Fuel use figures “still way off mark”

Long Queues at Petrol Stations and Panic Buying ahead of Possible Driver Strike
  Although pump prices are at their lowest level for four years, a gallon of unleaded still works out at well over a fiver – which means fuel consumption remains a big consideration when choosing a new car. The trouble is, manufacturers’ fuel consumption figures still can’t be trusted. Despite widespread coverage of how manufacturers can manipulate a motor’s miles-per-gallon (mpg) ratio, the latest batch of True MPG test results from WhatCar? show how advertised fuel consumption figures are still well off the mark.

How is MPG worked out?

Manufacturers work out mpg under three types of test condition – urban, extra-urban, and combined. The assumption is that most drivers will usually cover one or more of these test conditions as part of their normal routine. The problem is that these tests aren’t carried out on real roads. They’re performed in laboratory conditions, on rolling roads with no headwinds or inclines to add to consumption figures. Results are manipulated even further by pumping up tyres extra hard to reduce rolling resistance, removing mirrors to reduce wind resistance and even disconnecting brakes to ease friction. All this means the results are anything but realistic. WhatCar? set up a series of True MPG tests to give motorists a better idea of fuel consumption  and some results varied considerably.

How is True MPG is worked out?

To get a more accurate view of ‘real-world’ fuel consumption, the WhatCar? mpg test involves vehicles being driven over a variety of real roads, including motorways, A roads, B roads, in towns and in villages. Almost 400 cars have been tested under these conditions and results show that vehicles achieve economy figures that are an average of 19% lower than the manufacturers’ figures. WhatCar? editor, Jim Holder said: “Our True MPG test figures are reliable and achievable. Drivers, unfortunately, cannot trust the government-sanctioned data because the tests are carried out in a laboratory. “However, most buyers consider fuel consumption to be among the most important attributes of a car. That is why motorists should visit our website to check how well the car they intend to buy really performs.”

Performance data

So which cars are among the best and worst performers when it comes to real-world versus laboratory-test fuel consumption figures? The VW Golf SV 2.0 TDI is currently in pole position, achieving 83% of its claimed fuel consumption of 58.9mpg. Back in the pits, meanwhile, is the Volvo V40 2.0 T5 R-Design, which delivered 32.5mpg – just 67.9% of its claimed 47.9mpg.

Here is a rundown of the latest cars tested for True MPG, courtesy of WhatCar?:

 
Model Official MPG True MPG % of official achieved
Audi A3 Saloon 1.6 TDI Sport 72.4 52.7 72.8
Audi A3 Cabriolet 2.0 TDI 67.3 46.3 68.8
Audi A6 2.0 TDI S line 61.4 47.8 77.9
BMW 218d Active Tourer 68.9 56.2 81.6
Mini Cooper 1.5 D 78.5 58.7 74.8
Toyota Yaris 1.33 VVT-I 78.5 57.8 73.6
Volvo V40 2.0 T5 R-Design 47.9 32.5 67.8
Volvo V40 2.0 D4 X-Country 70.6 55.9 79.2
VW Golf SV 2.0 TDI 58.9 49 83.2
  Does your car perform anywhere near the expected mpg? Let us know in the comments section or on Twitter using the hashtag #FocusonFuel

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