JCB has been building an unequal-wheel Fastrac, complete with stepless transmission, for over 15 years, so you would expect it to be a wellhoned machine by now. We’ve spent a couple of months living with the firm’s top dog, the 250kW/335hp Fastrac 8330, to see how it stacks up in the increasingly competitive 300hp+ sector

When it comes to a popularity contest, the 4220 is the handsdown winner in the JCB Fastrac family. So why is it, then, that the more muscular 8290 and 8330 lose out in relative sales terms in the UK and Ireland? To answer that particular question, we’ve been testing out the biggest tractor model that JCB currently builds, the 8330.

To get a feel for its in-field credentials you just need to take on board the 8330’s wheel equipment. Our unit was booted with 600/60 R38 on the front and 710/60 R42 rubber on the back (max rear wheel height is 1.95m). Compared with the equal-wheel models, the larger 8000 series should be more capable when it comes to load lugging.

8.4-litre block with Stage V credentials

Supplying the all-important propelling ponies is an 8.4-litre AGCO Power engine. Thanks to a combination of DOC, DPF and SCR, the sixcylinder motor is now fully Stage V compliant. As set out in the sleek, glossy brochure, it produces 250kW/335hp at rated speed, with a maximum output of 260kW/348hp.

As per the profi tractor testing norm we had these figures checked at the DLG test centre. According to the dyno, 199kW/266hp made it through to the pto stub at rated speed, which is 2,100rpm. This stat increased when the engine speed dropped; at 1,900rpm the dyno needle stopped at 224kW/300hp. Although this latter figure is 25kW/34hp more than the promised 10kW/13hp of extra power, it’s still 7kW/9hp less than the max pto horsepower stated in the detailed JCB brochure.

On the plus side, this power is always available, and you’re not left waiting for some form of boost to kick in when the stars line up or some other meteorological event takes place. The increase in power also resulted in a very good torque rise of 42% to 1,285Nm with just a 29% drop in engine speed.

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