Glisse

IIRC, the head of M division, Frank van Meel (who was poached from quattro GmbH / Audi Sport where he was a senior engineer) said the new G30 M5 moved to Steptronic (I assume it is a ZF8HP-90, same as RS6/RS7 use) rather than DCT is that it works better with AWD and high torque at low rpm. Dual sequential transmissions are innately better suited to high power vs high torque engines (particularly high torque at low rpm) due to dynamic torque shock through the drive train. To build them strong enough to cope with static torque multiplication, it becomes impossible to make them smooth at low speed changes. Which offends journalists and "sensitive" customers. The other way to reduce the dynamic torque multiplier (which can be up to 10 times the static torque) is to reduce shift speed, and then they offer no performance advantage over an automatic transmission.

So I agree with you. I just miss the direct connection, the snick if you like. No matter how quick the changes may be, and the ZF8HP is very good, a torque converter always feels a bit "rubbery" to me between changes.

Glisse

Absolutely, although for me the achilles heel of the DL501 was a two gear downshift (so changing down on the same shaft, particularly if the system was expecting an upshift) from a cruise, which is not that quick. The ZF8HP is better on downshifts in that situation.

But Auto, Comfort, Economy (which NA don't get IIRC) MMI drive modes, and D transmission modes are designed for efficiency, not performance.

In the link below, Automann is driving the RS4 in manual mode. And yes, that is how to extract the performance.

The 2.9 twin turbo is not quite as responsive in low down torque as the 3.0's twin scroll. The S4/S5 uses a ZF8HP-55, I don't know which version the RS4/RS5 are using, probably ZF8HP-75. Whichever, he is bouncing off the limiter half the time, no redline change up in manual mode. Excellent. And to head off comments, Automann's driving gloves are a signature device, as he never shows his face. He drives all the high performance German cars, has owned owned Audi for a number of years, although his current fleet is M2, G30 M550i, Mercedes-AMG C63s. He is remarkably unbiased when it comes to marques, which is why I find him useful as a datapoint. More so than most print media sources, which seem to have gone downhill:

N8!

I dig that guy's gloves. When he puts them on you know he's 100% serious about driving.

NoMoreBMWs

But if you drove like that just about anywhere in North America your car would be crushed into a rather small cube. Hence I wonder about the relevance of the RS5 here (except to bragging rights).

visualguy

It's irrelevant in most places in the world, but some people will still buy it even in places where its enhanced capabilities can't be used... I would spend the extra money on more luxury, comfort, and safety that I can enjoy rather than more performance and handling that I can't, but people are different in what appeals to them.

Stankia

If the Chiron's dual clutch transmission can handle 1,180lb-ft of torque then so could one in the Audi S5 with its measly 369 torques. The problem is not a technical limitation but cost and driver comfort. I wish Audi would straight up admit it.

ArvX147

I dont agree that you can compare the use of the DL501 in the S6/S7 and PDK/Porsche to audi.

Worldwide the numbers sold per year of a B9 S cars have to be over 10x the porsche and new A8 models that feature this trans, combine this with the much higher pricetag of the porsche and you see the risk based decision point to drop the DL 501 in these cars. Price matters, it means they can afford to more tightly QC the transmissions at the factory, and that they can certainly afford to take the hit on the small number of trans that have a problem.

Transition to the B9 where the margins are slimmer and less can be done to control the issues, you've now turned a small engineering flaw into a major problem, as I stated before.

As for the S6/S7 those cars retained the DL501 mostly because they were released shortly after the B8, and they didnt want to change the trans mid cycle. The RS7 got the ZF8 though

Glisse made some great informative points re:trans revisions and the history, but failed to consider price point of the vehicle and production numbers in his assessment.

stan23

you realize there is more than 1 dual clutch transmission, right? That's like saying a 4 cylinder motors should and could make the exact same amount of power.

machz

I don't think they are trying to deny it. I'm sure they are confident with enough money they could build one but it would push the price of the car too high. In this price range they went with what the engineers thought was best between comfort , performance, price and reliability.

NoMoreBMWs

I'm just speculating here, but the ZF 8 comes with a generic set of integration interfaces which likely cuts development cost and time, but could lead to less well-honed specifics in the integration - such as throttle response. Increasingly it seems to me that even M-Bs, BMWs and Audis are built from third party menus.