Mazda CX-30 X20 Astina 2021 Review

Mazda has done what some other car-makers have deemed almost impossible by creating a petrol engine that works in much the same way as a diesel. Adding to the intrigue, the SKYACTIV-X engine is also hybridised and supercharged.

We first heard of Mazda’s SKYACTIV-X compression-ignition petrol engine in late 2017, when company execs announced that the technology would appear on production models by early 2019.

They were pretty much spot on. In July 2019, well before the world stumbled into the COVID-19 pandemic, the international motoring press was sampling the ground-breaking new technology which was slated for Australian introduction later in the same year.

And did it sound promising. Using the principles of diesel-style compression-ignition in petrol-fed form, the technology aimed to combine the high-rpm performance of the former with the fuel efficiency of the latter – without the clatter.

Using what Mazda calls Spark Controlled Compression Ignition (SPCCI), the system’s diesel similarities come into play as ignition is mainly initiated not by a spark plug, but by combustion chamber pressure. The big difference is that the fuel is petrol and that spark plugs are actually used – briefly – during some parts of the process when compression-ignition can fall short, such as when the engine is being fired up from cold or running at the top of the rpm range.

Less of a conceptual difference, but separating it from current diesels nonetheless, is the
SKYACTIV-X engine’s use of supercharging, not turbocharging, to help torque production in the mid-rpm range.

And as if that isn’t enough, Mazda added very-mild hybrid technology into the mix, making for an intriguing new spin on how best to design and make an efficient reciprocating internal combustion engine.

The SKYACTIV-X engine first came to Australia as an option in the Mazda3 Astina in mid-2020, followed by the Mazda CX-30 X20 Astina small SUV on test here.

Of course, the SKYACTIV-X engine makes for an expensive Mazda CX-30 (or Mazda3).

So this ground-breaking version on test, the 2021 Mazda CX-30 X20 Astina, is tagged at $47,090 plus on-road costs, which is about as big an ask as you are likely to find among volume-selling internal combustion small SUVs.

Like the more normally-engineered CX-30s, the SKYACTIV-X wants for little. There’s as full a bag of safety technology as you are likely to find, including high- and low-speed autonomous emergency braking (AEB), reverse AEB, adaptive cruise control, pedestrian avoidance, lane departure warning, lane keep assist, blind spot monitoring, front and rear cross traffic alert, driver attention detection, front, side and rear cameras and front and rear parking sensors.

Along with seven airbags and all the familiar safety and vehicle stability aids including stability control, anti-lock braking and traction control, the CX-30 also gets G-Vectoring control which, through manipulation of engine torque to shift the vehicle’s weight balance around corners, helps stabilise the handling.

The big question is whether the added $3000 on top of the already-pricey Mazda CX-30 G25 Astina – positioned at $44,090 plus ORCs – is justified.

If you are asked to pay an extra three grand on top of an expensive small SUV that pushes close to $50,000 by the time you get it on the road, you’d expect to be able to justify it, right?

There’s no doubt that the funds Mazda has invested getting SKYACTIV-X technology to work effectively have resulted in something with a whiff of specialness about it. The promise of its being 30 per cent more efficient than a regular engine is incentivising in itself, as is the lure of supercharging and hybridising.

So what does all that mean in regular, day-to-day use?

Compared to the normally-aspirated 139kW/252Nm 2.5-litre petrol engine that’s used in the G25 CX-30 Astina, the 2.0-litre SKYACTIV-X in the 2021 Mazda CX-30 X20 Astina outputs 132kW at 6000rpm and 224Nm at 3000rpm. So it’s less powerful but claims to be more economical.

That’s the claim anyway. Though the official figures say 6.0L/100km on the combined test cycle, we recorded, in generally benign circumstances, 7.6L/100km – a figure you could imagine coming close to in a regular AWD G25 Astina (for which Mazda claims 6.8L/100km).

It’s worth noting that the SKYACTIV-X figures are well short of hybrid competitors such as the Toyota C-HR (4.3L/100km), marginally better than the Subaru XV mild-hybrid (6.5L/100km) and quite a bit behind the premium Lexus UX hybrid’s claim of 4.5L/100km.

The SKYACTIV-X CX-30’s emissions – touted as a big incentive in developing the technology – aren’t noteworthy compared to some regular hybrids either.

The 141g/km CO2 output on the CX-30 SKYACTIV-X is much higher than the Toyota C-HR’s 97g/km and the bigger-engined Lexus UX’s 103g/km, and is close to on par with the Subaru XV hybrid’s 147g/km. The Mazda needs to be hooked up to a 95-otane fuel pump too (although E10 is okay).

The bottom line is that, if the SKYACTIV-X is 30 per cent more efficient than a regular petrol engine as claimed, it’s hard, in real time, to see the evidence.

Likewise the performance. If we were expecting a surging thrust helped by the supercharger that’s also part of the engine package, that’s lacking too.

The conventional 2.5-litre G25 CX-30 offers a better power-to-weight ratio than the SKYACTIV-X version – and is consequently more accelerative – for what seems only a slight shortfall in fuel economy and exhaust emissions.

To drive, the X20 CX-30 feels like a normally-aspirated 2.0-litre. It lacks the mid-range muscle that usually accompanies forced induction and it’s not especially quiet either as it builds rpm – despite the full under-bonnet noise-reducing shielding – with a not especially appealing roar from the engine bay.

This prompts the question: Why?

A big part of the SKYACTIV-X CX-30 X20’s underwhelming road performance can be traced to the ultra-mild hybrid set-up.

The 24V lithium-ion battery pack, located under the right-side floor of the CX-30, is pretty small and is charged only through regenerative braking.

The hybrid drive comprises a small electric motor that gives some support to the engine while also acting as a starter motor. The hybrid battery powers the electrical ancillaries when the engine is stopped.

The funny thing about all this is that you tend to forget the real story – the clever compression-ignition technology that’s working away undetected deep within the SKYACTIV-X.

It fires up like a conventional petrol engine, sounds like any other petrol engine and gives no audible clue when switching from spark-induced to compression-induced combustion.

This, rather than the mild-hybrid functions, is what makes the engine special.

The Mazda CX-30 is already an appealing small SUV with a good balance of style, quality, space, functionality and road performance. That was underscored by its outstanding performance in carsales’ Best Small SUV 2021 mega-test.

But in this guise, the top-shelf CX-30 offers a promise of slightly better economy and lower exhaust emissions for a price some would baulk at.

The 2021 Mazda CX-30 X20 Astina will appeal to early adopters unfazed by cutting-edge technology that, in real life, offers minimal returns for a (relatively) big investment.

It’s bordering on radical, but to what end?

Mazda’s view is that the improved petrol engine efficiency provided by technology such as SKYACTIV-X will play a part in filling the time gap between conventional fossil-fuel engines and widespread electrification.

Laudable aims, but have they been realised?

The gains made in the hard-fought battle to perfect the petrol combustion-ignition process that have been denied other car-makers would appear, at this stage, so small that you would have to question the development cost benefits.

In the end, the minimally-effective petrol-electric function raises the question of whether the Mazda CX-30 SKYACTIV-X is not so much a hybrid as a whybrid.

How much does the 2021 Mazda CX-30 X20 Astina cost?
Price: $47,090 (plus on-road costs)
Available: Now
Engine: 2.0-litre four-cylinder supercharged petrol
Output: 132kW/224Nm
Transmission: Six-speed automatic
Fuel: 6.0L/100km (ADR Combined)
CO2: 141g/km (ADR Combined)
Safety rating: Five-star (ANCAP 2019)

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