ARGUABLY the most important new-car release of 2009 has arrived in the form of the second-generation Mazda3.

On sale now from $21,990 (a $500 increase over the old Neo Sport), it is not new from the ground up, but the recently independent Japanese company has redesigned the body to make it larger, roomier and more refined.

Revised drivetrains, better safety – including electronic stability control (ESC) for all models – more convenience features, improved driving dynamics, greater refinement and expected price increases complete the new, BL-series Mazda3 picture.

More than 90 per cent of the car is now recyclable, while weight gains are said to be “contained”.

A return to the original Mazda3 model nomenclature sees the Neo Sport revert to Neo, Maxx is back, Maxx Sport carries on, and SP23 turns SP25 to reflect a larger powerplant.

The Diesel version has been delayed until next year “to give the new model space to breathe”, says one Mazda insider, while the high-performance MPS model launches in about August 2009.

More than 164,000 of the outgoing BK model have been sold in Australia since it ousted the BJ 323 Astina/Protégé twins in January 2004, while about two million have found homes worldwide, making the Mazda3 number one for Mazda locally as well as globally.

So Mazda has chosen not to mess with the formula this time.

Two body styles are offered from the start, again in four-door sedan and five-door hatch guises.

Apart from the nose, which loses the grille but gains an oversized air intake shaped like those found on other recent Mazdas, the stylistic form virtually mirrors the old car. Words like “evolve” and “faithful to the previous Mazda3” abound in the press blurb.

Nevertheless, a 0.01-drop in the drag co-efficiency of the sedan (0.31 Cd) and hatch (0.33 Cd) shows progress, as do smaller panel gaps.

Mazda says better aerodynamics help quell noise, vibration and harshness issues, while increased suspension rigidity, better placement of vibration-dampening material and beefed-up body and panel rigidity also make the small car quieter.

Improved interior quality was another Mazda goal, and this manifests itself in the use of soft-grained materials on high-visibility areas such as the top of the dashboard, while the cabin’s join lines are also slimmer.

Length measurements grow by 90mm in the sedan and 45mm in the hatch, while both are 5mm taller. This translates into more room inside, and a sedan boot that is up 17 litres in capacity to 430 litres on all 2.0-litre models.

A much more efficient air-conditioner is now fitted. The heat exchanger is 20 per cent larger while the air compressor expands by 50 per cent.

Driver comfort levels also rise thanks to a gear shifter that is closer than before. Redesigned headrests enhance vision out. The main switches, buttons and other vehicular controls have been optimised to be easier to locate and use, and so are less distracting. There is a larger (4.1-inch) information display for easier deciphering. And new technology like hands-free Bluetooth and MP3 players also offer less of a diversion for the car’s operator.

Mazda has also standardised newly available satellite navigation in the up-spec Maxx Sport and SP25, meaning that more than 50 per cent of cars sold will feature GPS.

As before, a 2.0-litre twin-cam four-cylinder engine powers all petrol-powered Mazda3s, bar the sports models.

Revised for its BL application, this 1999cc unit produces 108kW of power at 6500rpm and 182Nm of torque at 4500rpm.

A six-speed manual usurps the old five-speeder, while four gives way to five-speeds in the automatic, which also includes – like before – a sequential shift facility Mazda calls Activematic.

This move means the Mazda3’s auto still trails the new Volkswagen Golf’s seven-speed DSG gearbox, but matches the Honda Civic’s ratio numbers, and now goes one better than most others such as the Toyota Corolla, Ford Focus and Subaru Impreza.

Using 91 RON unleaded petrol, the manual model’s fuel consumption falls 0.3L/100km to 7.9L/100km, while the auto’s 8.2L/100km result is 0.2L/100km lower than before.

Also on the descent are the Mazda3’s carbon dioxide emissions, pegged at 193g/km instead of 199g/km.

As its name suggests, the SP25’s engine is a 2.5-litre unit. This twin-cam 16-valve S-VT variable-valve powerplant is similar to the Mazda6’s item, and produces 122kW at 6000rpm and 227Nm at 4000rpm.

In contrast, the old SP23’s 2.3-litre engine recorded 115kW at 6500rpm, and 203Nm at 4500rpm, so improved low-down performance response is expected.

As with the 2.0, the 2.5 boasts better fuel economy (8.6L/100km versus 8.6L/100km for the 2.3 manual and 8.7L/100km for the 2.3 auto). Emissions figures rise 1g/km for the 2.5 manual at 204g/km, which is also the same rating for the 2.5 auto (2.3 auto: 206g/km).

The front-wheel-drive platform is a development of Ford’s C1 small-car architecture, but with the benefit of 1.28 million kilometres of testing in 20 locations and 11 countries the world-over.

The result is an 11 per cent quieter Mazda3 at 60km/h, due in some part to a 17 per cent jump in the use of high and ultra-high strength steels that help flexural and torsional aspects experience double-digit rises.

Weights range from 1263kg to 1398kg, compared to 1224kg to 1322kg (not including Diesel and MPS).

Mazda calls the carryover MacPherson strut and multi-link rear suspension systems “newly evolved”, with widespread modifications and alterations to help achieve an improved handling/ride balance.

The rack-and-pinion steering system is a revised electro-hydraulic set-up to help cut fuel consumption. Turning the wheel now requires less effort and offers more linearity of control, says Mazda.

Brakes are by four-wheel discs, and are supported by the aforementioned ESC, along with traction control, anti-lock braking, electronic brake-force distribution and emergency brake assist.

Also on safety, dual front airbags, active front head restraints and intrusion-mitigating brake and clutch pedals are fitted to all cars, but front-side and two-row curtain airbags cost $500 extra on the base Neo.

Mazda is aiming to sell 30,000 BL Mazda3s a year, with the Neo accounting for 35 per cent, followed by the Maxx Sport (30 per cent), SP25 (25 per cent) and Maxx (10 per cent).

The Neo’s Safety Pack uptake is geared to be at least 10 per cent, Mazda believes.

The sedan is expected to gain around 55 per cent of volume (down from about 70 per cent in the old car), while 45 per cent of all Mazda3s should be manual.