In an interview with Autoblog at the TT RS’ launch, the man in charge with engineering at Audi’s Quattro division reconfirmed the demise of the naturally-aspirated 4.2-liter V8 for next RS4 and RS5. Instead, the cars are going to downsize to a turbocharged V6, but it won’t be Audi’s new 3.0-liter from the latest S4 and S5 models.
The RS4 Avant, RS4 Sedan (yes, it’s coming back), RS5 Coupe, and RS5 Cabriolet will be motivated by the Panamera’s biturbo 2.9-liter V6 mostly developed by Porsche with some input from Audi. It’s also set to power the entry-level R8 due to arrive in United States in 2018 based on a leaked roadmap, following what will likely be a Euro launch in the second half of 2017.
Details about output have not been disclosed, but in the Panamera 4S the engine is good enough for 440 horsepower (324 kilowatts) at 5,650 rpm and 406 pound-feet (550 Newton-meters) of torque attainable from 1,750 rpm. It remains to be seen whether the future RS-badged cars from Audi will have the exact same output, or if the high-performance models will get a different tune of the engine.
And now for the bad news, Stephan Reil revealed development of the turbocharged 2.0-liter, four-cylinder engine with 420 horsepower has been terminated. Introduced back in 2014 with the spectacular TT Quattro Sport concept pictured above, the powered-up motor was rated at a fantastic 420 hp (309 kW) at 6,700 rpm and 331 lb-ft (450 Nm) from 2,400 rpm. One model that was supposed to get the beefy 2.0-liter was a production version of the VW Golf R400 concept, allegedly called “R420” to reflect the engine’s muscle.
While the engine itself will not find its way underneath the hood of a road-going car, the turbo 2.5-liter unit inside the 400-hp TT RS actually has more in common with the four-banger rather than its predecessor. Reil says only the bore and stroke are taken from the old five-cylinder engine, while a lot of the geometry is derived from the now defunct 420-hp four-cylinder motor.
Quattro’s development chief went on to specify the engineering and production costs of the four-cylinder engine would have been higher for Audi compared to the larger unit. In addition, Reil said at the end of the day that would still have been a four-cylinder unit, so it would have had a lower perceived value than the new 2.5-liter mill.