DRIVING IMPRESSION: Agritechnica 2013 saw the arrival of Challenger’s E-series crawlers. With either seven or 12 cylinders and from 378hp to 637hp on boost, these are some mighty bits of kit — and prior to the show we drove one. Check out our review of the latest MTs to hit the market
Until last November, Challenger’s UK tractor line topped out at the MT875C. On boost, its engine delivered 454kW/609hp from six cylinders and met previous emission requirements: but times move on. Now Stage IV is the hurdle to jump and Caterpillar’s C18 powerplant has to go. In its place steps an AGCO unit — the 12-cylinder AP168-4.
Switching to a big V12 doesn’t mean more cubic capacity. Quite the reverse, as engine displacement reduces from the C18’s 18.1 litres to ‘just’ 16.8 litres. The important factor here is that individual cylinder capacity is halved, and smaller cylinders give more leeway for combustion improvement. Power freaks need not despair, though — two turbos for each cylinder bank nudge the new engine’s maximum torque up a fraction to 2,840Nm at 1,500rpm (100rpm higher than the old engine), while rated and maximum powers grow: the new values are 440kW/590hp and 475kW/637hp, against the previous 425kW/570hp and 454kW/609hp. The AGCO Power engine uses electronic fan speed control and packs almost
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