It has yet to push a single RS 3 Sportback across a showroom forecourt, but Audi has promised even more power and performance from the next generation TT RS. Sources at Audi said this week that the hottest version of the just-launched small coupe would come with more than 300kW – well up on the 270kW in the new RS 3.
The two cars shared the same turbocharged, direct-injection, in-line five-cylinder engine in the superseded generation, but this time around, the coupe will receive significant upgrades. It will get to 100km/h considerably quicker than the 4.3 seconds it takes the five-door RS 3, although it is expected to share the hatchback’s 280km/h optional top speed.
While Audi's go-fast quattro GmbH division head honchos, Stephan Reil and Heinz Peter Hollerweger, refused to talk on the record about the fast-five coupe, insiders insist the car will have almost 40 horsepower more than the RS 3. They also insist it will use the extra power to knock on the door of the 4.0-second barrier for the sprint to 100km/h.
Reil – whose penchant for short-sleeved business shirts and horn-rimmed glasses leaves him looking perilously close to Michael Douglas's William Foster character in Falling Down – wouldn't even confirm the obvious inevitability of an RS version of the TT, much less how much power it would have.
However, he said, there would need to be a lot of work to get more performance out of the RS 3 motor. “If you look at the performance curve, there are not many engines out there that can deliver this much torque (465Nm) at such a low rpm (1625rpm),” Reil added.
“But to do that, the car is at the limit of the speed of the turbocharger now. The turbocharger is a relatively small one, for reasons of throttle response, and the performance in the RS 3 is at the limit of the rpms the turbocharger wheels can do in production.” Nor would electronically boosting the crankshaft or turbocharger help a TT RS to climb beyond 400 horsepower.
“Well, the e-boosting we have shown on the RS 5 concept works very well with a diesel, but it’s not as effective on a gasoline engine,” Reil said. “You would also have to package the system, including an additional 48-Volt electrical system and another fast-discharge lithium-ion battery and that would not be practical in a car the size of the TT.”
That leaves a TT RS looking at a larger turbocharger with more scope for high-rev boosting to increase its mean effective cylinder pressure. It would also give the TT RS a different character to the new RS 3, whose power delivery is a little more about an early punch with the boost tapering away as the revs rise.
Sources say the TT RS torque curve will still be strong down low, but its peak will arrive at least 400rpm upstream of the RS 3 curve, while it will stretch its legs with a performance curve that prioritises greater strength at higher rpm.