Lexus to return to straight-six engines

It seems Toyota and Mazda are strengthening their relationship, with a report suggesting the two will share an all-new straight-six engine in future models.

Japan’s largest automotive outlet Best Car reports that a source close to Toyota’s development group has spilled the beans on its latest collaboration, confirming Toyota will have access to Mazda’s upcoming Skyactiv-X inline six-cylinder engine.

It’s not the first we’ve heard of the straight-six Skyactiv-X mill, which went public in May this year following a leak from Mazda’s financial results. It is a larger version of the upcoming 2.0-litre four-cylinder Skyactiv-X that works similar to a diesel engine, self-combusting via compression ignition once up and running (it needs spark plugs to get going).

The 3.0-litre six will form the base of Mazda’s all-new large scale, rear-wheel-drive architecture platform, underpinning the new Mazda 6 sedan which is due around 2022 and likely to move more upmarket - at least in top model grades that will feature the more powerful motor.

Most interesting in the report from Best Car, which correctly leaked images of the Toyota Supra before the world had seen it, is that its Toyota source confirmed the company is already in partnership to use the Skyactiv-X six in its own vehicles, including premium off-shoot Lexus. Both company’s already announced a joint-production facility in the USA in June this year.

"The Mazda's straight-six engines that were revealed to go into production, were developed on the premise that they would be installed into Toyota cars,” the source said.

That would suggest funding from Toyota helped Mazda to develop the engine, a sensible idea given Mazda’s relatively small size in the automotive industry.

The ‘engines’ the Toyota source talks of are the Skyactiv-X six-pot with 48-volt hybrid and plug-in hybrid versions. The Skyactiv-X that will feature in the new Mazda3 is only 24v, the larger engine is likely to have more capabilities including a small belt or electrically-driven supercharger for added power.

But how will Toyota use the engine? While it could use it in a replacement for the Toyota Mark X - a similar car to the Camry marketed in Asian countries - it is planning to put the six into Lexus vehicles, including a possible four-door coupe.

The engine is slated for use in the Lexus IS, after its next iteration which would be around 2025. That car is already reported to come with a straight-six though the origin for an inline six, which Toyota doesn’t have, is unknown.

Toyota is also reportedly developing a ‘stretched’ version of the two-door RC coupe, according to the source, that will be positioned between it and the flagship LC - both currently powered by V8 engines - along with the LC’s V6 hybrid.

The report is not wild, as Toyota recently teamed up with Subaru and BMW to lower development costs for low-volume sports cars, including its move back to a straight-six with the new Z4-based Supra.