The new SkyActiv-X engine certainly creates the most convincing version of the new Mazda 3 yet, but it feels in some ways that the clever spark controlled compression ignition technology under the bonnet is being held back from its ultimate potential. This is the very first application of the tech though, so it’ll only get better with time. Here and now you get some much needed extra power over the SkyActiv-G car without really sacrificing fuel economy, but a little refinement is lost. It’s good enough to be our pick of the Mazda 3 bunch. SkyActiv-X is a brand new, spark controlled compression ignition (SPCCI) engine that has been under development at Mazda since 2015. The firm proudly insists that it’s the first true compression ignition petrol powered engine ready for production. It’s a petrol engine that uses intense pressure to combust the fuel-air mixture, like you would find in a diesel engine. Spark plugs remain in place as a control factor, but in the simplest terms, the aim is petrol performance and responsiveness with diesel fuel economy. The engine makes its debut here in the latest Mazda 3 - a car we’ve already heaped plenty of praise on for its style, upmarket quality, strong levels of refinement and, more than anything else, for the way it drives. It’s a brilliant family hatchback to find yourself behind the wheel of, but the car’s launch engines lacked a little sparkle. That’s a gap Mazda hopes the new engine can bridge when it lands in the UK this October.

As the revs rise the engine note changes too. From a petrol-like idle the sound begins to mimic a diesel knock when the engine is turning over around that 3,000rpm peak torque zone, then the sound transforms back to a smoother petrol note as you get into the higher reaches of the rev band. A menu on the slick infotainment system can show you when the car is operating in SPCCI mode, and it shows that there really isn’t a certain speed or rev zone required to achieve this - just keep the car at a steady pace and eventually it’ll settle back into performing its party trick. What does that mean for fuel economy? In the manual car we threw caution to the wind to try and unpick the secrets of the new engine, only averaging 28mpg but making full use of the derestricted autobahn on our test route. A more realistic drive in an automatic SkyActiv-X equipped 3 threw up 40mpg on the trip computer, so stick with the excellent six-speed manual gearbox and 40+ without really trying is probably what you’re looking at. 17 Does that really move the game on from the turbocharged opposition? Not really, based on our first, somewhat unscientific taste of the technology. It seems as if the SkyActiv-X car won’t be hugely more economical to run than the cheaper SkyActiv-G either. But, importantly, it is a much better performer, and almost certainly the car to budget for. The more powerful engine loses a little refinement, but finally the Mazda 3’s excellent chassis and steering have a whiff of performance to exploit.