Fuel economy - anyone beating the official figures?

[300bhp/ton]

Limpet said:

The M140i will frequently venture up into the 40s (combined 39.8) on a longer run if you stick to the speed limits.

One example below is at the end of a 155 mile round trip to a client a few weeks back. Busy roads for a few miles to the motorway, quiet-ish motorway, into a busy town centre for the meeting, then back again. Drive selector in default Comfort mode (cannot stand Eco Pro), transmission in normal auto mode, air-con on all the way (it was hot) and just "driving normally".



Staggering for a turbocharged 3 litre petrol auto, IMHO.

Car is averaging 29.4 mpg over 4500 miles (computer says 30.1 so fairly accurate). If I drove it sensibly all the time I reckon I could get the average into the mid 30s, easily. But what would be the point? :P

Edited by Limpet on Thursday 29th June 14:52

Impressive, but if your average speed was 50mph over a 155 mile journey, then you really spent almost no time in towns or traffic. Either that, or you reset the trip for only the motorway work.

[kambites]

Limpet said:

The M140i will frequently venture up into the 40s (combined 39.8) on a longer run if you stick to the speed limits.

Well yes, but "on a longer run" it should be averaging its extra-urban figure which is what, 50mpg?

I don't believe there's many cars out there (with the exception of hybrids which give ridiculous results because of the nature of the test) which wont hit their NEDC combined figure on a long motorway run?

Edited by kambites on Thursday 29th June 15:48

[AMGJocky]

On a run, I'll tickle 30 which is way over what Merc claim.

[Limpet]

300bhp/ton said:

Impressive, but if your average speed was 50mph over a 155 mile journey, then you really spent almost no time in towns or traffic. Either that, or you reset the trip for only the motorway work.

Trip resets overnight (or after being parked for a few hours). It is a geniune door-to-door-to-door figure for the day's business use. Had I reset just for the motorway work, it would be reading upper 40s.

I would say 110 of the 155 miles were on a quiet motorway cruising between 70 and 80 indicated.

Moderate traffic on the way to the motorway (M4 J11 from the A33 in rush hour), down the M4 into Wiltshire, into a customer right in a town centre (not in rush hour, but still stop/start for a couple of miles), and then back again.

Edited by Limpet on Thursday 29th June 16:21

[LayZ]

gizlaroc said:

Targarama said:

Similar to my 2011 CLS 350 petrol. 40.something combined officially. I regularly see 42-43mpg on a long run to London. Helped by a bit of 50mph average speed, but normally cruise is on at 77mph or so and I get 39-41mpg on the same 100 mile journey. Big capacity engines with good motorway gearing always produce better than expected figures if driven the right way

Imho you are daft to buy the big diesel engines, the petrols get within 85-90% of them and so, so, so much nicer.

Best I've ever had out of my W219 CLS 320 CDI is 43mpg on a long run. That did include some 80mph cruise and full bore M6 toll drag race so 45mpg probably easily possible.

[Willy Nilly]

Got my Jazz up to 64.9 on a 90 mile run according to the dash. It was hard work, but interesting to see what it could do. The EU urban cycle figure is 42.2, mine is mostly town bound and I've average 48 on the dash with it for 15,000 miles, which is 45 ish when measuring tank fulls.

[gizlaroc]

kambites said:

Well yes, but "on a longer run" it should be averaging its extra-urban figure which is what, 50mpg?

No. extra urban is starting with a car already up to temperature with warm ambient air temperature then driving for 4.3 miles (7km) accelerating to 75mph and decelerating for half the trip and then slowing down to around 30mph for the rest to achieve an overall average speed of 39mph (63kmph).

So unless you travel everywhere at 39mph it isn't really realistic at all.

This is why we need to bring back a City figure and Motorway figure again. The States use those figures over a long distance and their figures are far more realistic.

Look at the figures for say E250d, US say 26mpg and 34mpg and the UK says 44mpg and 68mpg, or something like that guess which customer is going to be disappointed.

[Glasgowrob]

LOL nowhere near

Ford say

Urban 58.9MPG
Extra Urban 74.3 mpg
Combined 67.3 mpg


ford are a bunch of lying bas'

average MPG over the last 86k miles 44mpg

best I've seen on constant motorway miles 52

Screw you ford and your rubbish Peugeot diesels

[underphil]

some lower volume cars the manufacturers can't be bothered to optimise them for the euro tests

When I had a GT86 I could beat the official extra urban figure if I tried

Same with the Mazda 6 2.5

Other cars I've had recently I'll struggle to get within 15%, some are so far removed from reality it's laughable!!

Another thing to consider is that some people get amazing MPG on the motorway because they tailgate and get a massive reduction in drag as a result

[Frankthered]

gizlaroc said:

kambites said:

Well yes, but "on a longer run" it should be averaging its extra-urban figure which is what, 50mpg?

No. extra urban is starting with a car already up to temperature with warm ambient air temperature then driving for 4.3 miles (7km) accelerating to 75mph and decelerating for half the trip and then slowing down to around 30mph for the rest to achieve an overall average speed of 39mph (63kmph).

So unless you travel everywhere at 39mph it isn't really realistic at all.

This is why we need to bring back a City figure and Motorway figure again. The States use those figures over a long distance and their figures are far more realistic.

Look at the figures for say E250d, US say 26mpg and 34mpg and the UK says 44mpg and 68mpg, or something like that guess which customer is going to be disappointed.

Don't forget that the gallon is smaller in the USA.

[SAS Tom]

Skoda quote 58mpg extra urban for my Fabia. I usually manage around 54-57 on the motorway. I've managed 59.2 on a run from Leeds to Kirkby Lonsdale along the A65 in winter with winter tyres on which I was impressed with. I've also managed 65mpg on the 6 mile commute into the centre of Leeds regularly being over 60mpg.

[300bhp/ton]

Frankthered said:

gizlaroc said:

kambites said:

Well yes, but "on a longer run" it should be averaging its extra-urban figure which is what, 50mpg?

No. extra urban is starting with a car already up to temperature with warm ambient air temperature then driving for 4.3 miles (7km) accelerating to 75mph and decelerating for half the trip and then slowing down to around 30mph for the rest to achieve an overall average speed of 39mph (63kmph).

So unless you travel everywhere at 39mph it isn't really realistic at all.

This is why we need to bring back a City figure and Motorway figure again. The States use those figures over a long distance and their figures are far more realistic.

Look at the figures for say E250d, US say 26mpg and 34mpg and the UK says 44mpg and 68mpg, or something like that guess which customer is going to be disappointed.

Don't forget that the gallon is smaller in the USA.

Yes an important distinction. That said, if you look at the EPA figures for almost any vehicle; city/highway mpg and convert them to imperial gallons. They are generally far more realistic than NEDC and hugely different still.

[HannsG]

I have had over 50mpg in my Panda 100HP

[LordGrover]

underphil said:

some lower volume cars the manufacturers can't be bothered to optimise them for the euro tests

When I had a GT86 I could beat the official extra urban figure if I tried

Blimey! In the 4.1/2 years I had mine I may've made it with two or three tanks when I had a lot of motorway cruising. Otherwise it was typically c. 30 mpg.

[daemon]

datum77 said:

Chedder. Your dad is under a complete misapprehension that putting any car into neutral while going downhill will save fuel. IT WILL NOT!!!!!!
Putting it into neutral means that the engine is ticking over - and therefore using fuel. The ONLY way to save fuel while going downhill is to leave the car in the highest gear and take your foot completely OFF the throttle. The electronics in the vehicle completely cuts off the fuel supply to the engine, thereby using NO fuel whatsoever. As soon as you touch the throttle fuel will again be supplied to the engine.

I would contend that. Over exactly the same distance you're quite possibly right but a car will freewheel an awful lot further when in neutral than it will when in gear. Also any engine design will minimise the fuel requirement whether in gear or in neutral. And surely you're wrong with using absolutely no fuel whatsoever when coasting? Its bound to be still fuelling the engine?

I would be 95% certain that for say a slight declining gradient where someone could coast for say 1/4 of a mile in gear they could freewheel for maybe twice that distance given the right road. No amount of minor fuelling distances is going to offset that.

[daemon]

datum77 said:

The ONLY way to correctly work out fuel consumption on any vehicle is to fill the vehicle with fuel right to the very top and note the mileage. After 300-500 miles, (keep a note of the exact mileage), fill the vehicle in the same way and note how many litre's you've used. Lets say 36.5 litre's. Divide 36.5 by 4.546, (this is how many litre's make a gallon). This will equal 8.191 gallons. Lets say you've done 476 miles. Divide 476 by 8.19. This will give you an MPG figure of 58.11.

The above is the MOST ACCURATE way of working out the fuel consumption of any vehicle, and just like anyone being stupid enough to believe the manufacturers published MPG figures for ANY vehicle - your computer readout should also be treated with the self same scepticism.

Based on real world checking over the years theres probably a 5% inaccuracy in the dashboard reading (most of that checking done in recent VWs BTW).

You're right though that "beating" the official figures on one journey or one stretch of road doesnt mean diddly.

For info, i did beat the manufacturers figures for my 2012 Golf 1.6TI S 105BHP over 30,000 or so miles, recorded via spreadsheet and measure brim to brim each time. The official figure is 62.1MPG and i got around 65MPG on average. I actually got it over 70MPG across an entire fill on a couple of fills.

I'll post a snapshot of the spreadsheet when i can get in to photobucket again.

[LordGrover]

daemon said:

I'll post a snapshot of the spreadsheet when i can get in to photobucket again.

Do you subscribe to PB? Click

[Dr Doofenshmirtz]

I get between 42 and 44 mpg from my MR2 Roadster. Book figures are 38 avg.
The only thing I've done is remove the pre-cat which might help a bit?

[daemon]

LordGrover said:

daemon said:

I'll post a snapshot of the spreadsheet when i can get in to photobucket again.

Do you subscribe to PB? Click

fkers!!

Thanks for that info though. I'll move hosts.

[kambites]

gizlaroc said:

So unless you travel everywhere at 39mph it isn't really realistic at all.

I didn't say it was realistic, I said it was what the figure was meant to represent.

Averaging over the combined figure on a long out-of-town trip is not "beating the official figure", although it does seem to be about the best we can hope to achieve with the current appalling test.