We don’t yet know if the next Audi RS4 will come to the US, but whoever gets it could find an electric turbocharger under the hood according to a report in Auto Express. The 4.2-liter V8 that has served for two RS4 generations is retiring from the line, replaced by a twin-turbocharged version of the supercharged 3.0-liter V6 used in the S4. But instead of using two sequential turbochargers – a smaller one to eliminate lag while a larger, more powerful turbo spools up – batteries charged by brake regeneration could power a first-stage electric turbo.
The idea hasn’t been publicly appointed for a particular model, as Audi’s technical chief Ulrich Hackerberg has said that due to expense, that kind of setup “would only be used be used on the very top end models.” Since the technology cuts down on the use of exhaust gases, it would also also help in markets like Europe where CO2 emissions are a factor.
No matter whether it benefits from all conventional or some electric boost, the horsepower number for the twin-turbo V6 will be more than 420 hp but less than 503 hp, the rating of the V8-powered Mercedes-Benz C63 AMG. Auto Express believes Audi will want to maintain the power gap between the 333-hp S4 and previous, 444-hp RS4. With Hackenberg saying the new S4 will make more than 350 hp, that gets the coming RS4 up to at least 461, but AE figures it “could deliver as much as 480 hp.” We’ll find out sometime after the S4 launches next year.