IMSA, WEC follow different paths to common power cap

Image by Joe Portlock/Motorsport Images

IMSA, WEC follow different paths to common power cap


IMSA, WEC follow different paths to common power cap


The final piece of the regulatory puzzle for IMSA’s new-for-2022 LMDh prototype formula, and the technical compromises meant to bring LMDh and the FIA WEC’s new Hypercar formula together on track have been formally released by both organizations.

As RACER revealed on Wednesday, the key areas of agreement between IMSA, the WEC, and the ACO, which runs the 24 Hours of Le Mans, involves setting a common power cap of 670hp for Hypercar and LMDh. The methods of how that peak 670hp figure is reached vary in significant ways across the two categories.

In Hypercar, internal combustion engines (ICE) are mandatory, but kinetic energy recovery systems (KERS) are not, leaving manufacturers with the ability to produce the 670hp with one or both powerplant options installed. Hypercar adds another variable with the allowance for KERS installation on the front or rear axle, which makes it possible for all-wheel-drive solutions in the WEC’s formula, and a higher power KERS system can be used, which would ask less of the ICE to reach 670hp, if that route is chosen.

In LMDh, ICE and KERS are mandatory, with the spec KERS unit said to be responsible for approximately 40hp in the 670hp sum. Dissimilar to Hypercar, IMSA’s new KERS solution is only allowed to drive the rear axles, eliminating all-wheel-drive as an option.

Although it was left undefined in the newest release, it’s believed heavy usage restrictions will be implemented for Hypercars with KERS units driving the front wheels, done in an effort to minimize the advantages all-wheel-drive is known to deliver in acceleration, cornering, and braking against two-wheel-drive cars like those conforming to IMSA’s LMDh regulations.

The 670hp cap is a significant downward adjustment from the 785hp Hypercar manufacturers were working from for quite some time. The 115hp reduction will allow IMSA’s current DPi manufacturers to carryover their existing ICE solutions to LMDh, if desired.

The convergence regulations appeared aimed at pointing low-volume auto manufacturers toward the Hypercar category rather than LMDh prototypes. Image by Rainier Ehrhardt / LAT Images)

An interesting point of clarity was offered on the type of auto manufacturers that will be welcomed into LMDh, as “mainstream” was used to describe those brands who will be accepted into the formula that relies on four LMP2 chassis suppliers to provide the underlying cars that will carry engines and custom bodywork from those manufacturers.

It suggests the Hypercar formula, which openly invites non-mainstream manufacturers, would be the only route for low-volume brands to follow in order to compete in the converged WEC and IMSA opportunities coming in 2022. It could also imply low-volume Hypercar manufacturers might face obstacles in gaining access to future IMSA entry lists comprised of mainstream auto manufacturers.

A minimum weight of 2271 pounds has been set for the converged formulas. The increase in weight will accommodate the various KERS systems and engine packages allowed in Hypercar, and the spec system coming to IMSA.

The common practice of have multiple bodywork specifications that suit high-speed/low-drag needs at Daytona and Le Mans has been eliminated as LMDh manufacturers will be granted a single bodywork package to use at every round. Efforts to equalize aerodynamic performance across the various LMDh models will be undertaken by IMSA. And Michelin, which took over the sole supply for IMSA’s WeatherTech Sportscar Championship in 2019, has been nominated to develop and supply its rubber for LMDh.

“We have reached another key milestone with the release of our draft technical regulations for LMDh,” said IMSA CEO Ed Bennett. “There is still more work to be done, but the positive spirit of collaboration between the ACO and IMSA, as well as our four constructors and many interested manufacturers has been fantastic and truly unprecedented. These regulations provide a roadmap for manufacturers and constructors to embark on the design process for new LMDh race cars that will revolutionize the top category of premier sports car racing around the globe.”

“Officially launched in Daytona in January, the ACO-IMSA convergence is now entering an important phase in its implementation,” added ACO president Pierre Fillon. “We are unveiling the basic technical details of this new LMDh category which will allow the same car to race in the FIA ​​World Endurance Championship and the IMSA WeatherTech SportsCar Championship, without any modification necessary to the car. The dream of many manufacturers is finally coming true. Le Mans Daytona h and Le Mans Hypercar will embody the top category of endurance racing. This is a historic and decisive moment for the future of our discipline.”