SPY PICS: New Audi RS 4 likely to get Porsche V6

The original RS bahnstormer, the Audi RS 2 Avant, was a car co-developed by Audi and Porsche and now, it seems, that collaboration is recommencing.

The new 2017 Audi S4 gets a new 3.0-litre petrol V6 engine with a single turbo, and its development had some input from Porsche engineers. The 2995cc mill pumps out 260kW and 500Nm in the S4, giving it similar pace to the previous RS 4, with a claimed 4.7 second 0-100km/h sprint.

But the new RS 4 is tipped to an altogether crazier, twin-turbo 2.9-litre petrol V6 that been almost entirely developed by Porsche, and debuts in the new Panamera four-seat cruiser that launches Down Under this week.

By adopting modular engine architectures car-makers can reduce development costs and, to put it crudely, the 2.9-litre Porsche V6 is effectively the company's new 4.0-litre V8 minus two cylinders.

In the Panamera, the slightly smaller 2894cc V6 powerplant belts out 328kW (440hp) at 5650rpm and 550Nm of torque over 1750-5500rpm.

Because the V6 has two turbochargers there's more scope for big power gains, which could be one reason Audi Sport will use the 2.9-litre Porsche unit and not the 3.0-litre single-turbo jobbie.

To compete with the Mercedes-AMG C 63, BMW M3 and Alfa Romeo's new Giulia QV, the new RS 4 will need to pump out at least 350kW and 600Nm, which would make it the most powerful RS 4 ever and capable of accelerating to 100km/h from rest in around four seconds flat, with a little help from a new-fangled quattro AWD system.

Audi Sport CEO, Stephan Winkelmann, was in Australia for the 2017 Bathurst 12 Hour race and although he wouldn't confirm if the Audi RS 4 will switch to the 2.9-litre Porsche engine, he wouldn’t rule it out.

"You know one of the secrets of small companies, and Audi Sport is a small company, [is that] if you want to stay successful you never speak about the future," he grinned, after motoring.com.au asked point blank if the Porsche V6 is lurking under the next RS 4's bonnet.

Either way, the new RS 4 is widely expected to break cover at the 2017 Frankfurt motor show in early September. The car has already been spied undergoing winter testing in recent months and looks production-ready, with its blistered wheel arches and cannon-like exhaust outlets on proud display.

The RS 4 has been a popular vehicle in Australia and the new model is likely to be its strongest seller yet, even with an expected $160,000 price tag.

"The previous RS 4 sold better than the S4, despite being on sale for a shorter time," said Peter Strudwicke, Audi Australia product planner for the A4 and A5 model ranges.

He wouldn't be drawn on the Porsche-Audi engine collaboration for the new RS 4 either, diplomatically stating: "I can't talk about the new RS 4 at the moment".

However, when asked if customers would be put off by the RS 4's ditching of a V8 engine, Strudwicke said: "It's the entire package that appeals to customers".

"Clearly RS 4 and RS 5 have been very successful and we'd hope that success would continue."

The RS 4 has been a long-time coming but it's unlikely to be the only Audi RS model to get the lusty new Porsche V6.

Winkelmann said a new RS vehicle will be revealed at the 2017 Geneva motor show in March but that it won't be the RS 4. Expect the all-new RS Q5 to be that vehicle, which will provide an insight into how Audi will tune Porsche's 2.9-litre biturbo V6.

"The present is bright enough so we have to live it. Geneva is in front of us -- we'll have a launch there which is going to be very important for us … You will see very shortly what is going to happen," he said.