The Acura ARX-01 (sometimes referred to as simply the Acura ARX) is a Le Mans Prototype built for sports car racing, specifically in the American Le Mans Series. It is the first purpose-built race car by the Acura division of Honda Motor Company, part of their multi-year program to eventually compete in the 24 Hours of Le Mans endurance race. Two of the three Acura teams, Highcroft Racing and Andretti Green Racing, initially used the ARX-01a in 2007, while Lowe's Fernandez Racing used a Lola chassis with the Acura engine. In 2008, an upgraded ARX-01b was introduced for all teams, with the addition of a fourth team run by Gil de Ferran.
At the 2006 North American International Auto Show, Acura officially announced their plans to develop a Le Mans Prototype program for the American Le Mans Series, competing in the LMP2 class for the initial year of competition in 2007. Acura announced they'd be using customer chassis from Lola Cars International of the United Kingdom and Courage Compétition of France, while the engine would be built entirely by Honda Performance Development of the United States. Acura planned to use the customer chassis for the first year, then to build their own chassis for 2008, followed by another new chassis for a move to the top LMP1 class in 2009. At the auto show, Acura showed their first customer chassis, a brand new Courage LC75.
Following the announcement of the three teams involved in the project, Acura announced that for 2007 each team would concentrate on a certain aspect of development for the planned 2008 car. Andretti Green Racing and Highcroft Racing would use Courage LC75 chassis, and work on chassis design and aerodynamic modification. The third team, Fernández Racing, would use a Lola chassis and concentrate on developing the new Acura V8 engine. A third Courage LC75 would be retained by Honda of America for use as a developmental prototype.
By early 2007, all three teams had begun testing their cars as well as beginning modification. By the time the American Le Mans Series opening round at the 12 Hours of Sebring arrived, the two Courage LC75 teams had modified their chassis to such an extent that Acura applied for homologation from the International Motor Sports Association (IMSA) and Automobile Club de l'Ouest (ACO). With the application approved, the Acura Courage LC75s were renamed as Acura ARX-01a.
As for the engine, Honda Performance Development created a new 3.4 Liter V8, the maximum size allowed by the rules, the first V8 ever branded as an Acura as well as the first motor built entirely in the United States by Honda. Elements of the Acura V8, dubbed the AL7R, share similar architecture with the Honda engine used in the Indy Racing League although none of the parts are interchangeable.
The two new Acura ARX-01as, along with the other Lola team car, debuted at the 2007 12 Hours of Sebring after much preparation. Battling not only the Porsche squads in their own class, they also attempted to compete with the Audi R10 diesels in the higher LMP1 class throughout the race. During the race the ARX-01a showed the ability to at least keep close to the Audi, yet was unable to truly fight for the lead. However, in the end the Acura ARX-01a of Andretti Green Racing was able to survive the race better than other competitors and managed to take the class victory, as well as second place overall. The second ARX-01a of Highcroft Racing took sixth place overall, while the Acura-powered Lola of Fernández Racing took third.
On July 12, 2008, the #9 Patrón Highcroft Racing ARX-01 earned Acura's first-ever overall victory in the American Le Mans Series. David Brabham and Scott Sharp started the Highcroft entry from pole, and managed to retake the lead from the #7 Penske Racing Porsche RS Spyder in the final 90 seconds of the Northeast Grand Prix. This was followed by a second overall win at the Detroit Sports Car Challenge, this time led by Andretti Green Racing's Franck Montagny and James Rossiter.
The Acura ARX-01b won six of the eleven races in the LMP2 class for 2008, with four for Highcroft and two for Andretti Green. Highcroft was ranked second in the Teams Championship, Andretti Green fourth, Fernandez fifth, and de Ferran sixth. Acura lost the LMP2 consturctors championship to Porsche by a single point.