Our full review and technical breakdown on the all-new 2020 Mazda3 Skyactiv-X.

Mazda’s world-first Skyactiv-X engine has finally arrived in Australia, bringing a second 2.0-litre petrol option into the Mazda 3 lineup (and soon the CX-30 SUV). As far as excitement factor goes for car nerds and the mechanically interested, this is high up on the list of technology achievements to be wowing about this decade.

Its raison d’etre is to provide improved driveability and performance while reducing emissions and fuel consumption, the latter particularly important given emissions targets are becoming the norm in markets Mazda sells cars in. The way most car makers deal with this is usually by fitting a smaller turbo engine under the bonnet, or a petrol-electric hybrid. Not Mazda.

The engine is a mean feat of engineering, particularly considering Mazda is one of the smaller carmakers on a global scale. It eschewed simply turbocharging its current 2.0-litre Skyactiv-G engine and went down the route of spending a large amount of time and money developing compression ignition that ran on petrol. It also equips ‘M Hybrid’ to the SKyactiv-X in Australia, making this the only model currently available with it.  It’s not a hybrid system like you’d find in something such as the Toyota Corolla, which has a bigger (and heavier) battery and more powerful electric motor.

But all of this new technology cost comes at a price and Skyactiv-X demands a premium in the Mazda 3 lineup.

Currently, there are the 2.0L and 2.5L Skyactiv-G petrol engines available in the 3 range. The smaller, older generation engine is the entry-level powertrain on the Pure trim grade which costs $25,690 with a manual and $26,590 with the auto before on-road costs. At the top of the scale was the 2.5-litre G engine, costing $37,590/$38,950 on the flagship Astina grade depending on your choice of transmission.

Skyactiv-X is only available on the Astina grade and brings a $3000 premium. That means you can’t buy Skyactiv-X in a Mazda 3 for under $40k. Pricing is $40,590/$41,590 before on-roads with either a manual or auto. Like the others, the transmissions are both six-speed units, though the Skyactiv-X has shorter gearing (six per cent for the manual and 12 per cent for the auto).

Skyactiv-X is available on mid-tier grades overseas though Mazda tells us it isn’t currently considering doing that here. 

Otherwise, you’re looking at what is essentially the same Mazda 3 found elsewhere in the range. Being the Astina grade, it is equipped with nicer leather trim seats, heating under the pews, electric adjustment, sunroof, and dual-zone climate control. The wide infotainment screen is a winner with Apple CarPlay and Android Connectivity looking very slick; it also provides in-house apps for looking at information such as power consumption from the new M Hybrid technology.

The interior is rather nice for a small hatchback, with vision rearward and a small boot the only real compromises you pay for that sumptuous rump, though you can also get Skyactiv-X on the Mazda3 sedan, which has a larger boot and much the same everything else.

So it’s the engine then that is the star of this review, and an endeavour of Mazda that some pundits speculated years ago wouldn’t work out. It’s a complicated thing to make work.

A petrol Homogeneous Charge Compression Ignition (HCCI) engine, in theory, simulates how diesel engines operate but with petrol, wherein compression rather than spark ignites a lean fuel-air mixture. It sounds simple but many failed attempts by some of the world’s largest automakers prove its complexity, and the effective operating window is small; under load and with higher revolutions spark is required, negating fuel efficiency benefits in the sweet spot.

But Mazda has figured it out. Skyactiv-X is a compression ignition engine though it uses a spark plug, unlike the diesel design that inspired it. Mazda calls it SPCCI, or Spark Controlled Compression Ignition. The crux of the spark plug is that it can be relied upon in high-load situations but also to bring the lean air-fuel mixture to the point of instantaneous homogeneous combustion – the point where all the mixture combusts instantly at the one moment. By contrast, in a normal petrol engine, the spark plug initiates combustion in the piston chamber that moves away from spark plug and is less efficient.

Another way to think of it is that a normal combustion process is like a strip of matches lined up in row – one ignites and then quickly the other match heads ignite away from the initial spot of combustion. Compression ignition is like all the match heads in the row igniting at the same time. It results in a much faster combustion time.

The end result in a petrol engine is that the fuel mixture can be leaner and so less fuel is required, hence the engine is lighter on fuel consumption. Another particular benefit of petrol over diesel in this instance is that equivalent petrol emissions at the tailpipe are cleaner than diesel, so a petrol compression ignition cycle is desirable.

But past experiments required incredibly high compression ratios and resulted in unreliability. Mazda’s solution involves a small supercharger to compress intake air at certain RPMs and a spark plug to give the last push over the line to create instantaneous combustion at top dead centre of the compression cycle. The finer details of exactly how this is achieved as spontaneous combustion of the air-fuel mixture and not successive combustion like a spark plug would normally create are likely all in Mazda’s many patents.

What this all means in the real world is more power and torque and lower fuel consumption with lower tailpipe emissions. It also requires that you put a minimum 95 RON unleaded into the Mazda3’s 51-litre fuel tank. The quality of 91RON petroleum in Australia is horrendous compared to world standards and likely would cause issues with the SPCCI, so don’t try that one at home.

It also means that the Skyactiv-X 2.0-litre engine performs more like the 2.5-litre Skyactive-G than the 2.0L G.

On paper, Skyactiv-X with its swept 1998cc capacity across all four cylinders produces 132kW at 6000rpm and 224Nm at 3000rpm. The 2.5L produces 139kW at 6000rpm and 252Nm at 4000rpm. The 2.0L G (the older generation), creates 114kW at 6000rpm and 200Nm at 4000rpm.

Noticeable, then, is that Skyactiv-X has plenty of torque from lower in the rev range than either of the G engines. It fills what is a bit of lethargic response in the Gs so that driveability and refinement are better. The estimated 0-100km/h is around 8.0 seconds so don’t expect a substantial performance gain, but the throttle response and acceleration in traffic and on a twisting mountain road are noticeable improvements.

It’s a very nice match to the fun factor and engaging chassis the new Mazda 3 already has under its sheet metal, falling short of hot hatch territory and being nearer to warm. Again, it’s the refinement that’s the talking point and not just in how it responds to the right foot. At cruising speed, the engine is quiet and smooth, and without a coarse note when revving toward the 6500 redline.

Of note is the new M Hybrid system that uses a 24volt system with a lithium-ion battery and belt-starter motor. It doesn’t use the same size electric motor found in a hybrid that can propel at slow speeds on electricity alone, but it does bring the best stop-start system available in any Mazda due to beefed up electrical systems.

There’s no doubt that it is a very good engine and it’s a shame that the fine engineering isn’t more evident from a performance perspective. But compared to the 2.5L with its additional 7kW and 28Nm the Skyactive-X has it covered for refinement and blended ability, the lighter motor not burdening the nose, steering and front driven axles.

But we digress, the Mazda 3 Skyactiv-X is as much about being green than it is whizzing along a forested road. It is the most economical engine in the 3 lineup by Mazda’s claim: 5.3L/100km for the manual and 5.5L/100km for the auto. For reference, the 2.0L G claims 6.1L/100km, and the 2.5 G 6.5L/100km, all on the combined cycle.

For our test, we drove only the auto and on a limited urban/hills/freeway drive we were not worried about breaking fuel economy records. We hit 8.5L/100km after running about the suburbs through traffic; 11.6L/100km after driving up Mount Dandenong near Melbourne with a clear road ahead of us; and we finished the test (including suburban, hills and 15km at 100km/h) with an indicated 7.6L/100km.

That’s not bad but it’s not stellar. We’d like to see a lower fuel consumption figure and likely will with an extended test driving around different environments and on our own test routes – more to come on that one. It’s also a shame that it’s rather expensive at over $40,000 before on-roads. On the plus, its refinement and performance match expectations at that price point, and it’s undoubtedly the best pick in the 3 range, and likely for the CX-30 when that model launches too.

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