First drive: Sky is the limit, says Mazda

IT IS not often a car-maker lets journalists loose in – and requests feedback on – prototype vehicles underpinned by chassis and engine technologies that remain years away from production, but that’s precisely what Mazda did during a global ‘technology forum’ in Berlin last week.

GoAuto was one of just 40 media outlets in the world invited to test its future model technologies – including revolutionary new Sky G petrol and Sky D diesel engines, a revolutionary new sixth-generation chassis and the upcoming Sky Drive automatic transmission – in four pre-production mules officially known as ‘technology prove-out vehicles’, or TPVs.

The first Sky technologies will not make their way into Australian showrooms for at least 12 months – in the form of a 2.0-litre Sky G petrol engine and six-speed Sky Drive auto in selected versions of next year’s facelifted Mazda3 small-car – and the first Mazda model to combine the all-new lightweight chassis with Sky powertrain technology is unlikely to emerge in Australia before 2013, in the shape of the redesigned Mazda6.

Along with the unprecedented chance to test the four-cylinder engine and front-wheel drive chassis technologies that will underpin the next generation of Mazda models first hand in real-world European conditions, Mazda revealed a range of outstanding performance and efficiency statistics for its Sky engines.

Despite the fact the brand-new chassis – which will underpin the next-generation Mazda6, the all-new Mazda3 due in 2014 and a range of SUVs including the all-new sub-compact CX-5, redesigned CX-7 and, perhaps, a new CX-9 medium SUV – will not be fully developed for up to 18 months, it is clear Mazda’s focus on lightweight chassis development has paid handsome dividends.

Equally, despite being a year away from production and with its new automatic transmission requiring a significant amount of calibration work, Mazda’s new Sky engines appear to be well on target to achieve big gains in both performance and refinement - while meeting formidable new efficiency targets that should realise Mazda’s commitment to reduce the average fuel consumption of its new model fleet by 30 per cent between 2008 and 2015.

Mazda’s plan to deliver ambitious fuel consumption and CO2 emissions reductions by developing conventional internal combustion engine technology to previously unseen levels and achieving outstanding weight reductions for all of its future models has been well documented.

But even more impressive than we expected are the first fruits of its ‘building block’ strategy, which is designed to deliver maximum efficiency gains for the widest possible range of customers without (at least initially) the use of expensive fuel-saving electrical devices like brake energy regeneration and petrol-electric hybrid drive systems.

GoAuto sampled both the upcoming 2.2-litre Sky D turbo-diesel engine and the 2.0-litre Sky G petrol engine – each equipped with new six-speed manual and automatic transmissions – in Mazda’s new sixth-generation chassis.

Mazda did not officially specify which model the Mk6 platform would first appear beneath, but provided a number of comparative figures that made it clear what we were driving was, in fact, the next-generation Mazda6 that is not due to appear for at least two years.

Cobbled up beneath the bodywork and interior of the current Mazda6 and wearing a number of riveted panel sections to disguise the fact it is shoehorned within more compact exterior body dimensions, the all-new platform comprises a 50mm-longer wheelbase combined with 18mm and 25mm wider front and rear wheel tracks respectively.

Unlike today, the larger Mazda6 platform will serve both the US and other global markets.

Driven over a range of German roads – including everything from stop-start traffic to unrestricted autobahns – both engines were considerably quieter and more refined than the ones they replace.

In particular, the beefy new twin-turbo diesel, which delivers similar peak power of 136kW but considerably more torque at 420Nm, emits a characteristic diesel clatter only during idle when cold, spins more smoothly and freely to a higher 5200rpm redline and feels a great deal stronger, both from idle and between 2000 and 4000rpm, with maximum torque produced at just 2000rpm.

On the road, that makes the Mazda6 diesel more flexible and European-like, and at one stage we were able to accelerate cleanly and briskly from less than 60km/h to well beyond 200km/h in sixth gear (manual).

Mazda engineers revealed they used BMW’s 135kW/380Nm 2.0-litre diesel engine as their benchmark for Sky D development and they appear to have hit their targets.

The icing on the diesel cake is fuel consumption that Mazda says will average an astonishing 4.2L/100km in both manual and automatic guise (down about 20 per cent), which, along with CO2 emissions of just 105g/km (down 23 per cent), matches the efficiency of most light-sized cars available in Australia.

The Mazda6 Sky G mule with the new naturally aspirated 121kW/210Nm 2.0-litre inline petrol four was just as impressive, delivering strong take-off acceleration and revving sweetly to beyond 6000rpm and offering more muscular mid-range performance more progressively than Mazda’s existing 2.0-litre petrol engine while also being quieter and more refined.

Fitted in the Mazda3, where we will first see it, the 2.0 Sky G engine will return just 6.0L/100km with the new six-speed Sky Drive automatic, which offers super-slick and quick upshifts and should come fitted with both idle-stop and paddle shifters as standard, but at this stage remains a little abrupt during downshifts.

The upgraded six-speed manual feels more MX5-like with its shorter throws and more positive shift action.

Mazda’s Mk6 chassis makes similar advances and is claimed to offer best-in-class torsional rigidity, making it even stiffer than the mid-sized European sedans against which it was benchmarked, including the BMW 3 Series, Audi A4 and VW Passat.

A reworked trailing-arm independent rear suspension system produces less lift at speed and under brakes, while a redesigned strut-type front suspension (to replace the current wishbone architecture) is simpler, cheaper and separates the shock mounts from the lower control arm to improve ride quality over high-frequency road bumps.

Eliminating a bug-bear of the otherwise well-sorted electric power steering system in the current Mazda6 is a redesigned EPAS system with an electric motor located not on the rack but the steering column, resulting in improved straight-line feel and precision, and more linear power assistance away from centre.

Along with the considerably stiffer and lighter chassis, the new steering set-up gives the Six improved low-speed agility and high-speed stability.

The Mazda6 has always been at the leading end of the mid-size Japanese car class, but a wholesale redesign using BMW’s accomplished 3 Series as a yardstick appears set to make it quite noticeably even more European-like.

At the same time, Mazda’s thoroughly effective Sky powertrains look like achieving the hitherto impossible double-act of delivering both class-leading performance and economy.

This is even before they are assisted with the introduction of fuel-saving regenerative braking and hybrid drive systems that are due to come online – the latter in concert with Sky G petrol power – by 2015.