Le Mans 2021: How new hypercar rules are shaking up the grid

But while every LMH and LMDh car will theoretically be capable of the same pace and performance, the various rules still allow for vast differences and, vitally, creativity.

Le Mans hypercar

The LMP1 prototype regulations date back to 1992. At their core, they offered manufacturers powertrain and technology freedom that was absent from other top-level racing. As a result, manufacturers used LMP1 to showcase new technology, and in its final decade the focus shifted to highly sophisticated hybrid powertrains. It therefore became hugely expensive, leaving privateers unable to compete and prompting an exodus of road-car makers until, from 2018, only Toyota remained.

The aim of the hypercar rules is to cut costs while still allowing manufacturers to use advanced, road-relevant technology.

“There has been not only a regulation change but a regulation principal change,” says Toyota technical chief Pascal Vasselon. “In LMP1, the regulations were prescriptive, so we were told ‘don’t do this, don’t do that’. In LMH, we have a performance target: we can do what we want, but you have to fit into a very precise performance window.”

The rules actually allow for two basic types of hypercar. The first are bespoke racing prototypes, including 2021 machines from Toyota and US low-volume specialist Scuderia Cameron Glickenhaus, plus future cars from Peugeot and Ferrari. Cars based on road-going hypercars are also allowed – although after Aston Martin canned its plan to race the Valkyrie in favour of a Formula 1 entry, none of these are in the works.

The dimensions of the hypercars are set and there are controls on key bodywork areas, with development not allowed. Cars must send the power from their combustion engine to their rear wheels, but they can fit an electric motor of up to 268bhp for driving the front axle to enable four-wheel drive. Entries based on road-legal hypercars must retain the hybrid layout of the original.

To level performance with the rear-driven LMDh cars, LMH cars will be unable to deploy hybrid power below 75mph in the dry (a wet-weather speed has yet to be finalised).

Otherwise, the powertrain rules are open, giving manufacturers the freedom to develop the ICE and hybrid units with whatever technology they wish, resulting in some variety. For instance, Toyota’s GR010 Hybrid uses a 670bhp twin-turbocharged 3.6-litre V6, while Peugeot’s car will use a 670bhp twin-turbocharged 2.6-litre V6. Both feature a 268bhp electric motor – and, yes, that means their total output exceeds the 670bhp limit: the drivetrains will automatically balance output from the two sources to maximise efficiency. In contrast, Glickenhaus’s 007 will use a non-hybridised twin-turbo 3.5-litre V8.

Despite the demise of the LMP1 class being largely a result of rising budgets, the LMH rules don’t include any form of cost controls. The need to be within a performance window and the use of BoP should make that unnecessary by ensuring that an advantage can’t be bought.

Le Mans Daytona hybrid

When they first appear in 2022, the LMDh cars should look and perform close to LMH machines – but their underpinnings are based on fundamental philosophical differences. Those are rooted in the American IMSA Sportscar Championship, which has long favoured rules that control costs and keep the competition close.

LMDh cars will replace the current Daytona Prototype International (DPi) cars – bespoke racing machines built around modified LMP2 chassis that teams must purchase from an approved constructor.

That rule continues with LMDh: all entrants must buy a chassis from Dallara, Ligier, Multimatic or Oreca. As with LMH, aerodynamics will be largely set, with teams given styling freedom in certain non-performance areas. As with LMH, teams can develop their own combustion engines – although for LMDh cars, the output of these is fixed to 630bhp. All cars then feature a spec hybrid element comprising a motor and battery that produces 67bhp. All of the power is sent to the rear wheels.

The mandatory use of a spec chassis and hybrid system makes LMDh cars hugely cost-effective: a car minus its engine should cost around $1.1 million (£860,000). That relatively low price for the ability to race in IMSA’s marquee Daytona 24 Hours and Sebring 12 Hours races, as well as the Le Mans 24 Hours, was the appeal for Porsche, which has chosen LMDh as the route for its return to Le Mans in 2023.