Sebring 12 Hours: The amazing Audi R15 up close and uncovered ...

[Wouter Melissen]

Dear Ultimatecarpage.com visitor,

Saturday, 10:30 am local time, this year's edition of the legendary Sebring 12 Hours will kick off. One of the most talked of cars in the race is the brand new Audi R15 TDI. It represents a complete redesign compared to the three time Le Mans and two time Sebring winning R10. What remained was the TDI diesel technology but both the chassis and engine have been developed from scratch. The German engineers focused on creating a better balanced racing car, which has resulted in some very interesting solutions. Greatly contributing to the improved weight balanced is the V10 engine, which is shorter than the R10's V12 but still displaces 5.5 litre. No doubt the most striking feature of the new Audi racer is the aerodynamics package. Where most other manufacturers use sharp, clean lines, the R15 features a blunt nose and numerous subtle aerodynamics devices. What also is very obvious is the exceptionally low height of the car. From any angle, the R15 is an absolutely unique racing car.
The build up to the race has been ongoing since Monday and the new Audi has been among the top runners in every session. While it was pipped in qualifying, the R15 remains our favourite for the race win on Saturday. Providing a unique insight into this high-tech machine, we have compiled an exclusive 18-shot gallery, including a revealing look at the new engine.
Our full report of the race will be published early next week. For those of you in the United States, Speed TV will air 10 hours of the 12 Hour race live, so dial in before 10:30 am Eastern time.

2009 Audi R15 TDI - Images, Specifications and Information

Regards,
Wouter Melissen

[cmcpokey]

excellent shots wouter. best ive seen anywhere.

[RacingManiac]

Do you have more shots of front mechanical bits from other angles? Whats your impression of ALMS thus far?

[Kitdy]

Love the shots - especially the rapid update of them. A good chunk of quality shots the like outside press shots I can't recall seeing yet.

Looking forward to a nice big race report and slideshow after the race!

[henk4]

According to the specs, and therefore Audi, the engine produces only 600 BHP. The R10 was rumoured to be over 700, the new restrictor rules are supposedly reducing power by 10%. So what's the real power output of this one? 650? (a figure also obtainable from the Judd engine)

[togos452]

Thanks for the update on Audi's new le mans prototype.

[RacingManiac]

According to the specs, and therefore Audi, the engine produces only 600 BHP. The R10 was rumoured to be over 700, the new restrictor rules are supposedly reducing power by 10%. So what's the real power output of this one? 650? (a figure also obtainable from the Judd engine)

I had a thought about that. They are definitely making more power than they are quoting, but one of the interview/article I've read(I think it was either SPEEDTV or Autosport), they mentioned the challenge for the new car on the engineside was to produce a motor that is smaller and lighter than the old engine, and the updated restrictor rule(to limit the power advantage for diesel) helps them to do that. So they are probably overall designing the engine to be less powerful, therefore lowering the envelope of engine's performance to get size and weight reduction. Remembering when R10 just came out, the engine guy mentioned that for the amount of crank main bearing stresses, the only way to get that under control for the given performance envelope(I guess based on old restrictor rule) was to go with a 12 cylinder(not surprisingly, Peugeot arrived at the same conclusion). With less power, perhaps that stress is low enough to go with less cylinder. Remember that both Peugoet and Audi are all aluminum race motor, as opposed to the Touraeg-V10 based engine from that previous diesel attempt...

[Kitdy]

Remember that both Peugoet and Audi are all aluminum race motor, as opposed to the Touraeg-V10 based engine from that previous diesel attempt...

Who's attempt was that?

[henk4]

I had a thought about that. They are definitely making more power than they are quoting, but one of the interview/article I've read(I think it was either SPEEDTV or Autosport), they mentioned the challenge for the new car on the engineside was to produce a motor that is smaller and lighter than the old engine, and the updated restrictor rule(to limit the power advantage for diesel) helps them to do that. So they are probably overall designing the engine to be less powerful, therefore lowering the envelope of engine's performance to get size and weight reduction. Remembering when R10 just came out, the engine guy mentioned that for the amount of crank main bearing stresses, the only way to get that under control for the given performance envelope(I guess based on old restrictor rule) was to go with a 12 cylinder(not surprisingly, Peugeot arrived at the same conclusion). With less power, perhaps that stress is low enough to go with less cylinder. Remember that both Peugoet and Audi are all aluminum race motor, as opposed to the Touraeg-V10 based engine from that previous diesel attempt...

By what would be the advantages of a 600 BHP diesel over a 650 BHP Judd engine, also given the fact that the tank size in the diesel is 10% smaller.

[Wouter Melissen]

By what would be the advantages of a 600 BHP diesel over a 650 BHP Judd engine, also given the fact that the tank size in the diesel is 10% smaller.

The 500 Nm of torque perhaps? Judging from the top-speed captures Sam has been doing, the cars could be quite equal on power.

[henk4]

The 500 Nm of torque perhaps? Judging from the top-speed captures Sam has been doing, the cars could be quite equal on power.

which would give the Audi certainly more than 625 BHP....

[RacingManiac]

Torque...turbo diesel still makes a lot more torque than a normally aspirated Judd. It also works at a much less stress state with the rpm which should be gentler on most rotating components. The V10 is still quoted over 1000nm of torque, which is ~50% more torque than the Judd, at obviously a lot lower rpm. I am also sure that there are alot more flexibility in how you can adjust the engine during the race, for fuel economy or all out performance, considering you can change fuel map, boost pressure and perhaps turbo vane geometry map....

[LeonOfTheDead]

Torque...turbo diesel still makes a lot more torque than a normally aspirated Judd. It also works at a much less stress state with the rpm which should be gentler on most rotating components.

about that, I would say the stress could be still relevant due to thicker components in a diesel engine, therefore higher masses even for rotating components. still it's the rotating speed the main issue, and I doubt the mass is so much higher to balance the effect.
the Audi engine should be heavier than the Judd to equal the safety due to the higher stress generated by the diesel combustion process, so even considering an equal stress but an higher weight the torque is likely going to be give the Audi a better overall performance, regardless of 20 hp gap in power, if that's the case.

[Kitdy]

Leon, should Audi switching from a 5.5L V12 to a 5.5L V10 give the engine even more torque due to a presumably bigger bore? I'd imagine peak power may suffer a bit but torque should be up right? Speaking in rough terms of course.

[henk4]

Torque...turbo diesel still makes a lot more torque than a normally aspirated Judd. It also works at a much less stress state with the rpm which should be gentler on most rotating components.

Hm...all the advantages that I am trying to sell in my never ending discussions about diesel engines in normal road cars...
Obviously a suitable gearbox cannot compensate the relative absence of torque in a petrol engine...