Economy Marathon Surprises

Posted on October 13th, 2011 by Rob Marshall

Economy Marathon SurprisesA common complaint, in these harsh times, where every expensive drop of petrol is precious, is that reaching many cars’ Official Combined Fuel Consumption figures can be virtually impossible for most drivers. In truth, the car manufacturers have not been engaging in skulduggery, as may be thought, because the figures are established by independent means. However, many companies design their cars to achieve the highest miles-per-gallon (MPG) figures and lowest CO2 emission results possible in the European test labs. While the vehicle might perform well in the exam,  when confronted with real life situations, the owner can be left disappointed by the cars’ frugality, or lack of it. Clearly, buying the right car is essential but, with the official figures being so difficult for many drivers to attain, it is clear that some buyers are making the wrong choice.

This is what made the entrants in the 2011 ALD Automotive/Shell/ Fleet World MPG Marathon, held earlier this month (BBC coverage of the event is here), so interesting. With cars that ranged from both petrol and diesel hybrids to a thunderous 6.2-litre Vauxhall VXR8, the fascinating thing for me was not the maximum MPG figure attained (which was the 99mpg, posted by a smart fourtwo diesel,) but how many miles over the Official Combined figure could be realised over two days and almost 400-miles worth of driving, which took the cars on a pre-determined route, from the Cotswolds, into the roads of Somerset and Hampshire and back again.

As in previous years, I was invited to navigate for my colleague, motoring journalist, Iain Robertson, and together we have performed strongly, including winning the event outright three years ago. However, this year, instead of plumping for a supposed ‘eco’ car, our tool-of-choice was a 5.0-metre long, 2-tonnes, turbocharged Saab 9-5 2.0T Aero petrol, which boasts an Official Combined figure of 34.4mpg.

Despite the car’s bulk, it was the Saab’s on-road manners that gave both Iain and me one of the most comfortable and relaxed eco-drives that we have experienced together. The car’s twin-scroll turbocharger can not only provide sparkling acceleration but, when driven appropriately, it will enhance low-engine speed efficiency. To test this, we managed to climb several fairly steep hills at below 1,000rpm, without experiencing a trace of engine judder or complaint. Yet, despite the inclines, heavy traffic through Circencester and heavy rain (which added to tyre drag), the big Saab returned an average of almost 44mpg, a result that improved on its Official Combined figure by 27%, which was enough to earn the car (and us) a podium finish in our class, to the surprise of many onlookers.

Interestingly, only six cars failed to reach their Official Combined figures, including every hybrid model entered. Yet, the gap between the eco models’ improvement and the high-performance cars was startling. For example, two Volkswagen Golfs participated; an ‘eco’ 1.6-litre ‘Bluemotion’ diesel, which improved on its official 74mpg by almost 6% and a high-performance 268bhp Golf R, 2.0-litre petrol-turbo, which enhanced its 33.2mpg figure by an astonishing 48%. The Golf R, along with several other models, including the Saab, proved that the biggest efficiency gains were achieved by the higher-performance models.

THE DRIVER’S ROLE

Obviously, the style in which the cars were driven was crucial to the end result. Yet, driving economically does not mean progressing at a mind-numbing rate, which one Kia-piloting participant proved aptly, by driving so sedately that other road-users were held up. Intriguingly, that car was one of the few that failed to achieve its Official Combined figure.

According to Iain, the driver of the Saab, an essential key to obtaining excellent fuel economy lies in driving smoothly. Planning as far ahead as possible may be vital to advanced driving techniques but it also avoids unnecessary fuel-sapping stops. In addition, accelerating progressively to a more efficient cruising speed, then throttling back and even using that potential to pass slower vehicles, proved to be the most effective means to driving economically. Naturally, fuel-guzzling features, such as the air conditioning, were switched off in the Saab.

In these days of runaway fuel prices and a constant pressure to reduce vehicle costs, the event has proved that not only will realistic, careful and thoughtful driving achieve the desired economy results but that the non-eco models also have the greater potential to at least achieve or even exceed their Official Combined fuel figures by a considerable margin, when confronted with everyday situations outside of the laboratory.