FBA

Both my Macan and TTS have the button showing PDCC. Did Porsche make a mistake on the label?

NVRANUF

Sure... if my words brought you to those conclusions, then it must be true.

ace37

Quite a few threads have concluded that the PDCC on the button is marketing in action and it is still only the PASM setting that changes. Haven't seen anything official though.

First example thread from a google search: https://rennlist.com/forums/991/864109-pdcc-button-vs-shock-only-icon.html

squid42

As others have tried to explain, just because there is a "PDCC" label printed on a button does not mean you directly control it. That is still the PASM button and PDCC functionality change is rolled into PASM modes. You cannot control them separately and you cannot get any information about what it does and when it engages (maybe something is broadcast on the CAM bus or another bus we can get at in the OBD2 port).

I don't have PDCC a/b experience. In the BMW world I would not buy a 5/6/7 without their active-roll system (which works a bit differently). Huge difference. I dislike undocumented software switches, though. I can easily see myself zooming around in Cambridge wanting the suspension soft but body roll at a minimum as I dodge all the obstacles flying into my path left and right as if I am in a video game. Do I even know whether I can get that? Nope.

I am not aware of anybody who tried to separate out PASM and PDCC effects by pulling fuses or plugs, and chances are that the entire suspension goes into failsafe when one component goes possum.

MaxLTV

The button has a picture of a shock absorber on it, right? It's basically turning on/off sports mode for shocks and PDCC. It's not turning PDCC on/off, but rather turning this button on makes PDCC emulate stiff roll bars, and with it off, PDCC is more dynamic, fully relaxing roll bars when not cornering aggressively. Here is a copy from the manual:

Damper firmness activated
PDCC (if equipped) response is increased
NOTE: May be disengaged after activated by the Sport or Sports Plus buttons

MaxLTV

FWIW, I do not have a Turbo, just planning to order one. I test drove Turbo (no PDCC) and Turbo S (with PDCC) at Porsche Center in Atlanta. Could feel the difference in handling when cornering hard and especially when transitioning (like S curves). I could NOT feel the difference in compliance, but the roads were perfect there - it's a new facility.

On Cayenne, in contrast, both cornering at the limit and comfort in normal driving have an extremely noticeable difference for PDCC vs. no PDCC. I think the higher the center of gravity and the softer the suspension, the more benefit PDCC would offer.

mark12345

Good grief. I talked to my friend that is a tech at my local Porsche dealership for over 10 years.

He said this, "Yes, definitely there is a noticeable difference when PDCC is on/off specifically for lateral movement. Is it necessary for a TT/TTS, especially if you already have PASM/SPASM? No! However, adding PDCC will help further to minimize lateral body movement by an active anti-roll system. It does not lower or stiffen the ride, it is there to control lateral movement. If you are not driving aggressive around town, you may not notice it as much if you were driving it on track."

worf928

This I can agree with, except perhaps the 'irony' part: it's just human nature to rationalize. And thus why it's important to understand an observer's true context and reasoning and to fight human nature when it's counter-productive.

I would have to nod to a comment, that perhaps, those that researched PDDC before back-to-back testing might have suffered from observer bias: My expectations may have affected my observations and conclusion due to my research. But, at this point, I'm a believer in PDDC for crappy-road-DD use and that's my story and I'm sticking to it. I notice a difference when I drive my wife's 981S on the same roads I drive my 991TT. (But, that's still a target for observer bias complaints.)

No need to apologize. I was feeling pretty grumpy and regretted my post soon after hitting send. But, hey, that's what the Internet's for...

Yup. My Turbo started out as a C4S. Once I got into 'Turbo Territory' I quit worrying about 'value' and just worried about if an option would contribute to my enjoyment (or, in the case of lack-of-PDDC detract from my enjoyment.)

No mistake ...

... in my opinion, having either contributed-to, or lurked-on, the above thread and having read the available material pertaining to PDDC: It's all about Marketing the label on the button.

If you consider how suspensions in general work, and specifically how PDDC works, this is the expected observation. PDDC provides 'stiff' anti-roll bars when cornering and 'soft' anti-roll bars when driving straight (more-or-less) over bumps and irregularities in the road.

If you corner hard and fast on rough pavement and then go more-slowly over the same patch of corner then the difference is obvious: you'll skip over the pavement when cornering fast, but, when cornering more-sedately stick to the road. And yes, I get to do this test 2.5 times per week.

Nail? Meet coffin.

fleadh

I asked one of the engineers in Germany that developed the system and one of the works drivers who helped test it: On the 991.2 TTS when the PDCC console button is deactivated (light is off), both the PASM and PDCC is put into a "normal/comfort mode" which softens the compression damping of the shocks, adds some rebound damping, and reduces both the front and rear roll stiffness (PDCC). The PDCC is always active, it's mode is altered.

Conversely, when the PDCC console button is activated (light on), the dampers are stiffened by a large amount and the PDCC is put into "performance mode" which severely controls chassis roll depending on other factors (if it thinks you're turning or going over bumps, etc).

I haven't driven a 991.2 TTS with out the PDCC option, but I'd be surprised if it's baseline rollbar settings aren't a little stiffer than the PDCC enabled car (with the PDCC button turned off) to make up for the inability to dynamically control them. Would be interesting to drive them side by side.

As it stands, I still like my 991.2 TTS with the PDCC button turned off for all driving -- cruising and spirited.

-mike