Despite previous assurances that Quattro had roles for both the EA888-based engine and Audi's wildly charismatic 2.5-liter, five-cylinder motor, post-Dieselgate reality has killed the smaller engine. "The 400-horsepower EA888 engine is dead," Reil said.
The EA888 engine was conceived and developed by the same man behind AMG's powerhouse 2.0-liter four. Friedrich Eichler left AMG to become the Volkswagen Group's gasoline engine development go-to guy, and he was confident the 420-hp engine could be turned into a production car quickly, as was then-Audi development boss, Ulrich Hackenberg.
It was even suggested that because the EA888 engine family bolted straight into the Volkswagen Group's ubiquitous MQB small-car architecture, the little powerhouse could be cheaply and quickly dropped into any of the company's cars that needed an image boost.
Since then, Quattro has elevated the five-cylinder motor, switching it to an all-alloy block with a magnesium oil pan to cut down its weight while boosting its power and torque levels. Where the four-cylinder engine was shown with 420 hp and 332 lb-ft of torque, the production version of the TT RS's new five-cylinder engine totes 400 hp and 354 pound-feet of torque. The smaller engine's proponents claimed a 0-62 mph acceleration figure of just 3.7 seconds for the concept TT that carried it, and it might not be a coincidence that the all-new TT RS claims exactly the same figure.
The 2.0-liter motor had a torque peak that arrived at 2,400 rpm and began to taper off at 6,300 rpm, while its power apexed at 6,700 rpm, thanks in part to a turbocharger that could feed it up to 1.8 bar of air. Flip to the TT RS' data and you're looking at more torque at lower revs and a touch less power, but at higher revs.
That's not a lot of wriggle room for the concept engine to operate, especially when the perceived value of the five-cylinder engine is higher than the four, and the four's development and production costs would be higher than the five's. "If we go for the four, to have that specific power output from a 2.0-liter, the engine is unbelievably expensive and then we still have only a four-cylinder engine," Reil insisted.
He denied the four-cylinder's power output lit a fire under Quattro's engine development team, but the TT RS's power output jumped from the TT RS Plus's 360 hp to the new model's 400, and it's now toting twice the torque output of the original Quattro coupe. "No, that's nothing to do with what we've done to this engine. We would have done this anyway. People love the sound of the five-cylinder engine," he said.
It also didn't help the smaller engine's future that it was developed in Wolfsburg, not Neckarsulm, and even Reil admits the new TT RS 2.5-liter engine borrows shares significant ideas with the concept car's mill. It actually owes more to the four-cylinder engine than to its own five-cylinder predecessor. "The bore and the stroke are the same as the old engine, but everything else in the five-cylinder is new. They don't share a single bolt," he said. "The parts (in the five-cylinder motor) are different to the EA888 from that car, but a lot of the geometry is similar."
There is another engine in the family that has squeezed the 2.0-liter four into the field of extravagant frippery, and that's the 2.9-liter (codename KoVoMo) V6 turbo motor jointly developed by Audi and Porsche (but mostly by Porsche). Completely different from the 3.0-liter V6 Audi already runs, the new V6 engine is fitted to the new Panamera and will find its way into the RS4 and RS5. It will also become the entry-level engine for the R8 supercar and effectively replaces Audi's old 4.2-liter naturally aspirated V8 engine. All of that hurts because it means a tantalizing 2.0-liter, 420-horsepower R8 baby supercar will never happen, even though its lighter weight promised even better handling than the current V10.
Hackenberg even suggested there were few development impediments in the way of the EA888 thumper. "It can go into production nearly how it is in the TT Quattro Sport Concept," Hackenberg insisted last year, before his suspension over the Dieselgate emissions-cheating scandal at the Volkswagen Group. "For production, we would have to change the cylinder head, because the EA888 has the exhaust manifold in the cylinder head now. With this engine and its output, it produces too much heat in the head to keep it like that, so we have to change it. But, apart from swapping in some stronger parts, it can still be made within our production system."
That might all have been a slight (and deliberate) under-estimation, because the 331-pound engine needed custom-built aluminum pistons with integrated cooling channels, an ultra-high-strength crankshaft and a high-strength cast-alloy crankcase.