The world of endurance racing is in the midst of its revolution and the 2020 vintage brought not only the infamous Coronavirus pandemic, but also the excellent news of the convergence of regulations between the major championships.
In fact, the agreement reached between IMSA and Automobile Club de l’Ouest / FIA to have in both their leading series – namely IMSA SportsCar Championship and FIA World Endurance Championship – the new generation prototypes competing together, after years in which Daytona Prototype International (DPi) and Le Mans Prototype 1 (LMP1) had been protagonists in their respective championships, but never against each other.
The two Federations and organizations have found an agreement and from 2023 the brand new Le Mans Hypercar (LMH) and Le Mans Daytona Hybrid (LMDh) will be able to be on the same grid and in battle; but how do these two types of prototype work specifically? Let’s try to shed some light on a historical moment in which a tide of Manufacturers is embracing one or the other machine.
Pierre Fillon, ACO President, Jim France, IMSA Chairman, Gérard Neveu, AD FIA WEC, John Doonan, IMSA President, and Ed Bennett, AD IMSA CEO
Photo by: Michael L. Levitt / Motorsport Images
LE MANS HYPERCAR
The Hypercars officially debuted in the 2021 season of the FIA World Endurance Championship and at the 24h of Le Mans thanks to the Toyota and Glickenhaus brands. They were joined by Alpine, which had a derogation for 2021-2022 in the use of the old Oreca LMP1 (once from Rebellion) called A480.
The LMH Class replaces the LMP1 in the world top endurance series and in the French Classic which takes place on the Circuit de la Sarthe, and gives manufacturers greater freedom of action between design and construction of their vehicles.
A lot of work has been done since 2018, the year in which the first proposals from the manufacturers were made to the FIA and ACO, even if not all of them later joined (first of all Aston Martin slipped away with his Valkyrie never deployed). Among the various discussions – also to avoid reaching the unsustainable expenses that the LMP1 had reached – a regulation was drafted approved by the FIA World Council a couple of years ago.
# 8 Toyota Gazoo Racing Toyota GR010 – Hybrid by Sebastien Buemi, Brendon Hartley, Ryo Hirakawa
Photo by: Paolo Belletti
Each brand can homologate a car that has at least 20 units of a reference road model; when the process is completed, the racing car is ‘frozen’ for 5 years, with the only use of 5 tokens (called ‘tokens’) to make changes, especially if it is about solving performance issues, while if they concern the reliability of the operations are obviously to be agreed with the FIA and ACO.
The engine, with a minimum weight of 165kg, can have any displacement, it must be petrol and can be combined with an electric unit making the whole hybrid, but without ever exceeding 500kW (about 680CV) of maximum power.
The gearbox also has a minimum weight of 75kg with the mandatory use of aluminum or magnesium parts, the suspensions are instead simplified with a mandatory double arm design and prohibition of aids such as active and so-called systems ‘mass damper’.
# 708 Glickenhaus Racing Glickenhaus 007 LMH by Olivier Pla, Romain Dumas, Pipo Derani
Photo by: JEP / Motorsport Images
The hybrid comes into action on traction when fitted with slick tires from 120km / h upwards – but with changes that can be made according to the Balance of Performance regulation – and can also be used individually in the pit lane, but without never go beyond the continuous 200kW.
And the BoP is applied by the FIA to balance the performance of the various competing models, acting not only on the power levels and on the maximum energy to be exploited in the various driving shifts (calculated in MJ), but also on increases and decreases in weight (1030kg minimum) from race to race.
As for the other maximum measurements, an LMH must be 5m long, 2m wide and with a pitch of 3.15m, while the rest of the design is quite free and at the discretion of the brand, obviously remaining within the parameters imposed by the technical regulations.
LE MANS HYPERCAR TECHNICAL REGULATION
Ferrari LMH
Photo by: Davide Cavazza
LE MANS DAYTONA HYBRID
The LMDhs are the other type of new generation prototype, mainly designed to take the place of the DPi in the IMSA SportsCar Championship from 2023, where we will have a new dedicated class called GTP.
Compared to the Hypercar ‘cousins’, this regulation is a bit more restrictive and limiting for the manufacturers who embrace it, but with the advantage of lower overheads (ceiling of € 1 million excluding the internal combustion engine) for the construction and also the ability to sell their products to customer teams.
To begin with, the cars will have to be hybrid (as defined by the ‘h’ in the name), designed and built on the basis of a common chassis that four selected suppliers will give to the brands, namely Ligier, Multimatic, Oreca and Dallara, without having to refer to road or series production models.
Porsche 963 LMDh
Photo by: Morgese / Gandolfi
The frame is not the only thing imposed by the regulation, which also provides other equal parts for everyone. The batteries come from Williams Advanced Engineering, Bosch will provide the software for power management between hybrid and thermal engine, inverter and regenerative brake-by-wire braking system, while Xtrac will take care of the gearbox. The hybrid system of the LMDh must be mounted at the rear and can be of 200kW, discharging it on the 50 axis.
For the rest, the manufacturers can proceed to design a body that identifies them stylistically, with a ratio of 4: 1 in aerodynamic load / drag, taking into account that – as for the Hypercars – the maximum power allowed is 500kW ( 680CV) and the minimum weight of 1030kg (180kg for the engine), with a length of 5.1m, width of 2m and wheelbase of 3.15m.
Again, the homologation is valid for 5 years and a Balance of Performance will be applied to level performance, especially when the LMDhs come face to face with the Hypercars in races such as Daytona and Le Mans.
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