Driven: Mazda3 XD Astina diesel joins the range

MAZDA has introduced its most fuel-efficient Mazda3 to date with a new range topping 2.2-litre bi-turbo diesel XD Astina joining the line-up, alongside existing 2.0-litre and 2.5-litre petrol engined versions.

When optioned with a six-speed manual gearbox the $40,230 XD version is Mazda’s only manual diesel vehicle and uses 5.0-litres of fuel per 100km - 0.7-litres less than the previous Mazda3 diesel and current 2.0-litre petrol - while producing 129g of CO2 per km.

Crucially, the new XD Astina is the first compression-ignition Mazda3 to be offered locally with an automatic transmission - a move aimed to boost the appeal of the diesel in auto-centric Australia.

Moving up to the Skyactiv-Drive six-speed automatic transmission adds $2000 to the price of the manual XD, making it the most expensive variant in the Mazda3 line-up. But with the most standard equipment of the range, the diesel version takes the $38,190 (automatic) SP25 Astina’s place as the new flagship.

Fuel consumption for the auto rises slightly to 5.2 L/100km, as too does CO2 emission, up 8g to 137g/km.

The same engine powers diesel variants of the mid-size Mazda6 and CX-5 compact SUV and may give the Mazda3 a fighting chance against its arch rival - the Toyota Corolla - which is not available with a diesel.

With the most standard equipment of any Mazda3 and a more powerful diesel engine, the Japanese car-maker is also going after sporty small hatch offerings from other brands, with Subaru, Volkswagen and Ford all in its sights.

Available only as a hatchback, the XD Astina shares all of the equipment of the previous top-spec car - the SP25 Astina - but is distinguishable by “bright” 18-inch alloy wheels, black highlights to the front and rear bumpers, a red front grille accent and LED fog-lights on the outside, and a black leather/suede interior.

Its Skyactiv-D 2.2-litre diesel engine has one small turbo for low-lag, low rpm boost and a larger turbo, which takes over at higher rpm to produce the full 129kW and 420Nm, and accelerates the XD to 100km/h in 7.7 seconds in the manual (8.4s in the auto) and on to a top speed of 216km/h (212km/h auto).

Under mid-load conditions the two turbos work in conjunction, altering their share of the boost depending on the driving style. Boost air is sent through an air-to-air intercooler to improve its charge-density.

The use of an aluminium cylinder-block, reduced casting wall thicknesses and lightened crankshaft has stripped 42kg - about two bags of cement - from the diesel engine compared to the previous MZR-CD 2.2-litre engine, further adding to its potential fuel-savings.

Variable valve-lift has increased the diesel’s volumetric efficiency, egg-shaped piston crowns dissipate the 2000bar injector spray more evenly and overall oxides of nitrogen (NOx) emissions have been cut.

The new diesel also gets i-stop fuel saving idle-stop technology, which cuts the engine when stationary in heavy traffic for example.

Most existing idle-stop systems use the starter-motor to restart the engine when required, which draws energy from the battery, but Mazda’s i-stop system cleverly stops the engine with one cylinder under full-compression.

When the engine is required to restart, the injection of diesel into the combustion-chamber initiates combustion and the engine fires-up without the use of electrical energy.

The XD is the first Mazda3 to use Mazda’s i-eloop energy recovery system, which allows further electrical energy saving by converting the vehicle’s kinetic energy on overrun into electricity and stores it in a double-layer capacitor.

Under acceleration, the capacitor supplies electricity to the vehicle’s various systems rather than the alternator, which would apply extra load to the engine and increase fuel consumption.

The diesel version also gets Active Engine Sound, which plays a more satisfying engine note through the speaker-system compared to the un-enhanced diesel noise.

The Skyactive-Drive six-speed automatic transmission uses a 100 per cent lock-up clutch to increase cruising fuel-efficiency and has a bespoke ratio-set for the new diesel variant to make optimum use of its greater torque.

Despite the range-leading economy and comprehensive equipment list, Mazda does not expect the XD to be a volume-seller, with just a two percent stake of the Mazda3 range predicted to be diesel sales.

That figure translates to around 300 sales by the end of 2014 - the lowest of the range - with 2.0-litre petrol Maxx variants taking out approximately one third of all sales.

Other than its engine, black leather/suede seats and mild exterior styling changes, the Mazda3 XD Astina is identical to the top-spec petrol SP25 Astina.

A sunroof, top-spec 231-watt Bose sound system, head-up display, adaptive cruise control, blind-spot monitoring, forward-collision braking, automatic headlights with auto-dip and rear cross-traffic alert systems are all shared with its spark-ignition sibling.

The XD also gets all of the equipment from the rest of the SP25 range, including bi-Xenon adaptive headlights, LED daytime running and tail-lights, rain-sensing wipers, keyless entry/start, dual-zone air-conditioning, satellite navigation and heated front seats with power adjustment for the driver.

Information and entertainment systems are also top-spec in the XD Astina with Mazda’s ‘human machine interface’ HMI system, which incorporates a seven-inch TFT screen, head-up display and in-dash display to offer both driver and front passenger required information with minimal distraction.

The system uses the MZD Connect system of controls to access all vehicle information, navigation, smart-phone functions and entertainment systems.

Pandora, Stitcher, Aha Radio as well as Android and iPhone operating systems are all supported along with a variety of other applications.

All variants in the 2014 Mazda3 range get six airbags including full-length curtain bags, Bluetooth connectivity, USB inputs, two-way adjustable steering column, cruise control, hill-hold assist and 60/40 split rear folding seats with ISOFIX anchors.

Interior space and capacity is unchanged from other hatch variants in the range with seating for five, 956mm of headroom in the front compared with 952mm at the rear and a 308-litre boot.

As with all 2014 Mazda3 variants, the XD benefits from Mazda’s SkyActiv chassis developments, which have resulted in 31 per cent increased body torsional rigidity and a 38 per cent weight-reduction over the previous model.

Chassis layout is also identical with 14.1:1 electric power steering, MacPherson strut suspension up front, multilink suspension in the back end and disc (ventilated front) brakes all round - although the XD rear dampeners are slightly fatter to deal with its greater mass and torque.

All its kit and diesel engine gives the XD the heaviest kerb weight of the range at 1448kg (1465kg auto), and its towing capacity has not increased over the lesser variants in the range, remaining at 1200kg braked and 600kg un-braked.

With the exception of Mazda’s trademark Soul Red, all colours including the new Deep Crystal Blue Mica and Titanium Flash Mica are available at no extra cost.

2014 Mazda3 pricing*

Neo	$20,490
Neo (a)	$22,490
Maxx	$22,990
Maxx (a)	$24,990
Touring	$25,490
Touring (a)	$27,490
SP25	$25,890
SP25 (a)	$27,890
SP25 GT	$30,590
SP25 GT (a)	$32,590
SP25 Astina	$38,190
SP25 Astina (a)	$38,190
XD Astina	$40,230
XD Astina (a)	$42,230

*Excludes on-road costs.