Driven: 2008 Audi R8 V12 TDI Le Mans Concept
By by: George Achorn
Mar 14, 2008, 11:08
Itís morning at a retired airport ground that adjoins the Sebring International Raceway. Iím in town for the American Le Mans Seriesí 12 Hours of Sebring race, and word from Audi was that we might take a quick spin in their diesel-powered, mid-engined R8 supercar shown just last week in Geneva and planned for display here at the race tomorrow.
The crimson R8 V12 TDI "Le Mans" sits before me on the tarmac, awaiting some quick frottage - just enough to see the potential, though not enough to jeopardize Audiís one-off prototype. The car is still a concept, which means two things: First, it's hasn't undergone the battery of tests that production cars do and, second, its build cost was more than the $1.2 million my insurance company says my life is worth. "Nothing over 50," say the Audiís handlers. Good idea.
"Meh", you say. "What good is such a limited drive?" But, let me ask you - paraphrase rather - in my best Ferris Bueller voice: ďIf you had the keys to a car like this, would give them back? I didnít think so.Ē
It was two years ago at this very track, on this very race weekend that Audi raced into motoring history, driving home a maiden win for the all-new R10 V12 TDI racecar. Only three years, yes, but in that time Audi has put into production the mid-engined R8 and also a V-12 TDI engine. Sadly, the two are not yet combined in actual production form, but you can guess thatís the intention when you consider the scarlet wedge that's basking in the south Florida sun.
Even before this particular prototype was color-changed from satin silver for Detroit to brilliant red for display in Geneva, it was clear this was no run-of-the-mill R8. This design study is more aggressive at both front and rear, with more aluminum brightwork - from the unsplit honeycomb grille to trim on the lower fascias and the wedged-out, supercooling version of the R8ís trademark sideblade. The latter is an element weíll likely see carry over on the next production variant sporting Audiís V-10.
The roof is transparent glass, split by a singular large NACA duct that channels air into the V-12ís engine bay, also harking back to a trademark design cue of the 1991 Audi Avus concept car.
This V12 TDI R8 resets the bar, and makes the high-revving 4.2-liter production R8 look somehow lesser; itís like a Hemi hogging the spotlight from the 340 Six Pack in vintage Dodge Challengers.
Like the Hemi, the V12 TDI is a heavy brute of an engine. Unlike the Hemi, this isnít a homologation mill - something you might be wondering if you are casually aware of the R10 racecar. Both the R10 and the R8 Le Mans study have a V12 TDI, but the similarities begin and end there. The Le Mans' 6.0-liter street engine is about 150 hp shy of the 5.5-liter race engine, but with a rating of 737 lb-ft of torque from only 1750 rpm, itíll shred pavement like a Kenworth hauling a double-wide on snow chains. Weak it is not. The Germans on hand tell me that itíll also hit 62 mph in 4.2 seconds under full power, with a top speed of 186 mph, before pausing to add that I will not be getting anywhere near that today. The engineís only running 442 lb-ft today - an effort to keep guys like me from damaging the thing and to increase life of the experimental transmission thatís been custom-built within a case from the Audi A4 parts bin.
Looking at this car in the metal, we have no doubt about criticsí potential concerns over its environmental impact. For these people, weíll point out that the R8 V12 TDI will provide 24 mpg and meets the upcoming 2014 Euro 6 emissions standards, thanks to Audiís particulate-catching AdBlue system.
Sliding onto the carís seats, perforated all-black hides with red R8 logos, I'm surrounded by enough aluminum accenting to boost Alcoaís share price. What little storage space there was behind the seats is gone - the firewallís been moved forward to accommodate the V12ís length.
The most noticeable change for the driver is right under my nose - a new flat-bottomed, partially aluminum steering wheel with a magnesium core. The anodized red starter buttonís moved from the dashboard to the 3 oíclock spoke, as is a dial control for the carís dynamic chassis. Turn the knob to Sport Mode and, in addition to firming up the electrically adjustable dampers and recalibrating the throttle map, the instrument lighting goes from white to red.
This R8ís navigation isnít just for finding truck stops with low sulfur diesel either. It also has track layouts and a lap timer function, as well as real-time data like boost pressure and centrifugal force - both lateral forces and acceleration/braking forces.
For now though, to hell with the technical details. Iím told I have exactly one half hour with this prototype. All I need is one hand on the wheel, one on that gated shifter - yup, itís a manual - and feet positioned for quick use of those three alloy pedals: clutch, throttle, and the stoppers - carbon ceramics, to be precise.
Thereís no key and no ignition for this prototype. With a foot off of the clutch, I press the satin-red starter button on the steering wheel once and the car powers up. Depress the clutch and hit it a second time and the thing fires to life. Itís a quiet and subdued rumble with a touch of diesel clatter. If youíve watched Audiís R10 slingshot quietly down a straight at an American Le Mans Series race, you get the idea.
The noise is almost unexpected in this prototype engine. Itís not chattering like a Cummins Ram, but it is more noticeable than Audiís whispering production TDI engines as seen in the on-sale-soon Q7 3.0 TDI.
Engaging first gear, you hear the trademark snikt as the shifter enters the gate. Clutch feel seems decidedly production - linear and light. First gear is short and the TDIís redline is shorter, so Iím through it quickly even though thereís little anger in my launch.
Heavy into the pedal, the sound is like nothing Iíve ever heard. Thereís the churn and muffled roar of twelve firing cylinders right behind your head, almost drowned out by the vacuum of air sucking into the carís enlarged intakes.
Our test track is big and straight - a cement landing strip used during World War II for B-17 Bombers. Grass is growing between the aging cement slabs, in joints that thump smoothly under the R8. Audi staff have done their best to clean an even narrower path down one straight and Iím asked to do my best to stick to that area.
Cornering in this prototype is limited to spirited turnarounds or zig-zagging down the strip like a racer trying to keep tire temps up while lapping behind a pace car. I note the carís added girth over the V-8 R8 I just drove over to this abandoned stretch, but this is still no brick sled. The V12 TDI prototype has multi-mode Audi Drive Select system and more aggressive tune.
Racing (if you can call 50 mph racing) toward the end of the runway, rev-matching for a downshift causes me to pause momentarily. The revs go up easily, but redline is nearly half that of the gas R8, making me think twice as I go down a gear and try to re-set my brainís ear-based tach from R8 V-8 to R8 V-12.
Down at the end of the airfield, I swing the R8 around to head back and bring the car to a stop. Now itís time to launch it in earnest.
Maybe itís my knowledge of the cost of this car, or my empathy for the job security of the engineer riding with me, possibly the well-being of the A4-derived gearbox. But I decide to abandon any idea of sidestepping the clutch and churning up a rooster tail of B17-era tarmac. Itís just as well, as even a hard, controlled launch in first brings you to redline in a ridiculously short amount of time.
Snikt. On to second. Power hits you like a brick wall, red stone and mortar smacking you upside the nostrils the whole way down the line. Itís that linear, making the stock R8ís 4.2-liter V-8 feel like small displacement. The eight is almost Honda-like in comparison, with the need to keep the revs high - not so with the V-12.
Power delivery is something akin to what Iíve felt from the big W-12 twin turbo fitted in the Bentley Continental GT. It simply doesnít feel as fast as the R8 4.2, but the speedo says it is. Delivery is smoothly brutal and that makes gauging pace hard to do. The low noise level, save intake suckage, is another factor. Itís there but not snarling like the R8 4.2.
Iím on to third and I want to keep on it, but my co-driver (read: minder) starts motioning his hand down. Alas, Iím caught red-handed, but it is what it is.
Iíve driven the Audi R8 V12 TDI and even wrung it out a bit. When I run into Audi Sport team driver Allan McNish at the track, he mentions he hasnít been able to do more yet than sit in the car. Alas, while talking to Allan thatís my only bragging right. Heís nabbed pole for the 12 Hours and I think thatís trump. Oh yeah, heís also got a couple Le Mans wins under his belt.
As for the R8 V12 TDI, Audi executives refuse to be pinned down on actual production of a car such as this. If they did, theyíd have instant credibility given their diesel wins in races like Sebring and Le Mans. The current R8 is sold-out for months, with V-10 and open-top variants already in the pipeline. Itís possible that an R8 V12 TDI could be sold, or Audi could wait until the carís successor - presumably something with a longer wheelbase to accept this big engine. For now, time will have to tell; Audiís staff isnít saying boo.
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