It's not 4.0, it's 40. And it's nothing to do with litres or cylinders, it's an entirely arbitrary thing come up with by Audi to denote power bands, something like 25-30-35-40-45-50-55 from lowest to highest. I'm guessing the idea is to have a single system regardless of the type of engine/power source employed, but it certainly confused me when I first encountered it.
It's not 4.0, it's 40. And it's nothing to do with litres or cylinders, it's an entirely arbitrary thing come up with by Audi to denote power bands, something like 25-30-35-40-45-50-55 from lowest to highest. I'm guessing the idea is to have a single system regardless of the type of engine/power source employed, but it certainly confused me when I first encountered it.