Engines &

The Mazda2 is available in the UK exclusively with a 1.5-litre naturally aspirated Skyactiv-G petrol engine that’s offered with a choice of two power outputs: 75ps and 90ps. The 75ps engine is available in SE-L Nav trim, while the 90ps version makes up the bulk of the range and is offered in SE-L Nav, Sport Nav and GT Sport Nav trims.

For the first time in the Mazda2, the 1.5-litre naturally aspirated Skyactiv-G petrol engine is matched to Mazda’s M Hybrid mild-hybrid system to deliver lower running costs and strong environmental credentials. Standard on all Skyactiv petrol engines with a manual transmission, Mazda M Hybrid technology uses a small Belt-Integrated Start Generator (B-ISG) to capture and store kinetic energy from regenerative braking and repurposes it to improve efficiency. As a result, manual versions of the Mazda2 have emissions from as low as 120-121g/km and economy of 53.3mpg on the combined cycle. All models now feature a six-speed Skyactiv manual transmission as standard, while in Sport Nav trim you can also choose a six-speed Skyactiv-Drive automatic transmission.

When developing the 1.5-litre engine, Mazda’s engineers eschewed the current trend of exploiting tried and tested technology such as forced induction and downsizing engines, and opted instead for a fundamental rethink that would allow them to ‘right-size’. The result was the 1.5-litre all-alloy engine which uses advanced technologies – including intelligent direct fuel injection, low-friction design, and a compression ratio of 13:1 for both power output engines - to deliver high levels of economy, refinement and flexibility without compromising performance.

In the Skyactiv-G petrol engine, the top-dead-centre temperature remains lower than the last generation engine, halving the level of residual exhaust gas from eight to four per cent, while introducing an extended and looped four-into-two-into-one exhaust system prevents exhaust gas leaving one cylinder being forced into the combustion chamber of another. In addition, the piston heads are fitted with cavities to prevent the initial combustion flame from hitting the piston and interfering with the flame’s growth, and low-temperature oxidation – an exothermic reaction in which the bonds within the molecules of petrol break and produce energy – were exploited to further boost torque across the rev range.

The 90ps variants use an innovative four-two-one exhaust manifold, which lowers the in-cylinder compression temperature to help prevent knocking (unwanted premature ignition), improve the scavenging effect and with it combustion efficiency, and deliver extra torque – especially at low engine speeds. The ‘standard power’ 75ps version of the 1.5-litre Skyactiv-G petrol engine has a 13:1 compression ratio, variable valve timing on the intake manifold only and simpler four-into-one exhaust manifold. Despite its smaller exhaust, simpler valve timing, lighter engine cover and smaller oil pump, this version still produces more torque than Mazda’s previous-generation MZR 1.3-litre petrol engine.

Working in conjunction with the Mazda M Hybrid system, all versions of the Mazda2 are equipped with the i-stop idle-stop technology as standard. Developed entirely in-house and tailored specifically for its application in Mazda’s Skyactiv engines, the i-stop idle-stop system uses combustion energy for restarting the engine, and only requires an electric-powered starter motor to provide a small degree of momentum during the initial restart phase.

The lightweight Skyactiv six-speed manual transmission – found on both the 75ps and 90ps models – delivers the same effortless, crisp and precise wrist-flick gear changes, as those enjoyed by MX-5 drivers. The key element to achieving this quick and decisive gearshift action is a larger gear lever ratio, but this in turn effectively reduces the internal stroke. To counter this, Mazda’s transmission engineers developed a small module spine that allows for exceptionally precise synchroniser and torque transmissions even with the desired 45mm short gear lever stroke. Shift effort gradually falls away during the gearshift action, resulting in a reassuring resistance during the initial movement of the gear lever, followed by a lighter touch to create the tangible feeling of the gears meshing cleanly in to place.

Combining competition-beating torque capacity with lower internal drag, the six-speed transmissions require 45 per cent less transmission oil than previous generations. The Skyactiv-Drive six-speed lock-up automatic transmission used in the Mazda2 is smaller and lighter than the Skyactiv-Drive variant used in the Mazda3, Mazda6, Mazda CX-30 and Mazda CX-5. As in these models, the key requirements were strong fuel economy, a direct and engaging feel, smooth and quick shifts and prompt responses.