MPG half of that advertised! How to get out of car agreement?

Tobster86

27mpg is at the pessimistic end of a typical V8 saloon on the motorway (my 540i manages about 30), and just ridiculous from a 0.9.

I strongly suspect something, probably quite benign, is wrong with it. Can you smell petrol after it's been stood for a while?

I'd advise having it looked over by a suitable car expert. Be aware that many mechanics these days are not car experts.

Strider590

Tobster86 wrote: »

Be aware that many mechanics these days are not car experts.

Especially those at dealerships.

Johno100

Strider590 wrote: »

It's just the way the industry is these days, they run the mpg tests on cars on rolling roads, with most of the interior stripped out, zero wind resistance and with an expert doing the driving.

Don't they also tape over the panel gaps? I think the only useful purpose manufacturer's MPG figures serve is as a comparison with other vehicles on the same basis.

kripel

it's a 0.9 Petrol Engine and you are mostly using it for high-speed motorway driving- that's really the problem
I also get super low mpg when I drive my 1.2 over 110km/h.
Those little petrol engines are great for speeds of 90km/h and they are super economical at those speeds, but make them work harder and they will consume more fuel than a bigger engine car.

Also yes I really find it hard to believe that ,that car would get 67mpg from petrol engine, More like 45-50mpg when you are driving super economical.

WobblyDog

Are you sure you are calculating the fuel consumption correctly ?
A good way to calculate it is across several large fill-ups (and at least several hundred miles), using the figures on the filling-station pump and the car's odometer.

wongataa

Johno100 wrote: »

Don't they also tape over the panel gaps?

There is no need to do that. Fuel consumption tests are carried out on a rolling road inside a test chamber. The car doesn't actually move so any aerodynamic tweaks are not needed.

mb101_2

I think you have the answers in this thread now...

1. You should not expect to get 67mpg driving a 0.9l petrol down the motorway, but you should expect to get more than 27mpg as Tobster86 suggests... unless you're thrashing along at 90mph. I assume you are not doing that? (Note that, from some diesels, you probably could get close to 67mpg, though not if you are doing much over 70mph.)

2. As per WobblyDog, calculate the MPG you are actually getting (at or around 70mph).

3. Assuming it is close to 27mpg, take your car to an Alfa Romeo dealer, because its still under the manufacturer's warranty if it's a 2013 car, provided all servicing requirements have been met. Ask them nicely to test it and fix it under warranty.

This is the best you can do. As far as I am aware (although I am not a lawyer) you would not be able to get out of the finance deal just because you cannot match the combined cycle MPG on your commute.

jimjames

Hanspence wrote: »

Thank you ever so much for the constructive messages guys!

I am just wondering who is liable for these mpg figures. If, as said above, they are tested so they look good for speed and performance- surely that is false advertising?
I agree that I have little chance of getting out of this however consumers (me included) use the mpg figures to make an informed purchase. When these are hugely innacturate, someone must be responsible ?!

Have you actually measured the MPG or are you relying on the car readout?

Herzlos

mb101 wrote: »

(Note that, from some diesels, you probably could get close to 67mpg, though not if you are doing much over 70mph.)

I doubt you'd get close to the advertised figure at 70mph either, I need to be going about 55-60mph to get close to mine. The car doesn't spend long at that speed in the official test:

The extra-urban cycle is a cycle that is intended to represent the use of the vehicle on roads that are external to the urban environment. The cycle is conducted immediately following the urban cycle and consists of roughly half steady-speed driving with the remainder being accelerations, decelerations, and some idling. The maximum speed is 75 mph (120 km/h). The average speed is 39 mph (63 km/h) and the distance covered is 4.3 miles (7 km). The cycle is shown as Part Two in the diagram below.

The acceleration levels required by the test are also incredible, the car is allowed either 60 or 120 seconds to get up to the 60mph (I can't find a source), but in either case it's in getting-overtake-by-impatient-tractors territory.

DominicH

Strider590 wrote: »

As mentioned, small engines are not always more efficient and I imagine it has to work quite hard at 70+ mph just to maintain that speed.

Where my Vectra mpg actually goes up by 10 on a long motorway run.
[...] on the motorway that weight carries momentum and it needs less fuel to stay up to speed, so I get 40-45mpg.

So are you saying that if you take a small car on a long motorway drive, it would be more efficient if it were carrying a greater load? Say, some bricks in the boot, or extra passengers?