Where the THL1 had been adapted to accept a Hart straight-four as a stopgap, the THL2 was designed from the outset for the turbocharged Cosworth GBA, marketed as the Ford TEC V6. The engine produced around 900 bhp, a substantial improvement over the Hart unit but significantly short of the 1,300-plus bhp reported from the Renault V6s in the Lotus and the 1,400 bhp available from the BMW four-cylinder engines used by Benetton and Arrows.
Two young aerodynamicists worked extensively on the car's wind tunnel programme alongside lead designer Oatley: Ross Brawn and Adrian Newey. Both would go on to become defining figures in Formula One engineering. The resulting car was widely regarded by drivers and observers as among the best-handling chassis of the 1986 season, with its primary competitive deficit being straight-line speed on power circuits.
One design detail that 1980 World Champion Alan Jones found frustrating was the turbo boost control: two knobs protruding from either side of the dashboard that required the driver to take a hand off the steering wheel to adjust boost pressure, unlike Williams and McLaren cars whose boost controls were mounted on the steering wheel hub.
The THL2 debuted at the San Marino Grand Prix at Imola, driven by Jones. Patrick Tambay, who had won two Grands Prix for Ferrari in 1982 and 1983 before two seasons with Renault, joined as the second driver. Tambay received his THL2 at Monaco, qualifying eighth before crashing in the closing laps when his car rode over Martin Brundle's Tyrrell and flipped at Mirabeau.
The team's best qualifying performance came from Tambay, who placed sixth on the grid for the Hungarian Grand Prix at the Hungaroring, a new circuit whose tight and technical layout rewarded handling over raw power. The tight nature of the Hungaroring allowed both drivers to be competitive in a way that power circuits did not.
The season's highlight was the Austrian Grand Prix at the Österreichring, where mechanical failures for several front-running teams allowed the Haas entries to score championship points. Jones finished fourth, earning three points, and Tambay finished fifth for two points. Despite the Österreichring normally favouring outright power — where the Ford V6 was at a disadvantage — a slipping clutch on Jones's car paradoxically helped by reducing wheelspin, and Jones was the only top finisher to run the entire race without a tyre stop, albeit finishing two laps behind race winner Alain Prost's McLaren-TAG.
Jones also scored a sixth-place point at the Italian Grand Prix at Monza. At the German Grand Prix both cars finished for the first time, with Tambay classified eighth and Jones ninth. The team's points total for the season was five.
Driver requests for special qualifying engines — common practice among the leading teams to extract additional power for grid-position laps — were consistently refused by Keith Duckworth, Ford and Cosworth, who believed their proven reliability record was sufficient compensation. Jones highlighted the disparity at Monza, noting that the slowest competitor using a V6 Ferrari was still approximately 20 km/h faster in a straight line than the Lola Fords running minimal wing settings, and that the team was in fact slower at the speed trap than the under-resourced four-cylinder Zakspeed cars.
The THL2 ended its competitive life at the Australian Grand Prix, where Jones retired and Tambay finished but was not classified due to being lapped too many times. The withdrawal of Beatrice Foods' sponsorship, which had been progressively reduced since mid-season following a management change at the company in late 1985, made it impossible for the team to continue. Both Jones and Tambay retired from Formula One after 1986.
The THL2 stands as an illustration of how chassis quality alone cannot overcome a fundamental power deficit in a turbo era dominated by manufacturers with vastly greater engine development resources. Its two principal aerodynamicists, Brawn and Newey, would later design cars that dominated Formula One for decades.