WITH an official fuel consumption average of just 3.7 litres per 100 kilometres - the lowest of any car on the market - Ford has proven with its Fiesta Econetic that refinement of existing diesel technology can yield even better efficiency than a hybrid.

The new Fiesta uses a conventional five-door Fiesta body and is powered by a 1.6-litre common-rail, intercooled turbo-diesel but yields economy gains through rats and mice measures to beat the Toyota Prius’ combined 3.9L/100km figure.

Fuel consumption reduction measures include better aerodynamics in the form of 93mm of ground clearance (10mm lower than other Fiestas), additional air deflectors and specially designed wheel caps for the slim 14-inch steel wheels.

Other fuel-saving methods include Michelin Energy Saver 175/65R14 82H low-rolling-resistance tyres, low-viscosity engine and transmission oils, a taller final drive ratio, the replacement of a spare wheel/tyre with a puncture repair kit and a green ‘shift indicator’ light in the instrument panel to encourage the driver to make the optimum fuel-saving gearshifts.

The Econetic’s economy story only gets better on the highway. It achieves 3.2L/100km on the extra urban cycle - half a litre less than the Toyota Prius and 0.3L/100km better than the Mini Cooper D.

Yet the Fiesta Econetic, like all diesels, doesn’t do so well in terms of carbon dioxide emissions, an area in which the Toyota Prius is still king withy 89 grams per kilometre against the Econetic’s 98g/km.

Although the Fiesta Econetic beats fellow green cohorts in the Prius, Mini D and Honda Civic Hybrid on fuel consumption, given the different packaging and lower pricing of the Econetic, the Fiesta is not really a direct competitor for any of these cars.

The eco-Fiesta, at $24,990 on the road, is around $10,000 cheaper than the Mini D, around $12,000 less expensive than the Civic Hybrid and around $20,000 more affordable than the Prius.

The car that resembles the Fiesta the closest in packaging and price is the Fiat Punto 1.3 JTD. It has the same price, identical engine outputs from its 1.3-litre turbo-diesel engine and is a similar weight and size. The Punto’s combined fuel consumption figure of 4.6L/100km is not too far off the Fiesta’s fuel figure either.

Yet Ford president and CEO Marin Burela does not consider the Punto - now in run-out mode and due to be replaced by its facelifted replacement, the Punto Evo, late in 2010 - to be an Econetic competitor. Perhaps given the Punto’s small sales numbers it’s not surprising.

“I don’t think Econetic has a key competitor. I think we’ve carved out a niche here,” said Mr Burela, would not talk about sales numbers for the Econetic at its launch on Friday.

“We not declaring any numbers yet,” he said. “Let’s face it, we’ve only just started selling it.”

Mr Burela did concede that the Econetic’s lack of an automatic transmission would affect sales.

“Because it is a manual, it will naturally constrain the number of people that will want to go down that path,” he said.

At 1088kg, the Fiesta Econetic is at least 7kg lighter than the conventional five-door CL model upon which it is based, but the three-door CL weighs slightly less at 1085kg.

The Econetic has a full suitcase of safety gear, with a five-star ANCAP crash-test rating, seven airbags including one for the driver’s knee, electronic stability control and an anti-lock braking system (ABS).

The Econetic’s equipment level takes features from both the CL and Zetec model grades.

Standard equipment includes air-conditioning, front power windows, a height-adjustable driver’s seat, electric mirrors, remote central locking, cruise control and foglights.

The diesel fuel filler does not have a cap but self-seals and features an anti-splashback facility so that diesel fuel won’t spill back out onto hands or clothes.

The Fiesta Econetic is available in six of the nine exterior colours offered on all other Fiesta models. The palette includes Frozen White, Colorado Red, Moondust Silver, Squeeze (green), Panther Black and Vision (blue).

Like any such fuel-saving vehicles, it pays to look at the fine print if your intention is to save money. The Fiesta CL five-door petrol costs about $18,500 on the road and uses an average of 6.1L/100km of unleaded. At the time of writing, you’re saving about 3.5 cents per kilometre driving the Econetic, and so the Econetic would have to be driven for around 185,000km to pay for its $6500-odd premium.

The Econetic does have a better standard features list though, including important safety features like stability control and side airbags, which are missing on the CL (but are offered in a safety pack), so the cost comparison is not a completely fair one.

Yet even if you compare the top-of-the-range Zetec, which comes with the Econetic’s features and more, dealers are advertising those for up to $2000 less than the Econetic. On that figure, that’s still 57,000km of Econetic driving to break even.

But if you’re considering such a car, it’s not really just about saving money. It is about image, and if you want to look and feel environmentally responsible, the Econetic ensures the extra dollars make sense.