PowerSwitch

Hi there

Do any of you have real-world mpg/kpl figures for new-ish (two-year-old) small-ish cars - Polo/C2 type sized? You can't trust manufacturers' figures.

Just for another whinge, why is fuel consumption listed as litres per 100 km? Is there a reason for it or is it just to stop people thinking about it too much? Why not kpl? We get around 19.5 kpl from our seven-year-old Polo - dead easy to calculate as well as understand.

I think the 'real world' economy of cars depends on many factors:

1. The type of journey.
Commuting in stop start traffic bad. Steady 60mph on motorway good.

2. The style of driving
Obviously avoid speeding, unnecessary acceleration, coast up to the lights, etc.

3. Hilly geography uses more fuel. Heavy loads use more fuel. etc.

4. Keep tyre pressures correct (slightly higher than nominal rating).

Of course you know all this !

So a Prius is good in stop/start traffic, but a medium sized diesel will be just as good for long distance cruising.

I suspect heavy cars with low power engines get lower than the official mpg figures, because the drivers automatically compensate their right foot to keep up with the traffic.

I drive a Skoda 1.2l petrol fabia. Big enough to take a family of four camping (just). Gets average of 45mpg (me driving) (slightly less if the boss of the family drives ) but varies from 40mpg about town to 50mpg (long, steady drive). I drive as efficiently as I can.

I had an opportunity to test drive one of these new Polo Bluemotion cars at the weekend. My mum is getting one. It was quite a novelty driving a new car (mine is 13 years old). My mum should save about ?400 a year in running and fuel costs from this new car and the plan will be to keep it as long as possible, so depreciation should be less of a problem.

The car gets about 57 mpg urban, 88 combined and 70 something extra urban. During the test drive, we drove the car from cold and the fuel economy gauge, which displays an average mpg for a journey, showed only 44 mpg, rising to 50 mpg. Once the engine's warmed up, if there'd only be one person in the car and if the wheels were pumped up to the correct pressure, you should get the advertised 57 mpg.

The whole l/100 kms vs. mpg is a function of our inability to decide whether we are metric or not. I was taught metric measures (as well as imperial ones) at primary school in the 1960s, as we were supposedly "going metric" then. 40 years later, we are still going metric. I guess it's because the whole issue has become intertwined with our difficult relationship with Brussels. It is ironic that Britain has made such a fuss and such a hash of "going metric", given that it was our idea in the first place.

The mpg figure multiplied by the l-per-100km figure always give the number 278 (or, 61.16 * 4.545, to be more precise). Erm, UK Gallons, that is.
Ed:
...so, for example, 27.8 mpg is the same as 10 litres/100km.

Had a 56 plate Jazz for a while, 1.4 Sport (petrol) regularly got about 45 to the gallon though

Our Polo did 55-65mpg depending on driving when we got it (3yrs, 60k miles) However, I recently noticed that the 55 has dropped down below 50. It's done over 100k miles now, so maybe that's part of it. Or maybe the injectors are clogged up, especially as I've run a lot of veg oil through it as well as diesel. I'm running some injector cleaner through it at the moment to see what this does... then again, it could be the short trip effect - most of our journeys are 5 miles to the wood these days.

I'm running a Prius and can get nowhere near the official figures. After 12,500 miles the average consumption is 52.1mpg. It should theoretically achieve 65.7mpg. I'm 25% down on this.

Most of the driving is on flattish country A and B roads at 60mph.

RaplhW: thanks; Prius is a bit big and expensive. Not really necessary for the majority of people but there you go. The Skoda is interesting - that's pretty good mpg.

Adam1: the Bluemotion, I read a review which slagged the car for its noise - and the ordinary Polo is not especially quiet. The thought was that Volkswagen had cut the weight in some areas including soundproofing in order to save fuel. You quoted official figures, but so many journeys are short from cold, it would be rare and difficult to achieve them. Seeing as we consistently get 50+ mpg from a seven-year-old 1 litre petrol Polo, I would expect a new 1.4 diesel hyped as environmentally friendly to start at 50+ mpg. Most disappointing.

RC: !

phobos: excuse my ignorance, what's a 56 plate? (Different system here in Ireland). 45 mpg is good though.

mikepepler: that's more what I would expect from a (I presume) 1.4 diesel. There was a Peugeot back in the early eighties that got over 70 to the gallon. Of course, the gadgetry on modern cars eats into fuel but you would have thought by now that there would be a car with minimum extras achieving 100. The latest here is all Polos coming with air conditioning as standard. I don't want it! I'd rather have the mpg. Crikey, this is Ireland, air conditioning? Same with power steering - it's hard to get a car without it and really, in small cars it's a bit silly except for some disabled persons. Gimme the miles, not the frippery!

Bedrock Barney: it may be the 60 mph that knocks it back. Once you start going over an average of 40-50 a lot of cars would starting drinking fuel. There again, the manufacturers figures are misleading and not 'real world'. Console yourself that you're getting nearly twice as much as the average new Yank car!

emordnilap wrote:
Bedrock Barney: it may be the 60 mph that knocks it back. Once you start going over an average of 40-50 a lot of cars would starting drinking fuel. There again, the manufacturers figures are misleading and not 'real world'. Console yourself that you're getting nearly twice as much as the average new Yank car!

I'm fully consoled thanks!!! Car is 100% used for business. 100% capital allowance on purchase price and 40p a mile where ever I go. Built in sat nav and integrated blue tooth phone as well as 5 star euro ncap and great stereo. I didn't really buy it to jump on the celebrity bandwagon!

Gadgetry.

Agreed - probably some bells and whistles that I don't need but most of my peer group (friends and business colleagues) are driving round in top spec Jaguars, BMW's and Mercs. The depreciation and running costs must be mind boggling on a ?50,000 BMW 6 series.

emordnilap wrote:Adam1: the Bluemotion, I read a review which slagged the car for its noise - and the ordinary Polo is not especially quiet. The thought was that Volkswagen had cut the weight in some areas including soundproofing in order to save fuel. You quoted official figures, but so many journeys are short from cold, it would be rare and difficult to achieve them. Seeing as we consistently get 50+ mpg from a seven-year-old 1 litre petrol Polo, I would expect a new 1.4 diesel hyped as environmentally friendly to start at 50+ mpg. Most disappointing.

I couldn't say whether the Polo Bluemotion was noisier than any other Polo, as I hadn't been in a Polo for many years until last Saturday. My own car is a 1995 Volvo 440, which is quieter.

During the test drive, I accelerated harder than normal to see how nippy the car was. Maybe with a more economical driving style, the mpg would have started at above 50.

I expect that my mum will get around 55-60 mpg from the Polo in local suburban driving and 75-85 mpg on any longer runs. At the moment, she is getting around 33 mpg.

emordnilap wrote:You can't trust manufacturers' figures.

I think you can. In my experience they are realistic (obviously you can drive harder and use more fuel). Anyway - the absolute value isn't that important as it depends on many other variables. They should really be used as a relative measure, all else being equal, manufacturers' figures are very accurate measure of a car's relative efficiency.

clv101 wrote:

emordnilap wrote:You can't trust manufacturers' figures.

I think you can. In my experience they are realistic (obviously you can drive harder and use more fuel). Anyway - the absolute value isn't that important as it depends on many other variables. They should really be used as a relative measure, all else being equal, manufacturers' figures are very accurate measure of a car's relative efficiency.

OK, I accept that. Are they independently verified?

I'm running a Prius and can get nowhere near the official figures. After 12,500 miles the average consumption is 52.1mpg. It should theoretically achieve 65.7mpg. I'm 25% down on this.

Most of the driving is on flattish country A and B roads at 60mph.

Hi Barney,

The Prius is very dependent on temperature and the time of year.

In winter on the M-way (average 80 mph), I average 52 mpg from my Prius. In summer, this rises to an average 56 mpg. Drop to 70 mph and use cruise control and it's closer to 60 mpg.

In winter around town, I average 48 mpg. In summer, it goes up to 58.

In winter, with lights and wipers and heater, the (small) engine is working harder; in summer, it's not.

Even in winter though, and caning it hard I've never had less than 45 mpg.

My best ever figure was a slow summer cruise (30 mph) through the empty country lanes of Rutland. Up and down, foot off throttle as you peak a hill, stay off all the way down, stay of as you go up again until you either stop or somebody comes up behind. Absolutely do not try and engage the engine, and always keep the battery on charge.

Result? Average 78 mpg. OK, not typical driving, but one thing I've noticed with the Prius - it's very sensitive (up or down) to driving style.

Trick is to leave the throttle alone unless you really need it, plan ahead (watch traffic and tail lights), and always keep the battery charged by using regenerative braking so you can use the petrol motor less. My mission when driving is to se how long I can get away with not using the petrol motor

The thing I love most about the Prius though is how it's SOOO relaxing to drive - auto shift, the silence when the petrol motor isn't running. It gets you into a new way of driving - get up to speed quickly, then let the momentum carry you silently (and charging up at the same time), then a brief burst of speed, then ease off again. BLISSSSS.