rsilvers129

The Ultra should handle the aquaplaning using ESC by comparing steering wheel angle with car yaw and modulating left and right brakes to correct car angle.

rsilvers129

I think sport mode locks it on. But it won’t be exactly like a center diff as the split is not the same. Torsen is RWD bias.

stanj

According to Audi it takes 80-100ms to engage rear drive. At normal speed that's way too slow to engage for the example I have given (the rear wheels will hit the water by the time it engages). Yes, it will do brakes etc just like any ESP did 20 years ago, but that's the same my FWD Mercedes would do, too.

Dan in St. Louis

In my Allroad it is "Drive Select > Offroad." Look under "Drive Select" in your Owners Manual.

rsilvers129

I was hell-bent on getting a manual, and not having a center-diff did play a role in me giving up on that. So now Audi will say that manual didn't sell well when they offered it in the A4 and use that as a reason to get rid of it next year.

adg44

There is absolutely no difference behind the wheel between a torsen system or the ultra system. To pass up the manual because if the new quattro is just silly. The car constantly reads the road and knows in advance if it needs to have quattro engaged. It looks at steering angle, throttle, how you have been driving since the ignition cycle, and what drive select mode you are in.

In the A4 you cannot lock the system like in the allroad or Q5.

rsilvers129

Probably true but no one has compared them yet with public results.

ropuff

So would it be incorrect to state that Quattro Ultra is basically a FWD-biased system, as opposed to the RWD-biased non-Ultra? Whether one could tell the difference unless driven at the limits of the car's capabilities is probably what really matters. But I wonder how many other potential owners would be turned off by the technical distinction.

Whether I'd notice it or not, I'm glad (as a DSG owner) that mine is not Ultra. The RWD-bias appeals to my sub-conscience. As with other types of products, psychology plays a huge part in purchasing decisions. All those years of reading about how RWD is superior for driving dynamics and experiencing firsthand the difference (especially when it comes to torque steer) between FWD and RWD cars. I hope Audi has engineered Ultra to be truly seamless in the sense that a difference really cannot be detected.

rsilvers129

Ultra is for sure FWD-based. It can't ever put more than 50% of torque to the rear (unless you count just via weight transfer), so it is never rear-bias.

Real quattro in A4 does 40/60 all the time, with some variation by using the ESC program.

I would probably never drive on the street in a way where I could detect a difference, if there is even a detectable difference at all. However, I am not sure that is the point. Lots of people buy lots of cars for engineering choices that they will never be able to exploit. Who buys a Stingray and will corner at 1.2 Gs on a highway offramp?

NorthwestB9

From everything I've read about Quattro with Ultra, nobody can tell the difference between the two. The Ultra system basically disengages the rear wheels when it doesn't matter whether you're driving FWD or RWD, such as cruising down the highway at a steady speed, which is probably a very large part of everyone's driving time. You could take a non-Quattro RWD and FWD in those circumstances and not be able to tell the difference in that type of driving condition. When you really need it, such as if you're hooning around or taking tight turns, or going through pools of water, both forms of Quattro will be throwing power to whichever wheel(s) needs it most. As you said, if you shy away from Quattro with Ultra, that's going to be purely from a psychological reason. I'm going to guess Audi put it only on A4 manuals (of all A4's) because that's the smallest pool of drivers, most of them who are enthusiasts, as a test. If Quattro with Ultra doesn't dry up manual sales, they'll spread it to all Audi cars eventually. By not drying up manual sales, that would mean the QwU system passed the test as to whether enthusiasts could tell the difference.

I'll compare QwU with the various engines that shut off pistons when they aren't needed, such as in the A3-RS3 or the A8. You get to save gas, and it shuts down a good part of the engine's power when it's not needed. Nobody seems to object to that, so why the objection to QwU?