Updated: July 8th, 2025.
In a bid to enhance convergence between the Le Mans Hypercar (LMH) and Le Mans Daytona hybrid (LMDh) classes, the FIA, often in collaboration with the ACO and IMSA, has introduced additional lines to the technical regulations of these categories.
Text: Luca W. © Images: FIA, ACO, IMSA, Peugeot, Porsche, Ferrari, BMW ©
However, the distinctions LMH vs LMDh remain unclear to many enthusiasts. This article aims to shed light on these differences, providing essential insights into the technical specifications, participating teams, and other key aspects of these racing categories. Stay tuned for regular updates on this evolving topic.
If you’re more into details, click to jump on a specific topic in the table of contents below.
1. What do LMDh and LMH stand for?
LMDh, or Le Mans Daytona Hybrid, and LMH, which stands for Le Mans Hypercar, are two racing categories set to compete in the Hypercar class of the FIA World Endurance Championship.
2. Will LMDh and LMH race at Le Mans?
While LMH cars are set to race in Le Mans and the FIA World Endurance Championship (WEC) only, the participation of the LMDh category is applicable to both the WEC and the International Motor Sports Association (IMSA) championships. Interestingly, some teams are considering the IMSA championship over the WEC for their LMDh participation.
3. Budget
Both LMH and LMDh categories share several commonalities, with a more in-depth exploration of these aspects to follow in this article.
One key distinction between the two lies in the cost cap. The ACO has emphasized that running two hypercars will incur an 80% reduction in costs compared to LMP1 cars. LMDh emerges as a collaborative response from ACO and IMSA to address cost concerns faced by teams. This move is especially pertinent in the context of challenges posed by the COVID-19 pandemic and the escalating development costs that private teams and even manufacturers find increasingly challenging to bear. In essence, LMDh can be viewed as the evolution of the DPi racing class.
For context, the cost of a LMDh car is capped at €1,000,000 (excluding the Internal Combustion Engine – ICE), while no specific budget limit is articulated for the LMH category. The overarching goal behind introducing these new categories is to establish a Balance of Performance (BoP). This regulatory mechanism ensures that both LMH and LMDh cars can compete on equal footing in the FIA WEC, and notably, LMDh cars have the flexibility to participate in the IMSA Championship.
4. Powertrain
In both LMH and LMDh categories, constructors or teams enjoy the freedom to select the Internal Combustion Engine (ICE) architecture, capacity, and technology.
However, certain power limitations are in place, with the maximum output for the LMDh internal combustion engine capped at 470 kW (630 HP) and for LMH at 500 kW (671 HP). When combined with a hybrid system (67 HP for LMDh and 268 HP for LMH), the total power output should be max. 520 kW (698 HP) for both. With the Balance of Performance (ACO and FIA decision), the power output can be raised or reduced.
Tired to convert power units? Try out our live unit converter!
In the LMH class, Peugeot is using a 2.6-litre, turbocharged V6 engine, while Toyota opts for a a 3.5-litre V6 twin-turbo engine, delivering 671 hp to the rear wheels.
LMH internal combustion engine is complemented by a 272 hp motor generator unit (electric). It’s crucial to note the necessity for electronic management of power delivery to align with the specified combined power output of 671 hp. An interesting distinction lies in the hybrid system capabilities, where the LMH hybrid system can distribute power to both front and/or rear wheels, while the LMDh hybrid system is exclusive to the rear wheels.
Compared to the LMP1 class, there should be a 30% power drop.
However, an exception comes with the 2025 newcomer, the Aston Martin Valkyrie AMR-LMH. Unlike its competitors, this car is powered by a naturally aspirated 6.5L V12 engine developed by Cosworth. It does not incorporate hybrid technology and relies entirely on combustion, sending power exclusively to the rear wheels. It is the only Hypercar using 2-wheel drive technology.
5. Weight
In a bid for clarity, the FIA has stipulated that cars in both categories should weigh 1,030 kg. For those who like to delve into the numbers, this represents a 15-20% increase in weight when compared to LMP1 cars.
6. Le Mans Hypercar and LMDh platform
In a move tailored to manufacturer preferences, the LMH platform is a prototype that stems from an existing road-legal hypercar or supercar, or vice versa. Article 19.1 of the LMH regulations specifies the requirement to produce 20 road-legal cars for entry into the Hypercar category. As an illustration, Toyota intended to market their LMH prototype, although these plans were eventually shelved due to incidents.
On the other hand, the LMDh platform (chassis) is intended to be a shared framework for many teams, exclusively provided by manufacturers such as Dallara, Oreca, Multimatic, or Ligier.
Notably, Porsche has teamed up with Multimatic, and Cadillac with Dallara to craft their platforms.
The spine of the car (complete but without bodywork, engine, hybrid) is identical to future LMP2 cars, with commonalities in wheelbase (3,150 mm), and adherence to regulations in width and length (2,000 mm and 5,100 mm, respectively).
7. Aerodynamics
Aerodynamics in both LMDh and Hypercar categories are subject to regulation, such as the downforce/drag ratio capped at 4:1. Despite these regulations, competitors have the freedom to use identified bodywork that aligns with their brand identity. The regulations aim to evoke the aesthetics of the ’90s, fostering distinctive, identifiable, and conventional car designs, although this isn’t entirely realized as of 2023.
An illustration of this is evident in the Toyota GR010 (Toyota’s Hypercar), where the body design clearly echoes the aesthetics of previous LMP1 prototypes.
Peugeot adopted a distinctive approach to aerodynamics with its 9×8 Hypercar. A notable feature is the absence of a rear wing. Regulations currently permit only one adjustable aerodynamic element, leading Peugeot to explore alternative solutions through simulations. However, the 2023 season revealed that Peugeot’s strategy lead to struggle, prompting plans for the introduction of a rear wing for the 2024 season.
8. Hybrid system
In the LMDh category, the hybrid system is shared among competitors, capable of regenerating up to 200 kW and delivering 50 kW to the rear axle. Bosch is responsible for motor development, while Williams Engineering manages power and energy storage, and X-trac handles gearing. However, this hybrid system is restricted for use at speeds above 120 kph.
Conversely, the LMH category provides flexibility in hybrid system architecture. While not mandatory, it typically mirrors the road legal sports car and can deliver up to 200 kW to one end, allowing LMH cars to be either 4-wheel drive or exclusively rear-wheel drive. Teams have the autonomy to develop the gearbox, potentially offering a performance advantage. Nevertheless, the LMH hybrid system cannot be utilized under a given speed, set by the Balance of Performance.
The speed threshold to trigger 4-wheel drive can be modified with the Balance of Performance, like weight, and maximum power output.
9. When will the category start?
The Le Mans Hypercar series commenced in the 2021 season, with the anticipated entry of some LMDh cars scheduled for 2023. Notably, BMW, Lamborghini, and Alpine joined the competition, making their presence felt at the 24 Hours of Le Mans in 2024.
10. Le Mans Hypercar and LMDh entries
Here is a small table that recaps all entries in each category:
| LMH | LMDh |
| Toyota | Porsche with Team Penske and Proton Competition (customers) |
| Ferrari with AF Corse AF Corse customer | Acura (IMSA) |
| Peugeot | Cadillac JOTA in 2025 (customer) |
| Aston Martin (2025) | BMW Motorsport with WRT |
| Ford (2027) | Alpine |
| McLaren (2027) | Genesis/Hyundai (2026) |
| Bugatti (rumour) | Phoenix Racing (rumour) |
| Alfa Romeo (rumour) | |
Both categories will have a unique tire supplier (Michelin).
11. The FIA technical regulations issue
If you are curious enough to go deep into the detailed technical rules, feel free to download the updated LMH FIA issue of October 2023 and the updated LMDh FIA/IMSA issue of April 2025.
12. Are LMH and LMDh faster than LMP1 cars?
No, they are slower. In the 2023 24 Hours of Le Mans Hyperpole (last step of qualifying): the fastest LMH car lapped in 3:22.982: 7.715 seconds slower than the 2020 LMP1 cars in qualifying. Almost a second faster than 2021 LMH cars.
This performance difference is primarily attributed to the fixed weight (1,030 kg) and power output (671 hp) regulations. For instance, the Toyota GR010 (LMH) is 152 kg (17%) heavier and has 32% less power than the 2019 Toyota TS050 Hybrid (LMP1), resulting in a lower power-to-weight ratio and slower lap times.
Despite these factors, detailed data analysis reveals that the performance gap is less pronounced, amounting to just under 2 seconds on a shorter track, such as the 6 Hours of Spa Race.
The chart below illustrates the lap time comparison between the categories at the 2023 24 Hours of Le Mans race:
13. In a nutshell
What do these new regulations bring to the table? Well, a lot, actually.
Firstly, we are witnessing a golden era as both categories showcase remarkable parity in terms of performance. Secondly, as of now, a dozen manufacturers have already embraced the program, and judging by the enthusiastic response from constructors, more are likely to join in the future.
Moreover, this initiative significantly curtails costs, enabling smaller teams to enter the fray and compete on equal footing with larger counterparts.
Lastly, the concept of a showcase has never rung truer, as certain road technologies seamlessly integrate into the cars and vice versa.
