The new Mazda 3 has had a ground-up redesign on an all-new platform. This is a marginally shorter, lower hatchback than the one it replaces, but a better-packaged one in terms of interior space, says Mazda. A slightly heavier car too, for reasons that will become apparent – although a stronger and stiffer one, with the proportion of ultra-high-strength steel used in its construction jumping from 3% in the last generation to 30%.

The car continues in a broadly class-conventional vein in terms of mechanical layout, with an all-steel monocoque underbody; engines mounting transversely up front and driving the front axle only; and MacPherson strut type front suspension with a torsion beam at the rear. Get into the technical detail of the car’s design and configuration, however, and you quickly unearth evidence of alternative thinking typical of Mazda. The car’s chassis, for example, has been reinforced with ring-shaped structures intended not only to add strength but also to more quickly transmit vertical loads from the car’s suspension mountings to the base of the driver’s seat.

Matt Saunders Autocar

Matt Saunders

Road test editor
I was struck by the styling appeal of the 3, and the classy look and feel of its interior. As a slightly left-field alternative to a premium German five-door, I’d expect it to have plenty of draw.

The suspension has been redesigned to achieve similar ends, and (for the first time in recent Mazda history) works through tyres with softer sidewalls than those of the car they directly replace. Handling is aided by an electronic torque-vectoring system called G-Vectoring Control Plus, which uses brake and throttle interventions to imperceptibly but proactively balance the car’s weight between its axles during cornering and, says Mazda, to “smooth the transitions between pitch, roll and yaw”.

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The seat frames have been stiffened significantly and the seats themselves reshaped, too. All of this, together with the specific body-stiffening measures, is aimed at taking better advantage of the same biomechanical human reflexes that allow you to keep your head steady while walking, and giving the Mazda 3 what should seem like a more intuitively comfortable ride. It’s an interesting approach you won’t find many other car manufacturers following.

For now, the company is offering a choice of only two petrol engines, both with 24V mild-hybrid assistance, while an all-new diesel option is likely to follow in 2020.

Both Skyactiv petrols are normally aspirated and have 1998cc of swept volume, but it’s the more powerful of the two – the Skyactiv-X – we’re interested with here, which uses what Mazda calls Spark-Controlled Compression Ignition (SPCCI).

Combining the benefits of both compression and spark ignition, the system can actually switch from the former to the latter regime at higher loads and crank speeds. When it’s running lean, it can be between two and three times more efficient than an equivalent conventional engine by cranking up the compression ratio to 16.3:1 and by using very localised, controlled spark ignition to trigger compression ignition throughout the wider combustion chamber.

The Skyactiv-X 2.0-litre engine produces 177bhp and 165lb ft of torque at 3000rpm, so it’s unlikely to rival a downsized turbo for drivability but should do better than the atmospheric petrol average in that respect. Depending on wheel size, however, it’s claimed to deliver up to 51.4mpg for the Mazda 3 on the WLTP combined cycle, a result 13% better than the significantly less powerful 2.0-litre Skyactiv-G petrol manages in the same car – as well as a relative CO2 emissions saving of 17%.

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