The earth-mover marque is attempting to break the diesel land speed record. John Simister reports on a very British projectThe land speed record. Fastest human on earth. Glory and pride and a lot of danger. Currently it stands at a supersonic 763mph, set in 1997 by a virtual jet aeroplane with no wings and bigger wheels.
In August, if all goes to plan, the record will hurtle to more than 300mph. And the vehicle to do it will be a JCB.
The JCB Dieselmax, a 9m-long streamliner powered by two highly tuned examples of the JCB444 diesel engine that has powered all kinds of JCB machinery since 2004, is, however, different from your usual digger.
The JCB444 engine – four cylinders, 4.4 litres, designed by the British engineering consultancy Ricardo – comes in many forms to suit its different applications. Normal outputs of the 16-valve turbodiesel are up to 125bhp and 457lb ft of torque with a speed limit of 2,800rpm, but the Dieselmax clearly needs much more than that to break the 300mph barrier. So the capacity is increased to 5.0 litres, and it gains modified pistons, camshafts and fuel injection to increase the flow of fuel and air.
Both an intercooler and aftercooler help to make the intake air denser, and water injection and extra oil jets keep things cool when the two-stage turbocharger is blowing at its maximum 5.2 bar boost (more than turbocharged Formula 1 cars used to have).
The result is an engine with 750bhp, 1,105lb ft of torque, a rev limit of 3,800rpm and an appetite for only the very best high-cetane diesel fuel. And the JCB Dieselmax has two of them. One drives the front wheels, the other the rear wheels, and the driver sits between them. There are two gearboxes as well, linked electronically so there’s no danger of one changing gear when the other does not.
Continues at [motoring.independent.co.uk] – see also JCB DieselMax, notably [www.gizmowatch.com] for pictures.
Redline at 3800rpm. Dearie dearie me.
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