TWO ADDITIONS to John Deere’s W series straw walker combine line-up have been created largely by installing more powerful engines to extract more performance from the threshing and separation systems, especially in difficult harvesting conditions.

The five-walker W550 comes in with a 35hp advantage over the W540 model – its 6.8-litre six-cylinder develops 290hp peak out. Similarly, at 350hp from its 9.0-litre diesel, the six-walker W660 newcomer has an extra 32hp over the 318hp W650.

That means growers happy with the performance of a simple walker-separation harvester now have two models to choose between in the five and six-walker class – with the further choice of a bigger grain tank than the standard offering. W550 buyers can choose a 10,000 litre tank over the 8000 litre version and, on the W660, 11,000 litres instead of 9000 litres.

That applies regardless of the whether the combine comes in standard level-land or HillMaster format – the latter having a self-levelling chassis and baffled sieves to keep loading evenly across slopes up to 22% – or the electronics installed.

The ‘i’ package comprises automatic forward speed adjustment according to cylinder load and GPS-guided automatic steering (plus HarvestDoc recording software), which together are said to give a 23% advantage over standard models.

In addition, the W660i can also have Deere’s new ProDrive automatic hydro transmission, which is designed to keep the machine on the move more efficiently, especially when working on hilly ground, in difficult harvesting conditions or travelling on the road.

The performance advantage of the extra engine power is evident from the recommended cutting table widths – 6.1m verses 5.5m for the W550 over the W540 and 7.6m for the W660 against 6.1m for the W650.