Our day at Cadwell ...

[HYFR]

MRC disconnect the diff when dyno'ing the R8

[bam_bam]

MRC disconnect the diff when dyno'ing the R8

Inter-arresting... why for man?

[HYFR]

think they said the diff oil gets too hot ?

[W8PMC]

How is it different?

erm, B7 was up to 60:40

R8 is up to 90:10 IIRC

and after owning both, they drove VERY VERY VERY different, as in night and day, and this was apparent on my very first drive home in the R8

dude, lighten up ... you're in danger of coming across as abit of a GT-R fanboy

That could never happen

Obviously just had very different experiences to you Not doubting they all drive different as common sense dictates that, however i was purely relating to traction & that i found very similar in the B7 RS4 & V8 R8 (didn't drive a V10 on track so can't really compare).

I found the V8 & V10 very different in the traction dept. (ignoring the obvious power differences) so had assumed the Quattro on the V10 was different to the V8 & thus the V8 similar to it's donor RS4. Without trawling for details on the technology, it appears the V10 has a maximum 15/85 split & it would appear this is the same in the V8. I'd be interested to know the mechanical difference if it exists between the R8 & RS4 Quattro set-ups.

As for the GT-R, i am indeed a fan, however had many more Audi's (including RS's) before the GT-R & am in an Audi currently, but i was interested to hear how it was felt the R8 V10 was alot quicker in the twisties when on paper it clearly isn't.

http://www.fastestlaps.com/cars/audi_r8_v10_52_fsi.html
http://www.fastestlaps.com/cars/nissan_gt-r_2011.html

My guess is brakes were the key difference, given the R8 was clad in Ceramics, but as i wasn't there (this time) i can only guess. Not keen on quoting videos, but as per Autocar in the test below "carries more speed into & out of the corners" However he does state with better brakes & the flappy paddle box, the R8 would be closer.

Saying all that, depending on how the new 991 Turbo stacks up, an R8 V10 could well be my prefered ride come next change.

http://www.youtube.com/watch?v=4OTUHgTAMMU

[bam_bam]

15/85 torque split by default (NOT maximum) then when rear traction is lost a maximum of 30% is sent north to the front leaving 70% at the tail. It doesn't appear to be Torsen quattro, so therefore suggesting the B7 RS drivetrain isn't a donor or even comparable, at all. Getting a similar driving experience from FAWD 40/60 vs MAWD 15/85 seems a bit odd. 'Mechanically' the R8 is a viscous coupling up the front, it might be worth digging around in the Lambo Gay-Hard-o specs for a better answer, it's difficult to find anything on the R8 drivetrain. Not flaming, just very interested in the answer.
Maybe someone has a quattro book on the R8, what about you lads that did the R8 factory tour?

[W8PMC]

Will try to get better data tomorrow, but found this regarding the B7 RS4 & this states that it was fitted with the a 'New' generation Quattro with Torsen Centre Diff. It also says 'under normal road conditions transmits 40/60'

Getting all this power on to the road was of course a significant challenge. Audi’s answer is – of course – its quattro permanent four-wheel drive system. A quarter of a century’s experience and market leadership in the four-wheel drive car segment represent genuine benefits for Audi’s customers. The RS 4 features a new generation of quattro drive with asymmetric/dynamic torque distribution.

A Torsen centre differential distributes the power to the front and rear wheels as required, thereby ensuring optimum traction. In variable road conditions the power can be immediately diverted in full to the front or rear depending on the torque. The new distribution system, which under normal road conditions transmits 40 percent of the power to the front wheels and 60 percent to the rear, makes the Audi RS 4 an even more impressively dynamic drive. Alongside traction, controllability, stability, load reversal and transitioning, aspects of agility and steering have also been substantially enhanced, underscoring the highly sporty character of the car.

Also found this but not giving much more away as it mentions 'normal' & 'default'

quattro
Another focus of the B7 RS4 was on the introduction of the latest development of Audi's 'trademark' quattro permanent four-wheel drive system.[4][5] This utilised the 'third generation' asymmetric/dynamic[5] Torsen[4][5] T-3 'automatic torque biasing' (ATB) centre differential, featuring a 'default' 40:60 front-to-rear torque split under normal conditions. Audi stressed that this would result in a more neutral response in corners, and a more dynamic driving experience. Also, a more aggressive Torque Bias Ratio (TBR) was used, and set to 4:1, as opposed to 2:1 (and later variants 3:1 TBR) on standard A4.[citation needed] That means that one side of the differential can handle up to 80%, while the other side would have to only handle 20% of applied torque.

Front and rear axle differentials are conventional "open" types, with a final drive ratio of 4.111.[4]

Traction is assisted by way of Audi's "Electronic Differential Lock" (EDL),[4][5] which is a specific function of the Robert Bosch GmbH ESP 8.0 Electronic Stability Programme system. EDL monitors the rotational speeds of the left and right wheels across an individual axle, and if one wheel should rotate faster than the other (exceeding the pre-defined parameters), indicating loss of traction, or "wheel spin" on one wheel, the EDL applies the brakes to that individual spinning wheel,[4] and thus results in transferring torque across the open differential to the wheel on the other side deemed to have grip, hence traction. Also included in the ESP 8.0 is "Anti Slip Regulation" (ASR) - Audi's name for Traction Control System.[5]

The result of all these features is that under normal circumstances (driving straight on dry or even wet road surfaces) the car never loses traction, even when accelerating at full throttle in the first gear.

Just found this on the RS4, but i can't be sure if it relates to the B7 or the B8:

The latest version of quattro, found in the Audi RS 4 typically sends 60 percent of its power to the rear axle and 40 to the front – delivering a sporty driving experience. As road conditions demand a maximum of 80 percent can be sent to the rear axel and 60 percent to the front. All of which ensures complete stability and traction whatever the situation.

[bam_bam]

Just found this on the RS4, but i can't be sure if it relates to the B7 or the B8:

...80 percent can be sent to the rear axel and 60 percent to the front.

Not sure on the maths for that one.
4:1 is for the B7. The crown diff in the B8 can do all sorts of magic like 20/80 IIRC. In the not too distant future all RSesse will sadly run a version of Haldex, methinks.
I'm very interested in what the R8 platform drive-train is though.