Hi Guys, A friend of mine is getting a '14 GTR - per him the mean time between shifts is 0.15sec for GTR... we searched but couldn't find same info for 991 4S (or S). Any ideas what's this time for PDK in 991?? Cheers!

 

great question, not sure i have the definite answer, but on the main porsche website:

http://www.porsche.com/usa/models/91.../detail/drive/


"The flow of power from the engine is transmitted through one half gearbox and one clutch at a time, while the next gear is preselected in the second half gearbox. During a gear change, therefore, one clutch simply opens and the other closes at the same time, enabling gear changes to take place within milliseconds."

presumably, porsche means just a few milliseconds (like say 10), so that takes it down to 0.010 seconds or less per gear change, almost essentially instantaneous to human perception as those who have driven it have accurately reported. to put that in perspective, a blink of the eye takes about 300msec. wow!

 

The time obviously applies for the actual shift once everything is setup.
If not, it takes a lot longer.
Just drive the PDK in manual (limo or sport mode) - there can be quite a noticeable delay from pulling the paddle to the change taking place.
The time seems less in Sport+ mode but it certainly is not instant.

It's not a biggie though as you get to compensate for it and simply pull the paddle a touch early.

To be perfectly fair, even the delay in limo mode is less than I can do with a proper manual transmission, even if I try very hard.

Rainier

 

I had an M3 with SMG. BMW claimed it shifted in .08 seconds, but in reality, the shifts were a lot slower than any DCT/PDK I have driven, so those numbers mean nothing.

 

After the command is made, the shift might be less than 50-75 ms, but the command probably takes the most time. Ranier describes the benefit best, however, in that with PDK you can compensate for the command latency, with a manual you can't do that as well- especially in the downshift! The difference is shown in the 0-60 times between the MT and the PDK.

ChuckJ

 

I've had 3 GTRs and I believe PDK shifts faster than the GTR transmission. PDK is an amazing technology.

 

Rainier, I don't have a PDK, but did have a Single clutch paddle shift transmission on my BMW X5M. I found that in both, my test drives of the PDK and my X5M, if you keep your foot deep in the throttle, and you don't let up like you do on a manual transmission shift, shifts are lightning quick, especially in Sport Plus.

 

+1.

By a few milliseconds. As stated, the latency differs (depending on mode). Once this timing is learned, the shift points are mentally adjusted/compensated. Let's say I'm accelerating and want to shift at 7000RPM's. If I know at 'x' gear under 'y' throttle on 'z' slope, I increase RPM's at 'xyz' rate. While under throttle, I shift when approaching 6700 RPM's (in a certain mode), the gear change itself is only a few milliseconds, but the shift may occur around 6950 or so.

This may make a .1-2 sec difference in an ET on a drag strip, or .3-4 secs around any given lap.

If one is looking for consistency, better to put in appropriate mode (most all dual clutch setups have multiple modes), and let the computer choose the best gear. Then you can set your watch according to your lap times (probably while driving).

 

I owned a '13 M3 DCT.....the shifts in "M" mode - manual, for lack of a better
word, slammed hard. Quite impressive when you don't know otherwise.

My PDK is very different. The shifts are seamless & smooth, but quick.
In the auto mode w/ sport or sport plus, it seems to know what gear to be in - up or down, if you choose to let it think on it's own.

One other big difference is that at slow speeds the PDK is not jerky. W/the BMW DCT I had to be careful when crawling along in traffic - abrupt starts
& stops kept you on you toes.

 

And you got rid of it already because of the poor DCT?

I thought about the M3 but never investigated it. How different cost wise compared to an equally equipped base 911 (engine notwithstanding)?

 

I didn't say I got rid of it because of the DCT....Good car, just wasn't the right car for me. German rice magnet.

Cost wise going to an "S"..... MSRP to MSRP $42K (M3 was a loaded Lime Rock DCT)

 

Heck yea it is!

 

I recall reading that the PDK shifts where something in the order of 0.04 seconds.

That would be 40 milliseconds if my math skills are still correct.

 

ummm...REALLY...REALLY FAST! I was blown away at how fast the new 991 with PDK shifted compared to my Panamera and Turbo Cayenne.

 

Wow, that was one serious special order, but I understand your point. Could I ask how much was that car, and how much hit did you take?