Dallara secured one of the four manufacturer licences issued by the FIA and ACO to build the new generation of LMP2 cars mandated from 2017. The design bore a superficial resemblance to the Porsche 919 Hybrid and was initially tested at the Autodromo Riccardo Paletti in northern Italy, where it was spotted by the Italian motorsport press in late 2016.
The debut season exposed a fundamental aerodynamic weakness. A critical element of the sprint-configuration aero kit — later identified as the front splitter — carried over without modification into the Le Mans low-drag package, producing severe balance problems that were most apparent on the twistier sections of the Circuit de la Sarthe. The car showed strong straight-line speed on sections such as the Mulsanne Straight but lacked pace through slower corners.
For 2018 Dallara introduced an Evo upgrade package. It featured a revised splitter for the standard high-downforce configuration and a reworked low-drag kit for Le Mans. Ahead of the formal homologation of the Evo package, the revised car was tested at the Algarve International Circuit by customer team Cetilar Villorba Corse. The updated specification improved competitive parity and extended the platform's viability across all three series.
In parallel with the LMP2 programme, Dallara co-developed a Daytona Prototype International variant in partnership with General Motors and Wayne Taylor Racing, marketed under the Cadillac marque. The Cadillac DPi-V.R was powered by a 6.2-litre LS-based V8 built by ECR Engines and mated to a six-speed Xtrac transmission producing approximately 600 hp. The car was presented on 30 November 2016 and positioned as the successor to the Corvette Daytona Prototype that had competed in the Grand-Am Rolex Sports Car Series.
The DPi-V.R debuted with dominant form, winning the 2017 Rolex 24 at Daytona on its first outing with Wayne Taylor Racing heading a one-two ahead of Action Express Racing. The car went on to win eight of the ten rounds of the 2017 IMSA season. A series of Balance of Performance adjustments was applied over the season to manage the car's superiority, including mandated tall first and second gear ratios to reduce the low-end torque advantage of the naturally-aspirated V10 over turbocharged rivals. For 2018 the engine displacement was revised to 5.5 litres, again constructed by ECR Engines and producing approximately 580 hp.
In LMP2 competition the P217 recorded its only pole positions at the 2020 4 Hours of The Bend and the 2020 4 Hours of Buriram in the Asian Le Mans Series. The chassis earned strong overall results across multiple customer teams in the European Le Mans Series and FIA World Endurance Championship, while its IMSA DPi counterpart remained one of the most competitive platforms in North American endurance racing through the late 2010s.
The Dallara P217 marked Dallara's return to prototype racing and demonstrated the Italian manufacturer's ability to design a competitive customer LMP2 package. The Evo revision course — identifying the aero flaw, repackaging the splitter, and re-certifying within the homologation framework — became a reference case for mid-cycle prototype development. The DPi-V.R derivative in particular strengthened Dallara's relationship with General Motors and helped establish the Cadillac banner as a credible force in American sports car racing for the following decade.