VIDEO: A behind the scenes look at how JCB set the new British tractor speed record

Having been involved in several record attempts, including fastest speed on a gravity-powered snow sled, fastest speed in a soapbox and highest speed on a wall of death, Guy was the ideal candidate to take on the challenge.

Like many of his endeavours, Guy’s involvement will be aired on TV later this year, which follows him and JCB throughout the tractor’s development, taking in design, manufacturing and testing processes.

While by its very nature the standard Fastrac is a fast tractor (up to 50mph depending on markets), it has taken quite a few modifications to get it to the top side of 100mph. Size-wise it is based on a Fastrac 4000 Series, but draws upon the heavier-duty components of the 8000, as well as parts and expertise throughout JCB.

Having worked on the DieselMax world record in 2006, JCB’s group director of powertrains, Alan Tolley talks us through the finer details of the tractor.

• Engine: Needing more power, the firm replaced the stock tractor’s AgcoPower engine with its own six-cylinder, 7.2-litre, DieselMax motor. Capable of 1,000hp and revving up to 3,800rpm, maximum torque is delivered between 2,000 and 3,000rpm. Fitted with an enlarged turbo, extra boost, particularly for gear changes, comes in the form of an electrically-driven supercharger. Running on normal diesel, expert tuning comes courtesy of Ricardo, which sees a large common rail fuel injection system from Delphi added. Amazingly, all castings; block, crank, head and pistons are standard. And no it does not meet Stage 5 emissions regulations.
• Cooling and airflow: Cooling and packaging was a massive challenge for the engineers, which sees radiator cores relocated into side pods – much like a formula one car. This leaves room for three massive air scoops at the front of the engine to feed the hungry turbo and super chargers and keep the engine’s viscous damper cool. On top of this, Denso created a bespoke water to air charge cooler, located in the nose of the tractor.
• Transmission: Though it would have provided seamless speed transitions, the Fendt-derived continuously variable transmission would not be up to the speeds involved, which sees a six-speed ZF truck gearbox fitted - though four were only used! Connecting the engine and gearbox is JCB’s own multi-plate wet clutch.
• Aerodynamics: With the aid of Williams Advanced Engineering, drag of the tractor has been reduced by a quarter. To achieve this a specially built aero kit as to be designed. In addition, the cab is lower and narrower, and along with narrower tyres, this helps to reduce the tractor’s frontal area.
• Weight: Excess weight is a speed killer, and as such the Fastrac was put on an extreme diet which sees about 40 per cent of its weight shed. Particularly from the chassis, which was designed to carry out heavy draft work, much of its strength could be taken out. Similarly, there is no need for hydraulics, link arms or a PTO.
• Axles: Similar to the shape of a truck axle, the front axle’s ‘U’ profile allows the tractor to be lowered, making it more stable at high speed. It is only rear wheel drive too, avoiding parasitic losses. To maintain straight line stability, the rear axle has no differential, just a solid spool, adapted to handle the power and torque.
• Brakes: Though the tractor is travelling much faster than normal, because of its reduced weight, the brakes are pretty much standard. However, to reduce weight and power requirements, the air compressor has been removed, with three pre-charged air tanks used instead.
• Tyres: Supplied by BKT, tyres are more of an industrial heavy-duty type with a block tread pattern. However, a tailored compound was used to make the tyres, which were also ‘shaved’ to reduce any unnecessary weight.
• Cab: taking inspiration from the truck racing world, inside the tractor has more of a racing feel, with minimal controls, racing seat, six-point harness, removable steering wheel and full roll cage. All glass is replaced with polycarbonate material.
• The result: Mr Tolley explains; “Despite being focused on creating a faster version of the Fastrac, many valuable things were learnt during the development process, such as air flow, the importance of ride height management, aerodynamics and stability. This then starts to open up future possibilities.”