How Porsche intends to work around LMDh reliability issues

For all four manufacturers in the IMSA GTP class, just starting at the 2023 24 Hours of Daytona is a small victory. In many cases, the LMDh cars have only been rolling for half a year. The Porsche 963 has a lead of another six months. Nevertheless, neither Porsche nor the competition see an advantage. So how can reliability problems be avoided if possible?

Jonathan “JD” Diuguid, Head of Porsche Penske Motorsport, explains that they are prepared for problems: “The mechanical reliability of the car is already very good and of course we have experienced people if we do have to change a body part or a gearbox. We have plans for every eventuality, both in terms of software and mechanical components.”

However, the latter are no longer the big problem in modern vehicle construction. The engine, drive train and brakes are very stable thanks to decades of development. The races of the Endurance World Championship (WEC) in recent years have shown that it is often software problems that paralyze the cars. So-called “power cycles”, i.e. vehicle resets, have become a familiar sight.

Redundancy the best weapon against software problems

And this is exactly where Porsche wants to trick fate and uses strategies from aircraft construction. The magic word is redundancy, explains Diuguid: “There are hundreds of sensors on these vehicles to ensure that things run optimally. However, this can also run suboptimally if only half of them are working.”

“It’s mainly about understanding the interdependencies between the sensors and how they work. And how to develop software control strategies so that they work without this information.”

An example of how a single sensor can cost an entire race was Audi Team Land at the ADAC GT Masters in Zandvoort 2022. A sensor in the gearbox prevented Jusuf Owega and Ricardo Feller from even starting. Such problems can be circumvented by redundancy – for example, by using three sensors and being able to cope with the loss of one.

“You think of every conceivable scenario and build software redundancy there,” the Penske man continues. “These cars are extremely complex from a software perspective, but that’s exactly what allows us to address issues with software fixes.”

And this is exactly where Porsche could still have an advantage: Although a lot of pioneering work had to be done, it also had more time to solve unexpected problems with software redundancy.

Another example is the battery, a unitary component from Williams Advanced Engineering. This is intended for a specific temperature window: “We have to change it every time [wie einen Verbrennungsmotor] bring it up to temperature before we get started. There are thermostats and controls all over the car in case we need them.”

Williams has also already taken precautions to keep performance losses within limits if it gets as cold in Daytona as it will in 2022: The battery has 130 percent of the power it actually needs to generate the necessary power even under suboptimal conditions.

Hardly possible to compare to the 919 Hybrid

How was the development work with the 963 compared to the LMP1 bolide 919 Hybrid? For Urs Kuratle, Head of Factory Motorsport LMDh at Porsche, the most recent project was even more difficult, although the complexity of the LMP1 cars of the 2010s is not likely to be reached again any time soon.

“With the 919, everything was an in-house project, which clearly made life easier for us. Now we had problems that were out of our hands. The 919 had significantly more hybrid power and was more complex. Ultimately, you can say that , that the effort was quite comparable for both. Only the difficulties lay in a different area.”

The manpower of the projects, on the other hand, is less comparable. 250 people were involved in the 919 Hybrid. It was easy to count because they were Porsche employees. In the case of the LMDh project, this is no longer so easy to determine.

“It’s difficult to say because only Porsche Penske Motorsport has bases in Mooresville and Mannheim. Then we have our people in Weissach in the development department and the people at Bosch, Williams and Xtrac for the LMDh standard components.”

“So there could be more people overall than in our LMP1 project. But then they don’t just take care of one team, but also other teams and manufacturers. Once these standard components work as they should, then the number of employees in this area will be reduced.”