So it turns out the 'unnamed Italian supplier' for Audi's GFRP springs will be... the Sogefi Group, the parent company of Allevard Rejna who build Renault's composite springs. Oh. Will there be some slightly more advanced tech used as the parent company? Anyway, Sogefi's latest press release adds further benefits from the reduced mass, including a slight drop in CO2 (0.5g/km) on the road. Given the springs will first be used in an Audi 'upper mid-sized model' (so we'll assume A4/A6), the promise of 'more precise driving' is welcome. They're aren't known for dynamic prowess so it will be interesting to test those when they arrive later this year.
Original story, has reported 30/06/2014:
Is Renaultsport out on a bit of a personal quest to wind up Dr Hackenberg and the other engineering titans at the VW group? Nicking the FWD 'ring record and moral high ground from SEAT probably rankled, the Megane 275 Trophy-R's use of composite springs among the much publicised technology that enabled it to do so. Slightly taking the gloss off Audi's announcement today it'll be using similar components on an as-yet unnamed 'mid-size model' later this year.
The Megane's composite springs from French firm Allevard Rejna are among the features setting the limited-run special apart from the regular 275 Trophy. Renault claims corrosion resistance and a subsequent longer lifespan alongside a 2kg weight saving as key advantages, saying it is "once more demonstrating its avant-garde approach with this solution, which is new on this type of vehicle." On Allevard's Sogefi Group parent company website it claims additional advantages, including environmental benefits from less energy intensive production, reduced susceptibility to catastrophic failure and even improved NVH.
Damn those pesky French again
So it's avant-garde versus the old Vorsprung Durch Technik then, Audi's unnamed Italian supplier developing a comparable GFRP (glass fibre reinforced polymer) spring with exactly the same claimed benefits. A steel spring for the car on which they'll feature would weigh 2.7kg, against the 1.6kg of the new GFRP one. And these savings contribute to reduced unsprung weight too.
How are they constructed then? Over to Audi. "The core of the springs consists of long glass fibres twisted together and impregnated with epoxy resin. A machine wraps additional fibres around this core -- which is only a few millimetres in diameter -- at alternating angles of plus and minus 45 degrees to the longitudinal axis. These tension and compression plies mutually support one another to optimally absorb the stresses acting on the component. In the last production step, the blank is cured in an oven at temperatures of over 100 degrees Celsius."
The press release continues, "The GFRP springs can be precisely tuned to their respective task, and the material exhibits outstanding properties. It does not corrode, even after stone chipping, and is impervious to chemicals such as wheel cleaners. Last but not least, production requires far less energy than the production of steel springs."
So there you go. Faster, smoother, greener and safer it seems the cure to all our motoring ills wasn't electric motors after all - it was composite springs. Who knew?