HPD ARX-04b are rare cars with a highly unusual history. Designed and built to the then-current LMP2 regulations by Wirth Research for Honda Performance Development as the intended replacement for the hugely successful HPD ARX-03, (a series of open-topped cars that dated back to 2012) the new closed-top ‘coupe’ made its debut at the 2015 Rolex 24 Hours at Daytona.
The step into the future for the manufacturer and the Extreme Speed Motorsports (ESM) team that fielded a pair of the new cars would prove to be be short-lived though, as the 2015 season-opener would prove to be the only race that the cars would start. Both cars struggled on the Daytona banking. ESM’s #2 car for Ed Brown, Johannes Van Overbeek and Jon Fogarty would last just 49 laps before an oil pressure problem put the car out of the race. The sister #1 car for Scott Sharp, Ryan Dalziel and David Heinemeier Hansson had a rather better race. It was off the ultimate pace but at least ran well inside the top ten and was briefly scored as the leader as the leading group pitted in the early night-time running. However, the car would also fail to make the finish or sunrise, as a broken gearbox put it out of the race.
There was though a significant postscript for the cars as Michael Shank Racing was tasked with developing and preparing the cars for test purposes. The improvements made by HPD were verified by the team in testing in early 2016 before the cars were used later that same year as the principal platform for the development of the Continental tyres used for the first season of the new Gibson V8-powered cars for 2017. The cars, in fully developed form, were reported by Michael Shank to be impressive machines, with power delivery and aero performance well in line with its contemporaries.
“We tested the car twice, the first at Sebring and the second time at Road Atlanta ahead of Petit Le Mans where we were due to run our Ligier JS P2. “The test went well enough that we did actively consider switching to the HPD! We eventually decided not to, but that was a mark of how much progress had been made!”
The irony of HPD’s ‘one and out’ ARX-04b is that it is, undoubtedly, the most highly developed LMP2 of its generation.
The aerodynamics were given top-class attention to the very end of its contemporary race life. In a period when its peers were seen as life-expired, the ARX-04b was still being used as a test-bed with relevance to the future.
BBM Sport ran a further development programme in August and September of 2023, where the car proved to be faster than any other LMP2 cars that raced at the 2023 Silverstone Classic by recording a 1m45.8 around the GP track. There are two cars available: 1 of them is totally rebuilt with new engine, gearbox, fuel tank, belts, extinguisher and more. The other car is 70% complete, with a new engine and gearbox, but needs additional body work. There’s also a huge spares package – too numerous to list.
