How fuel efficient is the Mazda CX-90 diesel? New straight-six bests CX-8 in official figures

The upcoming Mazda CX-90 SUV is more fuel efficient in turbo-diesel six guise than the diesel CX-8 currently on sale

Mazda Australia has released fuel efficiency figures for its upcoming CX-90 large SUV with its new straight-six diesel engine.

The new 3.3-litre ‘D50e’ engine is said to use just 5.4L/100km in the CX-90, slightly more than the 4.9L/100km rating of the smaller CX-60 midsize SUV which also uses this engine.

Compared to Mazda’s smallest seven-seater, the CX-8, the CX-90 uses 10 percent less fuel than the former’s 6.0L/100km figure despite using a smaller 2.2-litre turbo-diesel four-cylinder engine.

2023 Mazda CX-90 cutaway chassis picture — Underneath the skin of the new Mazda CX-90

While official weight figures have yet to be released for the CX-90 in Australia, Mazda’s new SUV is larger, wider and expected to be slightly heavier than the CX-8 which has a kerb weight of 1931kg in entry-level Sport guise.

Mazda will use its new CX-90 to target key rivals in the premium SUV space such as the Volvo XC90 and Audi Q7 but also offer lower fuel economy when compared to other hybrid SUVs such as the Toyota Kluger with its 5.6L/100km combined figure.

The 3.3-litre turbo-diesel six produces outputs of 187kW/550Nm, a boost in performance when compared to the 140kW/450Nm of the smaller 2.2-litre twin-turbo-diesel engine.

2023 Mazda CX-90 cutaway picture — The Mazda CX-90 is likely to compete with cars such as the Volvo XC90 and Audi Q7

Mazda says it has achieved its low-5L fuel consumption figure by using surplus air to aid acceleration response, lower nitrous oxide emissions and improve thermal efficiency.

The new Mazda CX-90 will go on sale in Australia during the third quarter of 2023, with further pricing and specification to become available during the first quarter of 2023.

Which other powertrains are available for the new CX-90?

An identical displacement 3.3-litre petrol straight-six engine will also be available for the upcoming CX-90. This unit will make 254kW/500Nm – very similar outputs to BMW’s current B58 3.0-litre turbo straight-six.

2023 Mazda CX-90 cutaway chassis and powertrain — Mazda has made its new straight-six engines remarkably fuel efficient

Mazda says this powertrain is the most powerful production engine made by Mazda to date.

To compare, the new turbo-petrol straight-six powertrain makes 50 percent more power and 19 percent more torque than the current CX-9’s 2.5-litre four-cylinder petrol engine.

Fuel efficiency for the 3.3-litre turbo-petrol engine is rated at 8.2L/100km, which Mazda says is an improvement of almost 10 percent when compared to the CX-9’s petrol unit.

2023 Mazda CX-90 interior wide shot — A look inside the cabin of the new 2023 Mazda CX-90

Mazda says fuel efficiency has also been boosted thanks to both petrol and diesel straight-six engines incorporating a 48-volt mild hybrid system that sees an electric motor supplement the combustion engine at certain points during driving.

A plug-in hybrid variant has been confirmed for the US market, however it has not been locked in for Australia. However, the smaller CX-60 SUV will come to Australia with a plug-in hybrid option.