Le Mans Hypercars: Top speed, rules & how they differ from LMP1

The Le Mans Hypercars that have arrived in the World Endurance Championship in 2021 are very different to their LMP1 predecessors - in concept, look, cost and speed.

LMH and the LMDh sister formula, which will become part of the WEC in 2023, are a brave attempt to reset the agenda in international sportscar racing. On the evidence of who has already said they are going to join the party over the next two years — Ferrari, Peugeot, Porsche, Audi and more — a glorious new era beckons.

The concept

The LMH rules, which were two or more years in the making, are arguably less prescriptive than any other set of rules in motorsport history. They don't so much as lay down what a manufacturer can and can't do as in LMP1 and just about every other category of racing; rather they set out the outcome of the design process.

There are performance windows, which include maximum downforce and minimum drag figures, into which each car must fit. Engine power — and the way it is delivered to the track — is strictly controlled.

The figures laid down by the rules are relatively modest in an effort to lower the bar and level the playing field. LMH is also a non-development formula. Once the car is homologated, its specification is fixed for a full five years. So-called development tokens are allowed over that time-span: manufacturers may apply to the FIA's Endurance Committee to make changes for either performance or reliability reasons to sub-systems of the car.

Glickenhaus opted to miss first WEC round of 2021 before locking the car into five-year homologation

Photo by: Marc Fleury

Reduction in cost...

A drastic decrease in the the cost of entry was the starting point for the rule-making process that led to LMH in the wake of the withdrawal of first Audi and then Porsche from LMP1. The class as conceived to allow for budgets that are just a fraction of those in LMP1.

Annual budgets approaching €200 million were talked about for the LMP1 rocket ships raced in the WEC by Toyota, Audi and Porsche between 2012 and last season, whereas the target for LMH was €30 million. It is impossible, of course, to know how much people were or are spending, but there's no doubt that seven-figure budgets are a thing of the past.

...And a reduction in speed

This can be said with complete certainty. Making the cars slower was one of the keys to making them cheaper. The reduction was based on an average race lap time around the 8.47-mile Circuit de la Sarthe at Le Mans of 3m30s. Compare that to the 3m20s average for the winning Toyota TS050 Hybrid in 2018.

But expect the cars to be going a little bit quicker come the qualifying sessions on Wednesday and Thursday of Le Mans week.

High costs prompted Audi and Porsche to quit LMP1, with both subsequently moving to Formula E

Photo by: Audi Sport

A new look

The new freedoms in the aerodynamic rules and the relatively modest targets allow manufacturers to give their machinery a road-car look. Toyota has developed its new GR010 Hybrid LMH in parallel with a forthcoming super-sportscar for the road, a car that was shown in concept from as the GR Super Sport as long ago as January 2018.

Peugeot, whose 9X8 will arrive in the WEC some time next season, has chosen to imbue its LMH with styling cues from its model range.

The rules also allow a manufacturer to come with road-based machine. Aston Martin was planning this route with the Valkyrie super-sportscar conceived by Red Bull Racing designer Adrian Newey. The project was subsequently axed and it remains unclear if anyone will come at LMH from this direction.

Heavier cars...

The weight for an LMH car yo-yoed up and down from when the broad tenets of the rules were laid out at Le Mans in 2018. It went as high as 1100kg before settling at 1030kg for two-wheel-drive cars and 1040kg for four-wheel drive.

The final downward shift reflected the convergence with the LMP2-based LMDh rules that come on stream in 2023. The higher weight in comparison to LMP1, which had a 878kg base minimum for hybrid machinery, reflects the drive to reduce costs.

...And bigger cars

An LMH car is bigger than a LMP1 in every dimension. The rules allow an LMH to be 250mm longer, 25mm wider and 100mm higher than an LMP1 to help the designers incorporate styling ideas. The increase in height also reflects new cockpit safety standards that define a more upright seating position. The overhangs, front and rear, are also longer.

Hypercars are much bulkier than their LMP1 predecessors

Photo by: Marc Fleury

Engine power

An LMP1 Hybrid had the potential to push out approaching 1000bhp — about half and half from its internal combustion engine and its motor-generator units. Power from the hybrid system was subsequently capped at just over 400bhp (300kW). Total power in LMH has been reduced to just under 700bhp, or 520kW as it is written in the rules. The power output was, like minimum weight, a moving target as the LMH rules evolved.

Maximum power from the single hybrid system is now set at 200kW (4268bhp), which means a higher output from the conventional engine. That explains why Toyota now runs a 3.5-litre twin-turbo V6 rather than a 2.4 litre.

The hybrid punch is no longer the overtaking tool that it was in LMP1. A power curve is laid down for each car — and enforced with torque meters in each driveshaft — that incorporates both element of the drivetrain for hybrids. Push to pass is a thing of the past.

Hybrid power cannot be deployed when the cars are travelling at under 120km/h, a move designed to remove any advantage of four-wheel-drive in slower-speed corners. The deployment minimum is set at 150km/h in wet conditions, categorised by when a car not running on slick tyres.

Hybrid system is no longer the push-to-pass tool it used to be in LMP1 era

Photo by: Motorsport Images

Less tech

The LMP1 rules allowed for two energy-retrieval systems. Toyota, for example, went for front and rear-axle kinetic systems, while Porsche harvested energy from the exhaust gases as well as the front wheels.

The new rules allow for only a single kinetic system on the front axle. It was mandatory in the original LMH regs published in December 2018, but this requirement disappeared as the rules changed over time in an effort to open up the category to more participants. US manufacturer Glickenhaus has taken the non-hybrid route for its Pipo-engine 007 LMH.

Linking the front and rear suspension with what is termed a FRIC system in Formula 1 is banned. Toyota employed something along these lines on its TS050 Hybrid LMP1. Brake by wire is currently banned, but will be allowed for non-hybrids in the future.

Wheels and tyres

The LMH rules allow for two ways to skin a cat. The cars can run with 14in wide tyres front and rear or 13.5in fronts and 15in rears. Toyota has gone the first route, Glickenhaus the second. The idea is that the wider rears will compensate for the advantage in terms of tyre wear of running a front-wheel-drive car.

Glickenhaus runs two different dimensions of wheels, as permitted by the rules

Photo by: Rainier Ehrhardt

Aerodynamics

Part of the drive to limit costs is a ban on multiple aerodynamic configurations. Manufacturers used to turn up to Le Mans with aerodynamics conceived specifically for the unique demands of the Circuit de la Sarthe. Just one aerodynamic configuration is allowed under the LMH rules: it is homologated in the Sauber Group windtunnel in Switzerland and the body surfaces scanned to aid the enforcement of this rule.

A single adjustable device is permitted: Toyota has chosen the rear wing, while Glickenhaus has only told us that it has opted for an element in the front aero package.

In other ways, however, the regulations are much more open than in the days of LMP1. An example of this is the rear diffuser: the rules are now free, whereas for LMP1 Hybrids they ran to more than 200 words and stipulated a maximum tunnel height of 150mm. There is also no requirement for a section of flat floor, save for the mandatory skid plank.

This explains how Peugeot has been able to do away with a conventional rear wing on the 9X8. Freer regulations have allowed its designers to generate the required level of downforce from the under surfaces of the car.

The Peugeot 9x8 that will enter the WEC next year has been designed without a rear wing

Photo by: Francesco Corghi

The dorsal fin

The Toyota and the Glickenhaus both have dorsal fins like LMP1 cars, but the strict dimensions laid down in the old rules from 2011 have disappeared. Now figures on lateral stability are laid down in the rules. Peugeot's show car has a much smaller fin, while the strakes on the rear wing of the Glickenhaus are also linked to this regulation.

The Balance of Peformance

The idea that the performance of all cars was introduced into the rule book in 2019. It was condition of Aston Martin's proposed entry into the category with a car that would have been a non-hybrid. A BoP table is published ahead of each race, laying down the torque curve, amount of energy per stint and minimum weight of each car.

Alpine has entered a grandfathered LMP1 car in the Hypercar class, and receives a less-favourable BoP as a result

Photo by: Marc Fleury