In an interview with Dr Ulrich Hackenberg, Audi’s Head of Technical Development, Auto Express has come to find out that the upcoming Audi RS4 will indeed be a turbocharged, but that it will also use n electric turbocharger. This comes hot on the heels of news that the standard S4 will also use a turbocharged V6 and not the same 3.0 liter Supercharged V6 as the outgoing model. So the engine could be the same, just with extra power for RS duty.
The Audi RS4 will have a twin-turbo setup, however, one of the turbos will be a smaller one and be powered by a battery instead of exhaust gasses. This allows for instantaneous spooling, without the need for the revs to climb to get boost. This small electric turbocharger will then give way to a larger, more conventional turbocharger, once the rpms start to rise. The battery which will power the electric turbo will be charged by a generator which will gather power recouped from regenerative braking. This will create an extremely efficient system and help maintain reasonable fuel economy.
This setup not only eliminates turbo lag completely, but it also allows for the upcoming RS4 to have somewhere in the ballpark of 500 hp. During the interview, Dr. Hackenberg said that the RS4 won’t match the current Mercedes-Benz C63 AMG’s 503 hp, simply because “that car has eight cylinders.” However, Hackenberg claims that Audi would like to keep a similar power gap between the S4 and RS4 to how it currently stands, meaning that the next-gen RS4 could have around 480 hp. This also means that the standard S4, which could possibly use the same engine but with one conventional turbo, should have in excess of 350 hp.
Hackenberg also hinted that this upcoming engine could also be fitted in the Audi R8. “The R8 is a V10 supercar, there will not be a V8 version again. But there are some markets which demand a smaller capacity engine for that car.” Though he claims that the V8 will never return in the R8, the need for smaller capacity engine could make Audi consider this V6, with its exotic turbocharging setup and instantaneous throttle response. Given that the electric turbo setup is very expensive, far more so than a conventional twin-turbo setup, only the high end Audis will receive it, which fits the bill for the R8 pretty well.
We won’t know for sure, which engine will embody the Audi RS4 or the S4, but we may find out soon as Audi might debut the upcoming Audi S4 at the Frankfurt Auto Show. Hopefully we’ll get some more info then.