The Carrera S’s 3.8-liter DI flat-six was named Best New Engine – but for Porsche it’s one of the family
Author: Graham Heeps
Porsche was delighted to add an International Engine of the Year Award to its trophy cabinet for the second straight year. Having made the short trip from Weissach to the Stuttgart Messe to collect the Award on behalf of his talented team of engineers, Thomas Wasserbäch, general manager base engine development department flat-six told ETi: “We’re very proud to get this Award, because the new engine was a lot of work for everybody! We also installed a completely new assembly line at Zuffenhausen, so it wasn’t just a big project in research and development, but also in production, in marketing and elsewhere. It shows us we’re on the right track in optimizing what is really the heart of Porsche – the flat-six.”
It was the 3.8-liter direct-injection ‘boxer’ from the Carrera S that took the prize for Best New Engine, but as Wasserbäch explains, that particular motor is but one of an entirely new family of sixes. “The flat-six engine is a concept that is 45 years old and it’s not often today that you find concepts with such a long evolution,” he notes. “This new family shares parts not only across the rear-mounted Carrera engines, but also the mid-mounted Boxster and Cayman units.”
In developing the new range of sixes, Porsche targeted more power and better response, along with enhanced fuel consumption and emissions, and a lower engine weight and height (the target was a 30mm reduction). “The result is that we now have engines that have 8-10% better performance, with 15% lower CO2 emissions,” says Wasserbäch proudly.
To help provide the power and response drivers expect from a Porsche engine, the rev limits were raised to around 7,500rpm. Friction reductions in the engine helped make that possible, and also benefited fuel economy. “To help reduce friction we’re using DLC coatings on the piston rings and in the valvetrain,” explains Wasserbäch, who joined Porsche from Audi some 10 years ago. “Elsewhere we’re using an electronically controlled (but chain-driven) oil pump; it’s regulated by volume and pressure, so we only have as much oil in circulation as we really need. That in itself brings a 2% improvement in fuel consumption.” He adds that the oil demands of high-performance circuit driving – up to 60 liters of oil per minute at high engine speeds – ruled out a fully electric pump as too large and power-intensive.
The Carrera S’s direct-injection system is supplied by Continental and the injection pressure in the magnetically controlled system is up to 120bar. Wasserbäch says a three-piston pump is used, while the entire system is made from iron to make it suitable for use in markets worldwide.
He’s proud of the solutions for both the oil pump and the injection system, but adds that the little things were just as important to the project’s success as the bigger technology pieces: “There were many small steps to reduce friction and weight, for example our crankcase weighs 10kg than in the previous engine,” he says. “Together, these made up the big step that was this completely new family of engines.”
As for the future, expect more of the same from the Stuttgart sports car maker. “Our focus is to build on the advantages of the flat-six and further increase its sporting characteristics, with higher engine speeds, higher specific power, lower fuel consumption and lower friction,” he promises. “We’re always working to make it better.”