Porsche had 'difficult discussions' on turbocharged 911

The long-time development chief of the Porsche 911, August Achleitner, has revealed there were a series of “difficult discussions” within the company before the green light was given to turbocharging the entry-level Carrera models.

But the Austrian, who has overseen the development of the iconic rear-engined sports car since 2001 and worked on it since joining Porsche in 1983, says he is now at peace with the move from natural aspiration to forced induction that will soon encompass almost the entire 911 range, bar the hard-core GT3s.

The new 9A2 3.0-litre bi-turbo flat six that powers the updated ‘991.2’ 911 Carrera and Carrera S coupe and cabrio in different states of tune were shown off publicly for the first time at last week’s Frankfurt motor show.

The new engines, which make more power and torque and are more fuel efficient than their naturally-aspirated 3.4-litre (Carrera) and 3.8-litre (Carrera S) predecessors, are fundamentally all new and will also provide significant tech towards the four-cylinder engines destined for 2016’s 981.2 Cayman and Boxster.

The 991.2 911s start rolling out in Australia from March next year, accompanied by significant price hikes.

“I can promise you we had several difficult discussions within our house because everyone in the company loves the normally aspirated engine,” Achleitner told motoring.com.au at the 991.2’s reveal. “Let me say they are almost perfect; the 3.8 litre, I love this engine, it is one of the best in my own opinion.

“So the emotion had been quite high because we had been completely convinced altogether that if we make a change to a turbo engine then the new turbo engines have to be better than this 3.8.”

As recently as 2012 Achleitner told motoring.com.au that he was no fan of turbocharging for the 911, a move that was being increasingly mooted as emissions and fuel economy targets became tougher.

He told us then: “We try to keep it (turbo) away as long as possible. Maybe it is necessary one day.”

But Achleitner revealed last week his personal conversion came in early 2014 when he was part of test ride and drive in southern Africa that include the nat-atmo 911, the new turbo Carrera and the mega 3.8-litre 911 Turbo model.

“You could absolutely feel this car (991.2 Carrera) is much, much faster than the standard 911,” he recalled.

“Especially on country roads, because you do some acceleration out of the curves and you don’t need to come up to high revs – let me say more than 4000 rpm. It just pushed you ahead from 2000rpm and that makes the car much more faster, much more easier and the gap to the big turbo is smaller than before.”

Achleitner said two of the key issues to address in the shift to turbocharging were lag and the engine’s sound.

The former he dismissed as being relatively easy to resolve thanks to the large capacity of the standard engine and Porsche’s set-up of the two small capacity turbochargers.

Making the turbo 911 sound right was a harder challenge though.

“It took a long time till we came to the result which now we are satisfied with the sound,” he admitted. “So we had to bring in a second sound symposer -- today’s normally aspirated engines have just one connected between the intakes and the cockpit of the var.

“Now we use two of these elements which have a different layout because it had been necessary.

“The turbo engine itself does not produce these hard changes in the air movement within the air intake system which you can very well use for the sound and is exactly what you want to hear. It is more damped within the turbo.

“So we had to find the right place from where we take the vibrations in the air and transit it to the interior. We are satisfied and it is working very well.”