Audi R8 quick change rear end-what was so special?

[chernaudi]

Anyone who's followed sportscar racing likely knows of Audi's quick change rear end on the R8, and that the ACO essentally banned it's use in races after the end of the 2003 ALMS season as a cost cutting measure and to level the playing field(only Cadillac had a similar device, and Reynard and Crawford used the god-awful Gemini QC box that was unreliable and took considerably longer than the Audis')

But I would like to know what, if anything, was so special about the R8's QCGB that so few were able to duplicate the concept-as far as I know, the gearbox was mounted to the bellhousing/engine block with four bolts and 6 quick release hoses(2 for the gearbox oil, 2 for the brake lines, and 2 for the air lines for the electro-pnumatic gear selector system).

If it's that simple(quick release hoses are used on the impact wrenches/air guns used for wheel changes, and on the suspension for the brake lines on the cars), why couldn't anyone else essentally do something similar? Or was the ACO/IMSA concerned about the cost of ancillary equiment(the hoists, for example, which I don't believe were too expensive all things considered)?

[DanJR1]

Nothing was too special about it. It was a simple well thoughout design, well implemented especially with the Joest team working it. Guess it was banned due to game-changing implications it had (i.e. gearboxes designed lighter for 12 hours use and all the costs involved)

[chernaudi]

It can't be that light when the R10 and R15 gearboxes are made out of forged aluminium(the R8's casing was magnisum) and are claimed to be ligher, and the Acura ARX-02 gearbox casing was forged aluminum, and it at least as light as the R8's-maybe too many privateers complained and didn't want to jerry-rig their own system together(you'd have though that Panoz would've on the LMP07-but getting the rear bodywork off that car was a several minute chore in itself-the only removable panel was that which covered the electronics at the rear of the car). And what of the acnilarry components to allow the change to occur in the garage in the first place-the lifts and hoist, and having to daisy-chain all that stuff?

And when one considers that Audi designed the R8's(and for that matter, the R10's and R15's) engine to last 30 hours between rebuilds aside from oil and spark plug changes(and other very minor maintance), one could assume that the gearbox internals should last as long before total rebuilds.

As I said, simple technology, so why did so few adapt(only Cadillac designed a similar rear end on their LMP02, and Bentley chose not to design their own QCB, instead going with what Peter Ellary described as a heavily modified BMW/XTrac unit from the LMR)?

[betablocker]

i think its the sheer professionalism in actually being able to do that.

sub 4 minute rear end change is increadably impressive, to have all the bits off the hoist in poisition and the other ready to go its increadible. and its not like it was a fluke i think they did it a few times, different years etc.

ive worked on sportscars where its taken longer than that to take the floor off!!

the r8 gearbox was never particularly strong for whatever reason. sportscar gearboxes built correctly will last 24hrs, and im sure joest dont half arse the rebuilds. wheather the engine characterisitcs created a situation which put it too close to the box limits i dont know.

but after they changed the rules though it became a lot stronger or they actually fixed the real weak areas

[broadrun96]

I think everyone hit it right on the head, nothing was special about the actual units, just in the application and use of racing knowledge. The team and engineers knew what could happen in the race and so built repairability into the construction of the base car. Not sure that it actually cost more, but it caught out the other constructors and only Cadillac had the desire to match Audi's effort. I'm surprised more teams haven't petitioned the ACO to allow them to build the cars to have this quick repair feature from the start, especially when the LMP1/LMP2 rules came out. If Porsche, Creation, Pescarolo, Radical, and later Acura were allowed to consider this from a blank sheet the cost increases would have been controlled and more cars could have been returned to competition. I'm sure the ACO would have had to add rules allowing only one rear end and one front sub-frame (if such design would be possible) per chassis and it must have the same settings as the one on the car, hard to observe and verify I know. Most teams, except Pugeot apparently seemed to take a long time at LM on the front, have all developed quick change body panels to allow both easy access/replacement and sometimes change downforce mid-race and nobodies upset about the costs involved there because it can help cars stay competitive in the race. Unless your driver is Jon Field and he has decided that through the grass at Mosport and Road America would be quicker, it was for a couple laps but the front clip has a bad habit of shaking when unbalanced.

[Félix]

I guess they were just banned because of cost considerations (how much for an extra gearbox you have to have lying around? 100K?) and for the spirit of the regulations: this has to be endurance racing, so switching mechanical components during a 24 is not a proof of endurance.

It's a little bit the same with the front and rear bodywork panels the works teams can change 5 times in a race or as soon as it starts racing... the prices quoted for R8 front cowling and engine cover were in the 30K+ range; most privateers show up to a race with 3 sets I guess and they're for emergency repairs, not for performance fine-tuning.

Also, I seem to remember William Hewland speaking about the Audi gearbox and abut how it was basically a fairly simple Formula Nippon design massaged and refined for endurance racing.

[chernaudi]

One problem with the assertion that the R8's gearbox wasn't well-built enough is that gearbox failure on the R8 were as rare if not rarer than most other machinery.

In the book Audi R8: Born to Win, Audi reveals that in 2000, the reason behind the gearbox changes wasn't gearbox related-Audi for some reason was busting ball joints in the rear suspension, so after contact, spins, and punctures, they were very leary about suspension failures, hence the rear end changes.

In 2001, electonics problems with the gearchange dictated the change of the gearboxes-Bentley had the same problems, but took much longer to fix-for Audi it took 5 minutes with the QCG, while it took Bentley 10-15 minutes to sort out the same electical grimlins, because they used a "traditional" gearbox.

After 2001, Audi only used the QCB only for accidents that involved massive suspension/rear end damage-Audi's biggest problems at LM in '02 were punctures and starter motor failures, and the quick change rear end wasn't particulary useful, as the starter was attached to the engine block.

And not to start a flame war, but as much as I admire the fact that one of Hewland's gearboxes did well at LM in 2000 in the Pescarolo Courage C52, their new LMP gearbox(used by Lister and Courage) were kinda junk, which is why Acura builds their own gearboxes(with XTrac internals) and why Lola designs their own gearbox casings(Lola still uses Hewland internals, don't they).

And I believe why Audi switched to XTrac on the R10 and R15 for gearbox internals is that VAG has some kind of contract with XTrac since the Toureg Rally Raid cars were first made.