Rumours in Italy say engine designer Luca Marmorini has devised an unique system that stops the flow of fuel when the driver is not accelerating, improving not only fuel consumption but also the effect of engine-braking.
Also attracting attention at Jerez were Ferrari's airboxes and sidepods, amid suggestions the Italian marque is ahead of the game in the challenging area of cooling the all-new engine, turbo and energy-recovery systems.
When asked about the Ferrari layout, Mercedes' engine boss Andy Cowell told Auto Motor und Sport: "Cooling has become such an important issue, both for power and for the aerodynamics, so a lot of research has gone into this field."
Meanwhile, McLaren's Jenson Button has said he was impressed with how all the Mercedes-powered teams - including Force India, Williams and the Brackley based works outfit - have worked together in the new V6 era so far.
"While we are here to fight each other as teams," he is quoted by the Mirror, "the more information we can share in the next weeks or months can really help us.
"So we are all in good shape if we continue like that," Button said.