Business review: Volkswagen Polo BlueMotion

The Volkswagen Polo BlueMotion represents VW’s attempt at squeezing better fuel economy from its existing diesel-powered supermini. The changes are relatively modest but create a noticeable improvement in miles per gallon.

The base model Polo BlueMotion 1 achieves 74.3mpg on the combined cycle and an official CO2 figure of 99g/km. This allows it to slip into taxation Band A, the most economical category available, earning it a zero-cost tax disc. Within this category the Polo currently has no rivals other than short-range battery-electric vehicles such as the Reva G-Wiz, but other Band A cars will no doubt be offered by mainstream manufacturers in due course.

However, the BlueMotion 1 is a real no-frills vehicle. The addition of air conditioning in the better equipped BlueMotion 2 variant bumps up CO2 output to 104g/km and the car into Band B, where road tax costs £35 a year and there are many more rivals - from the likes of Audi and BMW as well as most of the middle-market brands like Ford, Toyota, Renault and Vauxhall.

All cars that fall into Bands A or B are due to gain exemption from the London Congestion Charge from 27 October this year, adding substantially to their financial appeal for motorists based in or near the capital.

The BlueMotion’s CO2 emissions are about 13 per cent better than a conventional 1.4 TDI Polo SE, which has CO2 emissions of 119g/km. So, what has VW done to achieve these economy gains?

To improve aerodynamics, the car boasts a new, smoother front grille, deeper bumpers and sills to better manage the flow of air under the car, plus a spoiler hugging the tailgate. Special low-rolling-resistance tyres are fitted to lightweight allow wheels that are slightly narrower than those of other Polos.

The other major changes are to the engine and gearbox. The three-cylinder 1.4-litre TDI turbo-diesel engine has a different turbocharger to alter the power/economy balance, and the gearbox has longer ratios in third, fourth and fifth, meaning that the engine spins more slowly than normal for a given road speed.

These changes clearly have their benefits, but also have drawbacks. The deeper bumpers reduce ground clearance, increasing the likelihood of damage from kerbs. Tyre manufacturers have also stated that low rolling resistance compromises wet-weather grip, so to maintain safety it is probably wise to replace tyres early - well before they reach the minimum legal tread depth.

The modified gearbox can also be vexing, giving the car a split personality. In first and second gears it feels lively and eager to accelerate. But in higher gears it becomes distinctly slothful and reluctant to increase pace. At 50mph in fifth, the engine is turning over at just 1500rpm. This combination of revs and speed works only on the flat, however: the slightest incline requires shifting down into fourth. Similarly, at motorway speeds, we found ourselves changing down much more often than normal.

Urban driving was equally hard work: 30mph in fourth equates to about 1100rpm – barely above idling speed – meaning lots of cog-swapping to avoid a labouring engine when driving around town.

On the road we often found ourselves using one gear lower than normal, defeating the point of the longer ratios. A six-speed box with conventional gears would be a significant improvement, we feel.

The diesel engine is a far from refined beast too. The vibration and clatter – very noticeable when cold and only a little more subdued when warm – leaves no-one in any doubt as to the power source.

Despite these rough edges, the BlueMotion does achieve its aims. According to the car’s trip-meter, it is very easy to achieve figures in the 60mpg to 70mpg range, while even stop-start journeys among heavy inner-city congestion saw 40mpg on the meter. Unfortunately we did not have the Polo on test for long enough to accurately verify these figures.

However, even if the BlueMotion can save emissions and so cut costs at the pumps, it still faces big financial hurdles. The conventional 1.4 TDI Polo SE model also sits in VED Band B and probably represents better value for money.

The Polo BlueMotion 1 has a base on-the-road price of £12,120 for the three-door, including VAT. The equivalent BlueMotion 2 costs £12,935. The comparable Polo SE, meanwhile, costs just £11,825 and is better equipped than either BlueMotion model. At current prices, it would take about 150,000 miles for the BlueMotion 2 to recoup its purchase premium over the SE through reduced fuel usage, based on official consumption figures.

In summary, the BlueMotion is reasonably effective at what it does but seems optimistically overpriced. We would suggest that interested buyers should negotiate hard for a discount.