Jack88

I can't say I've had exactly the same experience with the sport diff. I did note better rotation about a corner, but at speed cornering stability was unaffected. Maybe I didn't push the loaner hard enough for that to come to light but I didn't feel anything beyond mitigating some understeer as compared to my normal A8L. The S8 felt much the same as my car at speed around a corner, other than the amusement I got from watching the salesman in the passenger seat visibly clench, in terms of stability. Stability control, however, works very, very well on all models. It's been a very well behaved car for me, even in panic maneuvers. Fifth Gear did an episode on stability control I liked, at the risk of appearing too ADD, here it is. .

Mike911A8

Derf, I had recalled your previous advice re the sports differential and I asked the salesman if the test car had it; it did not. My test drive was a toe in the water with respect to a possible D4 move. I had not driven the 4.0t, so I wanted to get a feel for it. It does come on strong, and I wanted to see just how the oft reported throttle lag really felt; it wasn't too bad.

I really like my D3, so it would take something special to move me out of it. But I did ask the salesman to give me a call the next time a S8 comes in. That should check all the boxes: SWB, sports diff, and some more juice! Mike

derfA8L

Re: Rear Sports Diff + Dynamic Steering....My Experience:

Upon D4 launch, took a SWB launch demo (non-sport/non sports diff) to a well known "heart attack" corner for a test.

Corner description: Quarter mile down hill straight-away bottoming at a seemingly 90-degree elbow curve.

I took the downhill at about 30mph; entered the curve at same speed with some moderate acceleration into the corner. The car held the road, but barely, and with a lot of corrective steering needed to keep the car straight upon leaving the corner---and with me nearly wetting my pants. Discussed this experience with my ABS and he described his experience in Germany during the dealer D4 product launch event where he track drove numerous A8's---that is when he convinced me to add the rear sports differential to my LWB order. Several months later when the LWB D4's landed here I repeated the "heart attack" corner test with a LWB demo (again no sport package and no rear sport diff) resulting in the same unimpressive handling, but this time I went a wee bit slower---yes, call me chicken 🐓

After my new 2011 LWB D4 was delivered I repeated the same test at 30mph and the difference in handling---specifically cornering stability and control---was almost magical...the car's rear end never jiggled and remained firmly planted, where the two demo tests with non-sports diff felt as if the rear would break contact, as well as the car now remaining straight and true coming out of the curve with no corrective steering required. Happy camper I went with the rear sport diff+dynamic steering, since there are numerous sharp corners along my normal routes...As well as the occasional immediate deer avoidance maneuver.

Tire note: 1st test with SWB launch demo - 20" A/S configuration; 2nd test in LWB demo also with 20" A/S; my delivered 2011 LWB had 19" A/S which had the disadvantage of having a taller sidewall.

Jack88

My test road of choice feature a progressive left followed immediately by a tight chicane, complete with dips to unsettle the chassis. I can't push my car as hard as the sport equipped loaner through there, but maybe if I tried, I'd run into the hairy situation you describe. By the sound of it, you push harder than I do, Derf. D.C. area isn't conducive to harmless fun, the tickets would get to be a problem quickly, if the moronic residents didn't get to be the problem first.

derfA8L

The road(s) I'm describing are rural back roads I frequently ride on weekends. I'm certain that your car is perfectly capable 99.999999% of the time---my non-sport D3 LWB cars certainly were, including on back road fun twisties. There are some situations that the sports diff and dynamic steering are just invaluable IMO, even if used only once in an accident avoidance setting (I'm referring to my post from last year about its helping keep my car under control in a highway high-speed near miss). With all the great (and sometimes needless) tech that is being crammed into the A8, I just wish Audi would include this particular option combo as standard equipment...A matter of both safety and added performance, and, having experienced its safety benefit, IMO worth the added marginal expense in a $100K range automobile...Even if it's utility/usefulness never has the occasion to come into play or be overtly noticed by the driver.

Hopefully, no one here thinks that I'm disparaging their rides if they don't have the rear sports differential---I'm just a vocal advocate of this particular technology and equipment in the A8.

Mike911A8

Thanks for the info derf and jack. A lot of my driving is back roads which I enjoy taking with some speed, so I guess I'll wait and see what an S8 feels like when I get a chance. I like to power thru some turns and I think Quattro tends to stabilize thru turns with the correct power applied, so my next experiment will be to see if I can do that with a turbocharged engine as easily as with the NA V8. Mike

derfA8L

Not sure Quattro is intended to duplicate what a dedicated torque vectoring system is supposed to do; but any D4 S8 will have the dynamic steering and rear sports differential so you'll have the best of all handling worlds going: Quattro, sport tuned suspension, dynamic steering and sports differential. Have fun!