If you mash the gas pedal in manual shift mode and do not release at redline, will the PDK transmission automatically upshift at redline (like a Tiptronic) or will the PDK bounce off of the rev limiter and not automatically upshift?

If the PDK will automatically upshift at redline, is this the fastest means of acceleration, or does the car accelerate faster if the driver shifts before redline?

If the PDK will not automatically upshift at redline in manual mode, can faster acceleration be achieved by starting in auto mode and allowing the PDK to automatically upshift at redline?

Thanks,

Craig

 

I think I have found the answer in the Owners Manual ("OM"):

On page 150, under the heading "kickdown," the OM states that "the kickdown function is active in selector level positions D and M . . . . upward shifts occur at the highest possible engine speeds." This appears to indicate that, when kickdown is activated (the accelerator pedal is depressed beyond the full throttle position), upshifting will occur automatically "at the highest possible engine speed" and this kickdown function is available in both manual and auto modes.

On page 151, the OM states that "there is no automatic upshift at the upper engine speed limit in selector level position M." However, in the very next sentence, the OM states: "Upshift supression can be cancelled by kickdown operation. If, for example, the engine speed limit is reached during overtaking and the automatic upshift does not occur, the transmission in this case shifts up as a result of kickdown operation."

Not the clearest description, but the OM appears to state that the PDK transmission will upshift automaticallly at redline in manual mode, but only in kickdown. Do you read the above-quoted provisions the same way?

Assuming I have read this correctly, the question remains is this the fastest method of acceleration?

Craig

 

It will shift at redline.

That's a bit more difficult to answer. The car's peak power and torque band drops off before redline. So, when you are allowing the car to redline before shifting, you're outside the peak performance band.
On the other hand, acceleration is so aggressive for the first 100 to 120 miles an hour that you would have already rocketed through the gears in auto mode (whether the shifter is in manual or not) that you really have hardly any reaction time at all.
So, in theory, you could probably achieve a minuscule better time by manual shifting while staying in the ideal power/torque band, but, in practice, it will be very very hard to do.

If you are in WOT, shifts will take place automatically (unless you over ride by manual shifts) whether the gear lever is in manual or drive.
In both cases, it will go to redline in WOT before shifting.
I have not seen any evidence, despite many experimental runs, to suggest a repeatable performance difference in whether you leave the lever in D or in M.
In some runs, I got better results in D, and in other, M was better.
We are talking about infinitesimally small differences in times.
They could be due to IATs, tire temperature, traction off the line, etc...

The good news is, whether you are in D or M or you're shifting manually, it is devastatingly fast!

Hope this helps.

 

Interesting topic as I was just thinking of this the other day.
So if you have the launch control activated in the sport plus mode, does it make sense to just leave the tranny in D mode for the best acceleration times?

 

Doesn't really make much of a difference in my experience.
You could have it in either manual or drive.

 

Bingo !!

This is exactly what I would describe with my 997S PDK. It will upshift but if it isn't in "kickdown" mode it will simply cut off . It won't over rev when it cuts off but until I shift it to the next gear it's in a suspended state .
In "kickdown" it WILL shift automatically .

The problem these guys faced when they tested the car at the track is that it would hit the cutoff so they opted for sport plus automatic mode (on the track).
http://www.autoblog.com/2008/10/20/f...ra-s-with-pdk/
Quoted from article --
On the road circuit, the Carrera S with PDK was a whole different animal. While the PDK selector can be moved to "manual" mode, we found ourselves bouncing off redline/fuel cutoff coming out of the corners (PDK will not select the next gear in manual mode). We instead chose to leave PDK in Drive, the "Sport Plus" button activated, and the PASM in sport mode.