Mazda: Plenty of activity cuts fuel thirst

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Using absolutely conventional powertrain technology, Mazda has slashed the fuel consumption of the Mazda3 2.0-litre by more than a quarter. Surely that's one of the most amazing automotive achievements of the year? Well, yes. And no. But probably yes.

SkyActiv is the name of Mazda's next-generation powertrain and chassis technology. It's been launched with the facelifted Mazda3 range this week - albeit in a single model, the GSE SkyActiv, which features a new-design 2.0-litre petrol engine and six-speed automatic gearbox. The GSE is based on the standard GSX 2.0 (which carries over the existing 2.0-litre engine and five-speed automatic), so there's an easy comparison: the GSX makes 108kW/182Nm and returns 8.4 litres per 100km in the official Australian design rules (ADR) economy cycle. The new GSE SkyActive produces 113kW/194Nm and achieves 6.2 l/100km in the same test. There's your 26 per cent improvement. Pretty incredible, and perhaps more incredible for the Mazda3 than it would be for many other small cars, given that it was already one of the thirstiest models in the class. Let's face it, the Mazda3 has always liked a drink, even in small-capacity 2.0-litre form.

It had a bit of catching up to do, when rivals such as the Holden Cruze iTi (6.9 l/100km) and Ford Focus 2.0 (6.4 l100km) are already so thrifty.

Still, 6.2 l/100km thrusts the Mazda3 GSE to the top of the class for fuel economy, and that's worth celebrating. An amazing achievement? Let's say yes.

Consider the GSE SkyActiv simply a taster. The technology will be in every new Mazda from now on - the first with the full package being the CX-5 compact crossover, expected next year. It will be the real deal: SkyActiv powertrain and chassis. The Mazda3 GSE, based on a present model, gets only the engine and transmission combo at this stage.

SkyActiv is a cool brand the company can attach to the back of every GSE. But it's also a rethink and redesign of every component in a conventional engine and transmission to gain maximum efficiency and, therefore, maximum economy.

For example, the Mazda3's SkyActiv 2.0-litre has reduced internal friction, thanks to redesigned pistons and connecting rods (127g for each cylinder), and thinner conrods. The direct-injection system is tailored to the most efficient combustion possible, with multi-hole injectors and a very high compression ratio. In Europe, the car runs at a remarkable 14:1 ratio. For New Zealand and Australia, it has been reduced to 12:1 to allow the GSE to run on 91-octane fuel.

Mazda says its SkyActiv-Drive automatic transmission is just as responsive and economical as dual-clutch units used by rivals Ford (Powershift) and Volkswagen (DSG). It has a very small torque converter and locks up early - beyond about 5km/h - for efficient and smooth gear changes. So, a thorough rethink but nothing radical.

The most unusual feature of SkyActiv is the addition of Mazda's i-stop system, which cuts the engine when the car comes to a halt at traffic lights and restarts automatically when you want to go again. It's familiar technology from other makers, but Mazda has rethought it for the SkyActiv application. While other systems use the electric starter motor to fire up the engine, this one stops the pistons in exactly the right place to use the combustion process to restart. The company says SkyActiv i-stop takes about half the time of a conventional system to restart.

The Mazda3 GSE SkyActiv costs $37,395, a $2100 premium over the GSX. At present prices you'd have to drive the GSE 40,000km to make up the price difference in reduced fuel costs, but the case for SkyActiv is more comprehensive than that. Mazda NZ says there's now a case for the car with fleets that have specific C02 requirements that put the standard GSX at a distinct disadvantage against some rivals. And, says the company, the SkyActiv car is a much better drive.

Agreed. We drove the GSE and GSX back to back. The SkyActiv car has a crisper throttle response, is quieter and more sprightly. The only complaint was a marked reluctance from the SkyActiv-Drive gearbox to kick down under medium throttle pressure - it's obviously calibrated for maximum economy, but you can override the computer with a manual-change facility. When you do, the changes are fast, no-fuss.

The GSE SkyActiv is just one model in a revamped Mazda3 range. Exterior styling is now more conservative across the range as Mazda moves towards a new design template. The striking smiley face has gone in favour of a new grille and front bumper design with straighter lines.

The interior has been tweaked with a new dashboard that peels back the "hood" over the main instrument binnacle and brings added equipment. All models now have Bluetooth cellphone connectivity. The entry GLX has gained cruise control, the mid-range GSX/GSE gets dual-zone air-conditioning and foglights, and the SP25 now features a sunroof, automatic lights/wipers and keyless start as standard.

Prices for the mainstream Mazda3 models have risen by just $100 to $200 depending on model, while the luxury SP25 and high-performance MPS versions are up $800 to $1000.