The once mighty naturally-aspirated units such as the 6.2-litre V8 in AMG products or the 5.5-litre V8 alongside a host of non-turbo six cylinder engines are all finished, according to Bernhard Heil, the head of Powertrains at Daimler (Mercedes-Benz parent company).
“I personally believe that [the naturally-aspirated engine] is a done thing.” Heil told CarAdvice at last week’s Mercedes-Benz technology day in Stuttgart.
Heil says that the next-generation of 2.0-litre four-cylinder turbocharged engines will be able to achieve 100kW/L in non-performance trim (the current 2.0-litre in the A45 AMG makes 285kW), while being able to achieve the same result with a naturally-aspirated engine in accordance with the ever-tightening emission regulations is not possible.
“If you’re talking about 200kw for a [2.0-litre] four-cylinder engine, you will end up in a situation that you will need a V8 4.0L naturally-aspirated engine - and you will never end up in real-life fuel economy with a V8 offering comparable numbers to a four cylinder," he said.
Even so, Heil admitted that from an emotional perspective, naturally-aspirated engines are hard to replace.
“My heart is telling me a completely different story. I love those big V8s and big V6s, but on the other hand the performance of those high-density four-cylinder engines is incredible.”
As for what that means for enthusiasts that adore the sound of naturally-aspirated engines, something that is muffled by the use of turbochargers in new Mercedes-Benz cars, Heil believes things will improve.
“That is a question of philosophy. We can find technology solutions with synthetic sound that is not different [to a naturally aspirated]. That is not typically our way that we are doing that, because a Mercedes should not produce V8 sounds if there is a four-cylinder engine - it is not in-line with our understanding. We are working with our four-cylinder sound to make it even more attractive and we will find more solutions.”
Arch-rival BMW also sells no new cars with a naturally-aspirated engine, although fellow German manufacturer Audi still sells its halo car, the Audi R8, with a naturally-aspirated V10.