3D printing technology optimises pistons for the powerful Porsche 911 GT2 RS

Porsche starts testing 3D printed pistons that are 10% lighter.

Automakers are experimenting extensively with 3D printing for all variety of automotive parts from simple interior trim pieces to parts as complex as brake callipers. Porsche is taking the technology a step further by experimenting with 3D printing engine internals.

Mahle, a German parts supplier, and Trumpf, a 3D printer manufacturer, helped Porsche make 3D printed pistons that can survive in a high-performance engine. The company 3D printed a set of six pistons for the 911 GT2 RS with high-purity metal powder using what it calls a laser metal fusion process. Heat generated by laser beams melts the powder surface into a pre-determined shape, so this is far more advanced than your neighbour’s kid’s 3D printer.

Porsche manufactured a set of six 3D printed pistons through a powder-bed fusion technology from Trumpf.

Porsche produced a set of six 3D printed pistons for the 911 GT2 RS

The 911 GT2 RS is equipped with forged pistons as standard, but their potential for use in future high-performance engines is practically exhausted. Improvements have only been possible with changes that could no longer be realised using conventional production methods. In contrast, additive manufacturing makes it possible to implement a so-called bionic design in which material is only used in those locations where forces are transferred. For this topology optimisation, the engineers used a special design method that is matched to the specific conditions of 3D printing. Working with project partners Mahle and Trumpf, it has therefore been possible to reduce the weight of the pistons by 10 per cent and to validate the quality and performance capability of the topological structures with measurement technology from Zeiss.

“We’ve always made sure that we always err on the safe side. Our simulations show that there is a potential weight saving of up to 20 per cent per piston,” says Frank Ickinger, a member of Porsche’s advance drive development department, said in a statement.

Porsche’s 3D Printed Pistons were manufactured in Trumpf TruPrint 3000

The second goal was the integration of an annular cooling duct behind the piston rings. This duct has a special cross-sectional shape and is closed like a tube apart from inlet and outlet openings for oil. Such a structure can be produced only by means of an additive manufacturing process. Thanks to this additional cooling, the temperature of the component has been reduced by more than 20 degrees in the piston ring area, which is subject to extreme thermal loads. The combination of all these measures makes for optimised combustion with higher pressures and temperatures, resulting in greater efficiency.

“Thanks to the new, lighter pistons, we can increase the engine speed, lower the temperature load on the pistons, and optimise combustion. This makes it possible to get up to 30hp more from the 690hp (515kW), twin-turbocharged engine in the 911 GT2 RS while at the same time improving efficiency,” said Ickinger.

The 911 GT2 RS is equipped with forged pistons but as the world moves towards futuristic high-performance engines, the forged pistons cannot deliver the needed performance

The 911 GT2 RS is equipped with forged pistons but as the world moves towards futuristic high-performance engines, the forged pistons cannot deliver the needed performance. One of the goals of this project was to reduce the weight of the pistons and with 3D printing, a topology optimised design can easily be manufactured to reduce material and ultimately the weight of the system.

There’s no word yet on whether 3D printed pistons are as durable as forged pistons. And, similarly, Porsche hasn’t announced whether it plans to put them in a production car, let alone when or how much they will cost.

Porsche did say it has identified other applications for the technology. It introduced 3D printed seat cushions in May 2020, and it offers 3D printed versions of about 20 classic-car parts that are no longer in regular production, such as a clutch release lever that fits the 959.

“This manufacturing technology is also technically and economically interesting for Porsche for special and small series as well as motorsports,” the company said.