The year of 2008 could not have started, in the automotive world, with a bigger bang. Audi would take to the Detroit Motor Show — which is always held in the first days of the year — a prototype R8 that would shake the foundations of all beliefs about pure sports and supersports. The exposed Audi R8 was equipped with a huge V12 block… Diesel!
Can you imagine the shock waves and amazement? A Diesel super sports car?!
The dissonant voices asserted that a Diesel supercar was an absurd idea. Contextualizing the presentation of this model, it was not at all...
This was 2008 and not 2018 (NDR: at the date of original publication of this article).
The diesel engine was the car's best friend. Diesel engines were being sold more and more, accounting for nearly half of sales in the European market, and Audi in particular had already racked up two victories in the 24 Hours of Le Mans with the Audi R10, a prototype Diesel — an unprecedented feat. And it wouldn't stop there, totaling eight Le Mans victories with diesel-powered prototypes.
It was this push, in the market and in competition, that allowed Diesels to be seen as more than just fuel-efficient engines — at Audi, Le Mans prototypes were technological showcases that were reflected in their road cars. A remarkable evolution, which extended to all car brands.
Despite the “demonization” that they are subjected to today, it is important not to forget the importance and meaning that Diesel engines once had.
the rumors
In 2006 Audi dared to launch a mid-engine rear sports car, the R8 — a junior supercar, as some in the press called it. The unique look, dynamic balance and excellence of its naturally aspirated 4.2-litre V8 — 420 hp at a heady 7800 rpm — have quickly made it one of the most sought-after Audi and sports cars of the moment.
Developed in socks with the Lamborghini Gallardo, it was an unprecedented proposal in the rings brand. It represented the brand's pinnacle on several levels, which quickly sparked rumors: with the Le Mans victories, would Audi capitalize on its competition success with the launch of a supercar Diesel?
Audi R8 V12 TDI
That would never happen, many claimed. A diesel engine powering a supercar? It didn't make sense.
The shock
And we returned to Detroit in early 2008. Amidst a smokescreen (not from the engine) came the Audi R8 V12 TDI Concept — later renamed the R8 Le Mans Concept.
It was clearly an R8, despite distinct bumpers, flared side intakes, and a NACA entry (it gets its name from being developed by the National Advisory Committee for Aeronautics) at the top for engine cooling. And the name was not deceiving, Audi presented a super sports Diesel.
Instead of the V8 Otto behind the occupants there was a 'monster' V12 Diesel, the largest so far placed in a light car: 12 cylinders in V, as in the most noble of supersports, 6.0 l of capacity, two turbos, 500 hp and thundering 1000 Nm… at 1750 rpm(!). And, imagine, mated to a manual transmission.
With numbers like these, it's no wonder the larger air intakes for the engine.
Contrary to rumors, the engine was not a derivation of the 5.5 l V12 of the competition R10, but shared with it much of the architecture and technology employed.
According to the brand's numbers, the Audi R8 V12 TDI, with four-wheel drive, would be able to accelerate up to 100 km/h in 4.2s and reach a maximum speed of 300 km/h — not bad…
technical complexity
The Audi R8 V12 TDI Concept would appear again a couple of months later at the Geneva Motor Show, replacing the original gray color with a much more vibrant red. More importantly, it was a working prototype, closer to production — some journalists were even able to drive it.
The rev counter with "redline" at 4500 rpm… in a super sports car!
But it quickly became clear that this "laboratory experiment" would know little and the culprit was the engine, or rather its size. The V12 block was longer than the V8, so it “invaded” part of the cabin to fit.
And it left no room to install any of the Audi R8's transmissions — what's more, none of them were prepared to withstand the massive 1000 Nm of torque from the colossal block.
They had to resort to a more compact Audi A4 transmission to allow the Audi R8 V12 TDI prototype to ride, but like other transmissions, it was unable to handle the V12 torque, so the torque was artificially limited. Nm, little more than half.
the beginning of the end
As you can understand, the task of fitting a V12 engine into a body that was not intended to receive it, proved to be complex and expensive. The final step in production would require reconfiguring the R8's rear section and creating a transmission from scratch that would not only fit the limited space available, but also support 1000 Nm.
The accounts just didn't add up — the expected production figures for this 'heresy' with wheels did not justify the necessary investment. Furthermore, some markets essential to its success, such as the US, where Audi sold a third of all R8s, were not at all receptive to diesel engines, let alone a supercar with that type of engine.
After performing in Detroit, it got a new color and name for Geneva — Audi R8 TDI Le Mans Concept
Audi ended the project definitively — the diesel supercar would be confined to the realm of probabilities. It was the end of the super sports car Diesel, but not the end of the mighty block.
It wasn't the end of the colossal V12 TDI… and thankfully
Rejected in the R8, the V12 TDI engine found space in a more appropriate body. The Audi Q7 V12 TDI, which also began marketing in 2008, has become the only production car equipped with this powertrain.
It is still the only light car to have had a V12 Diesel under the hood — with the same power and torque figures as the Audi R8 V12 TDI — and a ZF six-speed automatic transmission, reinforced to guarantee its durability in the task of dealing with 1000 Nm.
After all these years it continues to impress…
