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BMW Confirms Engine Layout for LMDh Car

BMW M Motorsport boss details DTM-derived engine choice, dyno testing for LMDh car…

Image: BMW M Motorsport

The head of BMW M Motorsport has confirmed that the company’s LMDh car will be powered by a turbocharged version of its 4-liter, V8 engine previously used in DTM.

BMW revealed the first details and footage of its LMDh powerplant during a recent episode of its Mbedded in-house documentary series, including the use of an old DTM unit as the base.

Andreas Roos has since confirmed the 4-liter V8 engine configuration, which will be attached to the LMDh formula’s common electric motor used by all manufacturers.

“It’s based on the former DTM engine, the eight-cylinder,” he told Sportscar365.

“From the regulations, and how it is with the power curve, we did some investigation on what could be the best engine.

“The investigation showed that we can base it on the V8 from the DTM and have it turbocharged. This is the best compromise for an engine like this.”

BMW M Motorsport looked at other available engine types, including the turbocharged 2-liter straight four-cylinder used in its Class One DTM cars between 2019 and 2020, but found the eight-cylinder P66 model to be the most suitable option for LMDh.

This is despite the turbocharged P48 turbo DTM engine producing an output that sits closer to the 670 hp maximum for LMDh, compared with the chosen P66 base.

“There are several engines: we have engines from the M8 [GTE], the latest four-cylinder engine from the DTM and the V8 from the DTM,” Roos said.

“An investigation was done, with the pros and cons of what could be the best engine and how you can do it.

“You have to change quite a few things on the engine because it is [being] turbocharged.

“The DTM engine was developed in 2012, some time ago, so there are some things that we are changing and doing. The first runs were done with the base engine, and now there are some updates in.

“It’s looking good, and I think it’s a good way to fulfill the regulations in terms of the power curve.”

Engine dyno testing has been carried out in phases. BMW first ran the base V8 on its own, then made some tweaks to create an ‘interim’ engine that was used to confirm the configuration’s viability for the required LMDh performance windows.

This was followed by endurance running to verify the engine’s reliability over several hours of usage.

The engine needs to generate significantly more power than it did in the DTM when it made around 500 hp.

Roos confirmed that the complete integrated BMW M LMDh powertrain comprising the engine, gearbox and electric motor has been tested on a dyno rig.

This appears to indicate that the company’s first sports prototype since the 1999 24 Hours of Le Mans-winning V12 LMR is not far from undergoing its first shakedown.

Team RLL is set to campaign two BMW M LMDh cars as a factory team in the GTP class of next year’s IMSA WeatherTech SportsCar Championship.

“We have started to do endurance runs on the dyno,” Roos explained.

“You have to investigate if your engine is capable and reliable before running the car.

“We have done a lot of development work already on the dyno, with the complete drivetrain. And then we go into the car.

“When you do endurance testing, you have to do the complete system. Then we will see how it fits into the complete car.”

Roos anticipates that the first rollout of the BMW M LMDh will take place with the full hybrid system installed. Porsche, which is so far the only LMDh manufacturer to have done any track testing, gradually introduced the common electric motor in stages.

“We want to do it like this,” Roos said. “Our time schedule is quite tight, so there is no time to run an interim version.

“This is why we put a lot of effort into the development on the dyno so that we can be as well-prepared as possible when we start in the race car.

“The engine is one important piece of the whole thing. You need every screw and bolt on the car, but the drivetrain system is an important topic. Everything has to fit together.”

Daniel Lloyd is a UK-based reporter for Sportscar365, covering the FIA World Endurance Championship, Fanatec GT World Challenge Europe powered by AWS and the IMSA WeatherTech SportsCar Championship, among other series.

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