JCB Hydromax hits 368mph at Bonneville

PH was there to see JCB, Prodrive and Andy Green score big at Bonneville Speed Week

You’re looking at the world’s fastest hydrogen car. At least by the standards of the Southern California Timing Association – the folks clutching the stopwatches at Bonneville Speed Week. The JCB Hydromax has hit the first of its targets, averaging 368.347mph over two runs to beat its Dieselmax predecessor of 2006. PH was on the salt to witness it.

Quite a thing the Hydromax is to witness merely stood still. Its 9.75m length is made up of a carbon monocoque, steel tubular frame and carbon panels. There’s a pair of JCB’s latest, site-proven hydrogen combustion engines, both within the wheelbase and each possessing 4.8 litres, four cylinders and 800hp – ten times their standard output thanks to Ricardo.

Each engine takes independent care of an axle (for four-wheel drive) and has its own six-speed Xtrac sequential ‘box; a clever ECU ties both powertrains together so that driver Andy Green – of 763mph Thrust SSC Land Speed Record fame – only tugs one set of paddles. There are real, physical brakes to back up the twin parachutes and there’s no clutch to worry about. Andy opts not to left-foot brake. Though its silhouette isn’t a million miles from the dozen or so homegrown Streamliners it shares the salt with at Speed Week, the Hydromax is notably bigger and heavier, weighing in at around 2.5 tonnes.

While it claims 1,600hp and 2,200lb ft, for Speed Week duties its engines have run at three-quarters of their peak. After initial tests at RAF Wittering, this first week on the salt has been a gradual build up towards FIA-sanctioned runs when the engines will be at full hilt.

Andy Green was on driving duties in 2006 when the JCB Dieselmax set a still-standing 350.092mph record for its own fuel at Bonneville. The Hydromax is essentially a reboot – albeit a comprehensive one.

“The only things that are the same are their tyre pressure valves, because they're the only ones rated to 350mph-plus, and their driver,” smiles Andy. “Everything else is different. The car is lighter, slipperier, more powerful and cleaner.”

It’s now a Prodrive effort, too, the Banbury firm adding Land Speed Record-chasing to its vast repertoire. Its Dakar endeavours have perhaps surely proved an especially useful barometer in handling Utah’s 40-plus degree heat with little more than a gazebo for shade.

Wing Commander Green is also first to admit that a pair of digger engines solidly mounted to a carbon monocoque creates quite a rattly environment, one not helped by the changing surfaces of the Bonneville Salt Flats.

“It can be a disorientating environment,” he tells PH. “But I'm utilising skills that are anchored in 30 years of having the world's best day job as a Royal Air Force fighter pilot. I also spend a few minutes before I get in the car watching another couple of cars go down the track. You can learn a lot. If there's not much salt spray, the grip's probably quite good. You then watch the car drive off into the distance: one mile, two miles. By mile three it's disappearing. The curvature of the earth here is a real thing because you can watch cars disappear over the horizon.”

There are two places to watch Andy and JCB do their thing. From the start line, you see not only the pageantry of Speed Week play out, but the incongruity of a big budget effort like this rolling among the bizarre homebrews. 2026’s efforts range from a lightly modified Suzuki Cappuccino to terrifyingly slim, belly-scraping missiles.

Hydromax, like most cars here, doesn’t project itself from the line. Prodrive-stalwart Darren Turner instead shoves it up to 60mph with the might of a Defender Octa, at which point first gear engages, the Landie drops away, and Andy’s right foot is flat to the floor until he’s nudged his run’s target speed and it’s time to pull the ‘chute.

The alternative is to station yourself a safe distance back from the mile four markerboards to see the yellow ‘n’ black cigar dissect the sky and salt in one smooth, grumbly motion, the industrial sound of its powerplant oh so slightly lagging the visual. Astonishing stuff. JCB’s big budget arrival on the Salt Flats has proved an amiable one, too. The locals and regulars love the recognition it brings their event, while the JCB team have a thriving community around them in support. Andy’s impressed, too.

“One of the cars out here last year [during a Prodrive event recce] was running in the seven to eight litre class. They then decided to modify their car to run in the six to seven litre class, which they did by taking a piston out and putting a balance weight on the crankshaft. The engine was still nice and balanced, now running on seven cylinders instead of eight. What a genius solution for putting yourself in a different class with half a day's engineering work.

“That's not something you see anywhere else in the world. Here at Bonneville there’s lateral thinking, innovation and creativity to work out how to break records in your particular class. It's hugely exciting to be part of that community and to share both ideas and the excitement of Land Speed Record racing.”

JCB’s journey isn’t over yet. Early next week, the FIA adjudicators descend on the salt to scrutinise the Hydromax on a longer course and running in opposing directions – the wick of its engines fully turned up. PH is sticking around in Utah to hopefully witness that, too.

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Noe

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