Nine is enough for ZF

Land Rover's application of a nine-speed automatic gearbox in the revised Evoque launched at the Geneva motor show is a world first. But the new gearbox's number of ratios was driven by design, not fashion.

ZF insiders interviewed by motoring.com.au at the Swiss show said there were two key parameters for the design of the gearbox. Firstly, to fit in 360mm space once occupied by an Aisin-supplied six-speed auto, and, equally critical, to deliver a significantly wider set of gear ratios.

When ZF's designers set about designing the autobox the ability to stack three clutches and three planetary gear sets meant the nine-speeder proved more compact and lighter than proposed seven and eight-speed solutions. As a consequence the new gearbox is also around 7.5kg lighter than the six-speeder it replaces.

The new gearbox has a ratio spread of 9.81:1, more than 50 per cent 'wider' than the old Evoque gearbox (6.1:1).

In the case of the baby Rangie, this means the offroad icon can deliver a lower crawler-style first gear for better hill climbing and descent and still pack highly overdriven high gears for open road fuel economy. The multi-gears can also better cope with the narrower powerbands of higher performance turbo-diesel engines.

In the Evoque installation, the engine and transmission control units are calibrated to allow the car to start in second and even third gear.

Land Rover claims fuel economy benefits of around 10 per cent in rolling road ECE testing combined with auto stop-start. In real world testing ZF has delivered reductions of between 10 and 16 per cent.

And despite its compact size, the gearbox is no shrinking violet. It is rated to a torque loading of 480Nm.

The new box is designed to fit the Evoque's transverse engine location and is therefore equally suited to pure front-drive applications. Our ZF boffins confirmed three other manufacturers would shortly announce their plans for the new gearbox.

The move to nine speeds in the new box does not mean the German transmission specialist will scrap its eight-speed longitudinal box any time soon, however. Say the ZF boffins, the existing eight-speeder (used in a range of BMWs, Audis, Jaguars and Land/Range Rover models) is just a few years into a lifespan that could stretch to a decade or more.

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