Australia is one of the world’s most important markets to Mazda. So it comes as no surprise that local motoring journalists have been given an in-depth review of major engineering changes of upcoming Mazda models.

Mazda’s Skyactiv project covers all aspects of vehicle design and we were honoured to have senior members of the Japanese team visit our shores. These included the chief project planner, Kiyoshi Fujiwara, and the general manager of powertrain development, Mistuo Hitomi, as well as several senior engineers.

Better still they brought one of their prototype vehicles for us to test drive. The testing had to be done under controlled conditions at Sandown racetrack as the vehicle can’t be driven on public roads. In any case a prototype like this is worth several million dollars so couldn't be subjected to the dangers of Melbourne traffic.

The test vehicle was a current model Mazda6 on the outside, but underneath it was fitted with a special new design of engine, automatic transmission and suspension. Changes in design of these new components meant the test vehicle weighed slightly less than the standard car. Mazda says significant reductions in mass will be made when an all-new body is introduced.

The most startling features of the new engines are the compression ratios. Typically a modern petrol engine runs at about 10:1, with very-high performance units going up to as much as 12.5:1. Mazda engineers have managed to get their Skyactiv engine up to 14:1, a seemingly impossible figure until now. This ultra-high compression has been achieved without creating ‘knocking’ within the engine by reshaping the piston tops and greatly extending the length of the exhaust extractors.

However, it’s likely that Australia will get a detuned version of the engine because many are reluctant to pay for the 95 high octane petrol, preferring instead the lower grade 91 octane. Using 91 will result in higher fuel consumption, probably in the range of three to four per cent higher and with lower engine performance as a result.

Just as surprisingly, the compression ratio of the turbo-diesel engine is also 14:1, the same as that of the Mazda petrol engine. In diesels a lower compression ratio reduces emissions and helps improve performance. The figure of 14:1 is substantially lower than the 16:1 to 18:1 seen in other modern diesels.

The only engine brought to Australia for us to test was the Skyactiv D (for diesel). On the track it’s difficult to replicate real on-road conditions, but the Skyactiv turbo-diesel we tested got off the line gently and accelerated without any hesitation.

Once underway it displayed minimal turbo lag and was happy to rev to 5200 rpm, whereas most diesel engines start to fade once they are over 4500 revs. This higher speed of the Mazda unit is a direct result of the lower compression ratio as this permits lighter internal components as there is less strain on them. The higher revs gave the Skyactiv D engine a really sporty feeling.

Noise levels from inside the car were low, but it still had the typical idle rattle that was quite obvious from the outside. This is a prototype and sound insulation design will obviously be better on the production model.

All-new designs of both automatic and manual transmissions are part of the Mazda Skyactiv program. These display clever thinking both in the way they have been simplified and reduced in weight. On the Sandown track the six-speed auto in the car we tested had sharp shifts that felt noticeably quicker than those in conventional automatic transmissions.

Mazda tells us the lighter bodies, completely redesigned engines, transmissions and suspension, plus many other smaller changes reduce fuel consumption by between 20 and 30 per cent.

European marques are using smaller engines and turbocharging them to reduce consumption and emissions. Mazda’s move to stay with engines of the same capacity but use all-new technology is an interesting one. It eagerly wait to see which is the correct answer. Of course it’s possible that both schools of thought are right and buyers will have a wider choice between technologies.

The Mazda Corporation says that while it’s working on ways of reducing the environmental impacts of its vehicles it will not take away any of the pleasure they provide to drivers. The Japanese company has had a lot of success with its Zoom-Zoom campaign since it began almost a decade ago, and is adamant that driving enjoyment will remain one of its strongest features.