BMW LMDh prototype engine based on old DTM V8 unit

The German manufacturer has confirmed the open secret that it has chosen to base the engine for the BMW M Hybrid V8 on the powerplant used in the M4 DTM for two seasons before a change of regulations for 2019.

The latest announcement on the LMDh programme from BMW reveals that LMDh engine known as the P66/3 retains the four-litre capacity of the normally-aspirated DTM unit and that it now runs direct injection.

It follows the naming of the car as the M Hybrid V8 in June without confirmation of any technical details, which accompanied the release of the first photographs of the car that will be raced by the Rahal Letterman Lanigan Racing team in IMSA next season.

BMW also evaluated the in-line four-cylinder turbo engine used in the DTM after a change in rules for 2019 and the road-based V8 turbocharged engine from the M8 GTE, which raced in both IMSA and the FIA World Endurance Championship.

Ulrich Schulz, head of drivetrain design at BMW M Motorsport, said: “During the evaluation phase, we also took a look at the P48 four-cylinder turbo engine from the [2019-spec] BMW M4 DTM and the P63 eight-cylinder turbo engine from the BMW M8 GTE.

“But potential problems with the durability of the P48 and the heavy weight of the P63 were negative considerations.”

BMW M Hybrid V8, P66/3 engine

Photo by: BMW

Schulz explained the BMW was able to use experience from its Formula 1 participation in 2000-09 in the development of the internal combustion component of the LMDh’s powertrain, which is mated to a one-make hybrid system developed by Williams Advanced Engineering, Bosch and Xtrac.

“That saved us time and a lot of money and was therefore efficient and sustainable,” he said.

“Efficiency is a critical factor for this project, as we have a very short period of time available between getting started and the first racing appearance at the Rolex 24 at Daytona in January 2023.

“Converting the normally-aspirated P66/1 engine into a bi-turbo and then working with the electric drivetrain colleagues to turn it into a hybrid drive system was very complex.”

The new engine has already been fired up in the M Hybrid V8 developed in conjunction with Dallara in Italy.

The car will begin testing at the Varano circuit close to Dallara’s headquarters in July.

The initial phase of the test programme for the M Hybrid V8 is understood to be scheduled entirely for Europe.

The focus of the BMW LMDh programme will initially be on the IMSA series with two factory cars from Rahal Letterman Lanigan Racing, but the German marque has already opened the door on a potential WEC programme in 2024.