On Monday, BMW became the first automaker to unveil its new hybrid racing prototype built under the new LMDh rule set. It’s called the BMW M Hybrid V8 and will make its debut at the Rolex 24 at Daytona next January.
Sports car racing is in the midst of a transition as race organizers in the US and Europe enact new rules for prototype race cars. Since it’s a sports car race and there are two groups of organizers, it’s all a bit complicated.
The 24 Hours of Le Mans is organized by the French Automobile Club de l’Ouest (ACO). Many of the cars that compete in this race also compete in the World Endurance Championship organized by the Federation Internationale de L’Automobile (or FIA). In the US there is the International Motor Sports Association (IMSA) which hosts the WeatherTech Championship.
Everyone agreed it was time for a new set of rules for prototypes, but the ACO was going in one direction and the IMSA in another. The ACO has developed a class, originally called Hypercar and now called Le Mans Hypercar (LMH), for purpose-built endurance racing cars. These can be hybrid or powered by an internal combustion engine, and they may or may not be derived from a road car – it’s up to the manufacturer.
LMH started in 2021 and this year’s 24 Hours of Le Mans, which takes place next weekend, has entries from Toyota, Glickenhaus and Alpine. In the next few years we should see cars from Peugeot and Ferrari, among others.
The IMSA concept is called LMDh, for Le Mans Daytona Hybrid. It is an evolution of IMSA’s successful DPi category, which in turn was derived from the ACO’s highly successful LMP2 category. Companies don’t have to design an entire race car from scratch; Instead, every LMDh car starts with a chassis (or backbone) from one of four approved manufacturers – Dallara, Ligier, Multimatic and Oreca.
The OEM supplies the motor, electronics and styling. However, many components are specified and common to all competitors to keep costs down. These include the hybrid system, which combines a Bosch electric motor-generator unit, a Williams Advanced Engineering lithium-ion battery and an Xtrac transmission.
This is where it gets a bit complicated: Despite the two different rule sets, both IMSA and ACO want teams from the other series to play in their sandboxes, so there is an equivalence process to match the performance of LMDh and LMH. (I’ve written in more detail about how this has worked in the past.)
In the case of BMW, it works with Dallara, which has had a lot of success with Cadillac in DPi in recent years. BMW didn’t give any details about the M Hybrid V8 other than to say that the BMW engine behind the cockpit is a V8 (but you probably worked that out from the name).
We can see how the OEM used LMDh’s design freedom to connect the prototype to its road cars, particularly the large front grille. The LMDh rule set calls for a low downforce to drag ratio of 4:1, so there isn’t really an aerodynamic penalty for using street car styling elements.
BMW’s M Hybrid V8 may be the first LMDh car to officially break cover, but it’s not the first to start testing. Working with Multimatic, Porsche had a head start on all of its LMDh competitors and began testing its unnamed race car in January. And in the past few days, both Acura and Cadillac have been teasing their own LMDh cars; They were scheduled to compete in Daytona next January.
BMW initially planned to use the M Hybrid V8 only in North America as it is the brand’s largest market. But now it’s believed that a start at Le Mans in 2024 could be a possibility.
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