Audi 'Did Not For a Single Second' Consider a 4-Cylinder RS 5

• The new RS 5 was never going to have four-cylinder power, though a PHEV wasn’t the only solution Audi considered.
• A "non-plug" hybrid version of the RS 5 was considered but ruled out, as it added weight without performance.
• Audi bosses praised the dynamics of the four-cylinder Mercedes-AMG C 63 but said a "step-by-step" approach is better.

Audi bosses praise four-cylinder C 63, but say customers weren't ready

While Audi decisively swerved away from downsizing or going fully electric, Michl praised the engineering of the four-cylinder C 63 as being ahead of its time.

"[AMG] has fascinating products, and the [four-cylinder] C 63 drives really well ... the car is amazing, honestly," Michl told Edmunds. "We were impressed by the technology that was implemented there, [but] at the end, between a technological solution and the customer’s decision, sometimes there is a bit of a gap."

"You have to listen to the customer, and obviously, it is a step-by-step approach," Michl said.

Mercedes-AMG has confirmed it will shortly replace the four-cylinder C 63 with a mild hybrid inline-six to be badged as the C 53. BMW has already confirmed its next-generation BMW M3 will retain six-cylinder power, albeit alongside a fully electric version designed to appeal to markets with tight emissions rules.

Non-plug-in RS 5 was considered, but PHEV's performance edge was the clincher

Bamberger said Audi briefly experimented with a non-plug-in RS 5 hybrid with a smaller battery and nominal electric range, but its weight was not far off the 5,200-pound spec of the production RS 5 PHEV.

"In the really early phase [of the RS 5's development], we had discussions about whether it was better to come back to a HEV [hybrid] system," Bamberger said. "At the end of the day, we decided that the HEV system is only one side of the coin."

Michl agreed, telling Edmunds that the regular hybrid RS 5 concept “was quite a compromise." Even without the PHEV system, the RS 5 still had to be at least a mild hybrid to pass emissions regulations and that still involved a jump in weight.

"The [extra] weight without the range benefit was not the way we wanted to go," Bamberger said. "The HEV system [weight] can be up to 330 pounds, so it is quite huge, and in my personal opinion, a 6-mile range was not a realistic offer for the customer."

Development drives of the PHEV concept sealed the deal for plug-in power. The RS 5's 400-volt system boosts acceleration but it also feeds a smaller electric motor on the rear axle that drives the RS 5's Dynamic Torque Control system that sends 85% of torque rearward for sensational, sustained drifting.

Audi bosses predict Americans will embrace PHEV in the RS 5, and in future models

Internal Audi policy has hardened against the concept of using different engines for different markets, and with the PHEV system unlocking both smoky drifts and smokeless urban driving, executives see hybrid tech as palatable in North America and Europe despite differences in customer tastes.

"For the U.S., I think [customers] won't exclude electrification if it helps for the drivability, because those guys are absolutely performance guys. I bet they will also love it," Michl told Edmunds.

The Audi Sport chiefs are so confident that PHEV was the right step for the RS 5's V6 engine that they say even if the European market abandoned CO2 regulations, they would still want the plug-in hybrid system in the car.

While Bamberger described the CO2-slashing properties of PHEV as "the main reason" for adopting it, Michl said it was about more than sustainability. "It is not only a CO2 discussion," said Michl. "It is also for the drivability, the performance aspects and the electric torque vectoring, which enables a different kind of lateral dynamics."

Audi won't build non-hybrid versions specifically for the U.S.

Pressed about whether a non-hybrid combustion engine could be a fit for the U.S. market in future fast Audis, Michl said that was unlikely.

"Special cars for single markets [are] a big challenge. You offer a car that matches worldwide. There can be adaptations to a certain extent, but I would exclude a specific technology just for one market."

Still, Audi Sport says it does not rule out introducing a future non-hybrid, pure internal combustion model. "You have to be flexible in your life," Michl said.