George Achorn (Fourtitude) had told me that the V12 can fit in the R8 but due to size and weight of the engine extensive modifications will be needed.

Also cooling is a problem but that can be fixed too.

In other words Audi is already working on the project for the past year or so.

Yannis,you say that all problematic areas with this powerplant to be fitted can be resolved and that is also my opinion..But,would it make any sense to totoally modify R8 just to put this engine under the bonnet ?And what about price of such car ?

It makes sense cause Audi wants to write again the automotive history books with the first diesel power supercar.

The price will be probably outrageous and the production number limited.

An exotic sports car with a diesel? Sounds like peanut butter with jelly to us.

BY JORDAN BROWN, PHOTOGRAPHY BY HEINRICH HÜLSER AND JEFFREY G. RUSSELL
May 2007
Those familiar with VW/Audi’s naming conventions know TDI is the acronym for Turbocharged Direct Injection, the German automaker’s revolutionary diesel power plant that made its debut back in 1990 in the form of an inline five-cylinder powering the Audi 100 Wagon. So the next question is, “An R8 with a diesel?!” In short, yes.
Sources say Audi has a diesel-powered R8 in the works, and we’d like to think they’re right. As far as cutting-edge diesel technology goes, Audi’s one of the best in the biz. Its latest demonstration of spark-plugless prowess came in the form of the R10 TDI race car, winning its very first race at the 12 Hours of Sebring as well as the infamous 24 Hours of Le Mans and the Petit Le Mans. So who better to make a diesel exotic?
The bigger question—especially for us in the U.S.—is why would Audi want to put a diesel in a car that already is so good in its present form? We know, clean diesels have proven they are for more than big pickups and school buses. Europeans swear by them. They would give up anything to pay a measly $3.45 a gallon like we do, while our low gas prices over the years prevented diesels’ torquey richness from being brought to the U.S.
We realize European buyers with $110,000-plus for an R8 TDI are not counting the change in their piggy banks for gas money. So, we suspect that it’s an image thing, or that they are addicted to the torque.
This brings us to the next question: Which engine would Audi use in an R8 TDI? While there are a mess of TDI powerplants to choose from, rumors and our educated guesswork narrows it down to three possible choices. Consider them the good, the bad, and the ridiculously impractical.
All three powerplants can be found in the Audi Q7 SUV. First, the good: the - ONLY REGISTERED AND ACTIVATED USERS CAN SEE ALL LINKS - CLICK HERE TO REGISTER which makes a solid 326 horsepower backed by 561 pound-feet of torque. Next, the bad: the - ONLY REGISTERED AND ACTIVATED USERS CAN SEE ALL LINKS - CLICK HERE TO REGISTER that puts down a very sub-exotic 233 horsepower, although it makes its fair share of torque at 369 pound-feet. Last, and certainly not least as far as sheer power goes, is the ridiculously impractical - ONLY REGISTERED AND ACTIVATED USERS CAN SEE ALL LINKS - CLICK HERE TO REGISTER influenced by our aforementioned friend, the R10 race car. This beast lays out a mind-numbing 493 horsepower and 738 pound-feet of torque.
So naturally our choice would be the 5.9 TDI right? Unfortunately, just as reality strikes us each week when our paychecks arrive, so does it remind us of practicality, and the 5.9 TDI ain’t that. It’s far too heavy for a sports application such as the R8, not to mention with that kind of power Audi may be overstepping its bounds with subsidiary Lamborghini. What a shame. We really wanted to see a car that would literally break your neck under acceleration.
On the flip-side, the 3.0 TDI V-6 seems a little anemic for an exotic—233 horsepower would only cut it in something as light as the - ONLY REGISTERED AND ACTIVATED USERS CAN SEE ALL LINKS - CLICK HERE TO REGISTER but at 3500 pounds, the R8 isn’t what we’d call ‘slim and trim’. Torque numbers aside, the 3.0 TDI falls short. So, two down now, one to go.
Our Final Answer
That leaves the 4.2 TDI V-8 as the obvious choice. Making only 22 percent less power than the current gasoline powered 4.2-liter found in the R8, it would produce a whopping 77 percent more torque! That’s 77 percent more force throwing you back into the seat when you hit the throttle, and maybe even 77 percent more fun. In the gasoline R8, the 317 lb-ft of peak torque hit high at 4500 rpm. In contrast, a 4.2 TDI V-8 R8 would make 561 lb-ft starting at 1800 rpm all the way to 2500 rpm. Now that’s what we call low-end grunt.
The 4.2 TDI propels the Audi Q7 from 0-to-62 mph in a claimed 6.4 seconds—and that’s an SUV. Factor in better gearing, less weight, and more grip and you start to get a feel for what the R8 4.2 TDI would be capable of. In addition, the diesel engine weighs less than 600 pounds, which isn’t too bad for a car on a diet.
Oh, and we can’t forget about the gas mileage. According to our estimates using the Q7 as our guidepost, the EPA fuel economy of an R8 4.2 TDI would jump from 14 mpg to 17 mpg—a 22 percent increase. Whether you use those extra 3 mpg for a few more sessions at your local track or avoid a stop en route to the country club, the choice is yours. As for getting the golf clubs in the car, you’re on your own.
So that’s our story and we’re sticking to it, at least for now. We are comforted knowing that, in the interim, we should see a Lamborghini Gallardo sourced V-10 in the - ONLY REGISTERED AND ACTIVATED USERS CAN SEE ALL LINKS - CLICK HERE TO REGISTER on our side of the pond. So, we figure we’re gonna be winners either way.

- ONLY REGISTERED AND ACTIVATED USERS CAN SEE ALL LINKS - CLICK HERE TO REGISTER

Thanks for the info Bartek. I have already mentioned the article in the previous page:

http://www.germancarzone.com/192642-post18.html

I'm not sure what the point of a diesel powered supercar is, is it to save fuel?

Because people who have enough money to afford an R8, well moneys not a problem, so they aren't going to care about fuel consumption. About the noise factor, I seem to remember hearing that the R10 which competed in Le Mans, was very quiet!

It's more about getting into the record books, for fame and recognition, that Audi has built the world's first diesel supercar.

I guess I'm going to have to dig deep for this one if it does end up coming true. Any estimates on the sticker?

Interesting. I doubt it will be very 'fuel efficient'. Compared to its petrol alternative yes a little bit but not much. I like the idea though, it will feel different from a petrol powered supercar. And diesels don't really sound that bad anymore in my opinion. OK when they are idle, it isnt the nicest engine sound in the world, but when they are revving hard, I actually think big diesel engines sound really good. They sound really powerful and almost spaceship like haha.