and can never give a blanket answer. Some older Mercedes used to have an economy type gauge, that might rule the right foot! Now we have the instant mpg read out
Happy motoring
Regards
John
television
Hardcore MB Enthusiast
The above is true and showed on my V70 that spent its first 15k mile in Herts and the dial showed 25.7mpg and this has never been re set. Here in Dorset doing average runs it never gets past 22mpg and the average is nearer 20 mpg . On the motor way at 60 its goes up to 33mpg and at 70, 23-24 mpg once going to Stansted doinf 50mpg it went up to 40+ mpgI think this makes sense for the most economical driving because once again when we use arbitrary mph or kph, we are talking forensic conditions on a rolling road under very controlled circumstances. The instant we fetch real world scenario's into the question then it is impossible to give a constructive number. I previously talked about going down any type of hill, but the same will apply at the slightest uphill gradient, should we try to keep to a set speed for the most economical means, or should we try to keep off the boost and ignore the speedometer? Folks that live in East Anglia might not have hills
As an instructor I was frequently asked about 'What speed, or gear should I use for bend X?' My answer was always the same and that was it depended on the exact circumstances at the precise time we were in that situation. When motoring on our highways and bye ways there will always be varying issues that we as drivers need to understand and can never give a blanket answer. Some older Mercedes used to have an economy type gauge, that might rule the right foot! Now we have the instant mpg read out
Happy motoring
Regards
John
DITTRICH
MB Enthusiast
Fuel consumption depends on many things...
1 tyres - pressure - under or over
2 engine revs - friction in engine
3 vehicle speed - wind resistance
4 engine characteristics - those chart thingies for torque and bhp
5 power consumers - kompressors - aircon - electricity via alternator
6 road conditions - hills - road surface
I remember dieselman saying that driving in top gear and keeping the revs as low as possible without dropping off the bottom of the torque curve would result in the best economy. In a w202 c230k at 1,500rpm in top gear from memory around 35mph. 70mph on motorway delivers around 35mpg under good conditions. In an E300d at 2,500rpm at around 50mph delivers a maximum 45mpg under good conditions. Sadly, we are all in too much of a rush these days to take advantage of economy.
Les
1 tyres - pressure - under or over
2 engine revs - friction in engine
3 vehicle speed - wind resistance
4 engine characteristics - those chart thingies for torque and bhp
5 power consumers - kompressors - aircon - electricity via alternator
6 road conditions - hills - road surface
I remember dieselman saying that driving in top gear and keeping the revs as low as possible without dropping off the bottom of the torque curve would result in the best economy. In a w202 c230k at 1,500rpm in top gear from memory around 35mph. 70mph on motorway delivers around 35mpg under good conditions. In an E300d at 2,500rpm at around 50mph delivers a maximum 45mpg under good conditions. Sadly, we are all in too much of a rush these days to take advantage of economy.
Les
glojo
Hardcore MB Enthusiast
Who remembers Clarkson going from London to Edinburgh and back on a single tank of diesel. big V8 diesel As Dittrich has suggested every electrical gadget switched off (including cruise control)
John
As Dittrich has suggested every electrical gadget switched off (including cruise control)John
Soltan
Active Member
Who remembers Clarkson going from London to Edinburgh and back on a single tank of diesel. big V8 diesel
John
That was in an Audi A8 wasn't it? As I recall his car was 'hic-uping' on the final few miles when he got stcuk in traffic. He got back on fumes!
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The way the official EU fuel consumption figures (ie Urban cycle, Extra-urban cycle, and Combined) are derived from a specific set of tests in lab conditions to allow for neutral comparision between vehicles.
The key to it though is consistency, as it doesn't really reflect real world driving, and hence it's no surprise that official figures seldom match real world figures.
I say it doesn't reflect the real world because the car isn't actually driven on the road, it literally stays in a lab (test cell), so no gradients, no wind, no aerodynamic drag, no variety of road surfaces, etc.
It's been ten years or so ago, but I have actually performed the tests. Things may have changed in the meantime, but if it has the I doubt it's changed by much.
The tests are performed on a rolling road with the vehicle stationary. A screen is placed beside the driver's window which effectively plots a line graph, which scrolls horizontally, which if I remember right is road speed on the vertical axis and time on the horizontal axis.
A dot is then plotted on the graph showing the road speed of the car through time, and it's the tester's job is to drive the car so it follows the line perfectly. The line goes through a series of climbs, falls and plateaus to simulate a journey, or a cycle. The same cycle is then used for every car.
The fuel is monitored closely and measured and hence a fuel consumption figure is calculated.
The key to it though is consistency, as it doesn't really reflect real world driving, and hence it's no surprise that official figures seldom match real world figures.
I say it doesn't reflect the real world because the car isn't actually driven on the road, it literally stays in a lab (test cell), so no gradients, no wind, no aerodynamic drag, no variety of road surfaces, etc.
It's been ten years or so ago, but I have actually performed the tests. Things may have changed in the meantime, but if it has the I doubt it's changed by much.
The tests are performed on a rolling road with the vehicle stationary. A screen is placed beside the driver's window which effectively plots a line graph, which scrolls horizontally, which if I remember right is road speed on the vertical axis and time on the horizontal axis.
A dot is then plotted on the graph showing the road speed of the car through time, and it's the tester's job is to drive the car so it follows the line perfectly. The line goes through a series of climbs, falls and plateaus to simulate a journey, or a cycle. The same cycle is then used for every car.
The fuel is monitored closely and measured and hence a fuel consumption figure is calculated.
Lots of articulated tractor/trailors and vehicles towing travel at 55mph or a touch more. I know because I sit with them most of the time when towing!!
For vehicles restricted to 60mph on the motorway it's often easier and more relaxing to go with the flow, perfect with cruise control.
It's also a fairly stressful way to drive as you pretty much don't need to overtake, and so a surprising number of cars go in the same flow. If you pass at a higher speed you may not notice, but you'd be surprised.
Yes, it the juggernauts are the problem, I don't want to trail behind them blasting me fumes and dusts. Coaches are faster than me driving at 60mph, then I zoom past them at 80-90mph to get a breath of fresh air in my slk. That fun.
That probably U are by the sea and there heavier air.
Is it standard to have 30psi for the front and 33psi for the rear in Merc cars? When I check the W211 is slightly less for normal and more psi for four persons in the car.
I normally coast down a hill on my manual gearbox but when I tried to do it with my W201 automatic, it clicked and never do it again? Any tips to do it on the auto without damage to the gear box?
I did it once on a hired car in US, it seemed OK.
I did it once on a hired car in US, it seemed OK.
Coasting in neutral is generally recognised as bad practice, and will also damage most auto gearboxes.
Dieselman
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And it's illegal and will probably increase fuel consumption due to the engine running on fuel to idle instead of cutting the fuel on over-run.
Having said that can the fuel be cut on a catylist equipped petrol, used to not be able to do that.
Anyone with an instant read trip computer could tell.
Having said that can the fuel be cut on a catylist equipped petrol, used to not be able to do that.
Anyone with an instant read trip computer could tell.
Yup, the instantaneous MPG went off the scale on my V6 petrol Sharan on the over-run.
television
Hardcore MB Enthusiast
The reason why it is bad practice to coast in N is that the oil is not circulating, in the olden days of the 60,s boxes were fitted with rear pumps, this also enabled you to do a push start. These were deleted in the 70's.
Interesting to read that MB are going to start fitting them again, when and where it did not say
The 722.4-5 must not be confused with the engine breaking of the 722.6 as they are very different in the way that they work
Interesting to read that MB are going to start fitting them again, when and where it did not say
The 722.4-5 must not be confused with the engine breaking of the 722.6 as they are very different in the way that they work
Dieselman
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Oil will still be circulating as the engine is still running, although at idle.
television
Hardcore MB Enthusiast
The highway code states that the car must not be driven out of a gear at all times
