doctp12

What is the difference between the PDK-S in the 991 GT3 and the PDK In 991 other than the GT3?

Stronger gear box?
Faster shifting? Ferrari's 430 has a single clutch system at about 150 milliseconds.

Can an experienced driver feel the difference between the PDK-S and the PDK?

bronson7

I've always had MT Pcars, so I can't comment on the comparison between PDK-S vs PDK. What I can say is the PDK-S shifts faster than the Fcar....articles have reported, PDK-S shifts in less than 100 milliseconds.

PC Valkyrie

1) Mechanical changes: lighter gears and shorter gear ratios (maximum speed attained in 7th gear)
2) Faster shift times: "less than 100 milliseconds"
3) Superior software: when in automatic mode, PDK-S has superior shift maps that are better tailored to track use (it just "knows" what gear it should be in when braking before a corner, and will hold gears appropriately longer when cornering and accelerating).
4) Superior shifting "feel" with shorter throws when pulling the paddles. Also, when using the centre stick to shift, upshifts occur when pulling the stick back, and downshifts occur when pushing the stick forward (reverse of the normal PDK).
5) Paddle neutral function: ability to put the car in neutral instantly when pulling both paddles simultaneously and then reengaging gears instantly by letting go of the paddles.
6) No forward "creep" when not pressing the accelerator when in Drive

Mike in CA

Lots of differences that are readily apparent to any driver. Search for PDK-S and there is a ton of info and feedback on this forum. This should get you started....

Compared with the Porsche Doppelkupplung (PDK) used on the current Porsche models,
the main development objectives for the PDK transmission on the new 911 GT3
were as follows:
• Improving performance
• Reducing complexity
• Motor sports-oriented operating strategy
• More intensive interaction between vehicle and driver
• Enhancing emotionality

These objectives were achieved by a complete overhaul of the gearshift functions
and strategies as well as the transmission ratios and controls.

Technical data
Transmission weight (wet, ready for installation) . . . . . . . . . . . .260 lbs. (117.5 kg)
Transmission weight (dry) . . . . . . . . . . . . . . . . . . . . . . . . . . . .243 lbs. (110.2 kg)
1st gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 3.750
2nd gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 2.381
3rd gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 1.720
4th gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 1.344
5th gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 1.114
6th gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 0.957
7th gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 0.844
Reverse gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 3.417
Final-drive ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 3.973
Basic transmission
The Porsche Doppelkupplung (PDK) was modified significantly based on the current
911 Carrera models in order to adapt it to the performance-oriented objectives of the
new 911 GT3. These modifications include, shorter transmission ratios, shift paddles
with a shorter shift throw and a more precise one-touch function, an improved sporty
shift feeling with performance-oriented shift programs and significantly shorter shift
and response times. In addition, the shifting direction for manual gear changes on the
selector lever in the center console has been adapted to suit the requirements for
professional motor sports. As a result, upshifts “+” take place backwards and downshifts
“–” take place forwards on the new 911 GT3.
The basic functional and mechanical features of the Porsche Doppelkupplung (PDK)
are the same as the tried-and-tested Porsche Doppelkupplung (PDK) used in the current
911 generation (991). Improvements on the new 911 GT3 include the oil supply
and lubrication of the individual gear wheel sets (especially 5th and 7th gear) to
ensure a reliable oil supply even when driving on race circuits while taking into
account the much higher lateral acceleration potential of the new 911 GT3. The use
of lighter gear wheels and gear wheel sets has also resulted in a weight saving of
approximately 4 lbs. ( 1.8 kg).
The final-drive ratio and the complete gear wheel set with all gear ratios from 1st to
7th gear are new for the 911 GT3. To improve driving performance, the new 911
GT3 therefore has gear ratios that are much shorter than on the 911 Carrera models.
These can be up to 9% shorter than on the 911 Carrera S, depending on the gear.
In addition, 7th gear is very much a driving gear for reaching top speed and not an
additional gear (overdrive) for reducing engine speeds while driving with a high-comfort
driving style as on the 911 Carrera models. Together with the 15% shorter finaldrive
ratio, the new 911 GT3 also has much shorter total gear ratios.

The selector lever gate was also adapted for the new 911 GT3. To visually differentiate
the particularly sporty character of the Porsche Doppelkupplung (PDK), the selector
lever gate has a central double stripe in black. The trim surround of the selector
lever gate was also adapted. In addition to being more purist with no additional selector-
lever positions (P, R, N and D), the selector lever gate features a “GT3” logo and
on the left-hand side, the designations “+” and “–” in Red for manual gear selection.
The display of the selector-lever positions P, R, N and D on the selector-lever release
button and in the tachometer is unchanged.
The shifting direction for manual gear changes on the selector lever is completely
new. Unlike all shifting directions for Tiptronic and PDK transmissions used by
Porsche, the shifting direction used on the new 911 GT3 is based on professional
motor sports. As a result, upshifts “+” take place backwards and downshifts “–” take
place forwards. This shifting direction is used because of the ergonomic and physical
conditions involved in a gear change.
If the driver shifts down in gears while driving on the race circuit and braking sharply
coming into a bend, forward downshifting supports ergonomic gear changes in accordance
with the law relating to the mass moment of inertia. The same applies when
accelerating out of a bend. In this case, the mass moment of inertia supports backward
upshifting.
The PDK functions, including gear indicator, are displayed in the tachometer on the
instrument cluster as on the 911 Carrera models. The actuation direction of the manual
shift display “+” and “–” was modified due to the change in shifting direction specific
to the GT3. The omission of the SPORT and SPORT PLUS function used on the
911 Carrera models and enhancement of the display strategy means that no PDK
functions are displayed in the SportDesign steering wheel on the new 911 GT3.

In addition to the short gear ratios and the short actuation travel of the shift paddles,
Porsche Doppelkupplung (PDK) is characterized above all by its unique gearshift
strategies and its short response and shifting times (including “lightning shifts”).
These characteristics ensure a performance-oriented gearshift behavior with particularly
sporty gear changes. The most important driving functions of the Porsche Doppelkupplung
(PDK) are based on the strategies of the current 911 Carrera models.
For differentiation and in order to adapt to the particularly sporty character of the
new 911 GT3, new functions have been introduced and modified functions and specific
fine-tuning measures implemented.
The following main development objectives were taken into account here:
• Increasing performance
• Reducing complexity
• Improving interaction between driver and vehicle
• Enhancing emotionality
Increased performance is achieved with the following features:
• Lightning shifts with very short response and shifting times
• Performance-oriented adaptation of gear preselection
Reduced complexity is achieved with the following features:
• No special functions, such as Coasting, Auto Start Stop, ECO upshifts
• Two driving modes: SPORT (basic setting) and “PDK SPORT”
• Special functions, such as Launch Control, are available irrespective of driving
mode
• No kickdown
Increased interaction between driver and vehicle is achieved with the following features:
• Selector-lever position “M” as an uncompromisingly manual shift function
• “M” with no automatic shift functions
• “M” with maximum acceptance of gearshift commands even during extreme engine
speed-oriented driving
• “Paddle Neutral” with additional function based on a conventional clutch pedal
Enhanced emotionality is achieved with the following features:
• Adaptation of the basic gearshift strategy to performance-oriented driving dynamics
without additional actuation of driving mode buttons
• Adaptation of the one-touch direction on the selector lever to motor sports
• Possibility of driving off with increased wheel slip with “Paddle Neutral”
• Possibility of influencing driving dynamics individually with “Paddle Neutral”
• No crawling without pressing the accelerator pedal

kosmo

IIRC the Scud shifts are really fast like 80 ms.

anything measured in milliseconds is fast

FLT6SPD

We do electrical testing on circuit breakers and protection relays and the reaction times for an instantaneous trip function (no intentional delay) is 40-50ms. Doing this on a daily basis you can tell when something is out of specification by 10-20ms without looking at the data.

With everything that is taking place mechanically 100ms is quick, 80ms on the scud that kosmo mentions is a mechanical marvel.

Drifting

Do you have a reference? I don't think the scud shifted that fast.

Zulu Alpha

In addition to what Mike in CA has so kindly referenced, that what the literature doesn't tell you about PDK-S is that the take up of the clutch is much more abrupt and crisper than PDK. Additionally, while driving slow with each shift, the clutch engagement and disengagement is much more abrupt.

vf430

Its actually faster than 80 ms. Its 60 ms f1 superfast 2 is one of the fastest shifting single clutch systems made for production cars.
http://en.m.wikipedia.org/wiki/Ferrari_F430
Scroll down to scud portion , btw its common knowledge in ferrari world. I have 10 k driving miles on that trans, its amazing.


"The latest F1 Superfast 2 software is employed for the 430 Scuderia's electro-hydraulic F1 gearbox. It is thus the road-going Ferrari with the fastest change time ever, with the entire gearchange operation – which in Ferrari parlance means the time power is removed then re-applied to the driven wheels, not just the time to change gears – taking just 60 milliseconds. That’s close to F1 times of around 40 ms."

http://www.ferrariapproved.com/en_GB...i-430-Scuderia

Aventador isr trans is supposed to have 40 ms shift speeds but i am not too familiar. I have had the 981 cayman s pdk , it felt just as fast as scud. I am picking up my gt3 tommorow i expect it to be as fast or faster thsn scud shifts. After a certain point they all are so fast i cant tell. Porsche saying new pdk s is under 100 ms is puzzling , its got be a lot faster when its comprable to 458 dct 40 ms.

fxz

i had both
PDK-S is the gearbox every 991 should have

shorter faster clever

but apart the numbers is the feeling
it makes me feeling i bought a sportcar and not an audi stationwagon

golfnutintib

...or to summarize, it's noticeably 'sportier'...

Shahano

thanks for the info.. quite interesting.

Peterfirst

From an engineering point of view the questions for me is: „how do you define shift times“?

Does anyone know if there is a standard which defines this and if the “official” figures from manufacturers are measured in accordance with a standard? Actually I don’t think so.

So how to compare shift times of a single clutch (automated manual) gearbox to a double clutcher?

Two different animals I think. Advantage of PDK is the fact that you can have the shifts without a lot of time interrupting the power going to the wheels. One clutch can open while the other one is already closing at the same time which actually gives the seamless shifts. So even if the claimed 60 ms are faster (does it mean from starting to open the clutch until the clutch is closed again or is it “just” the time needed to swap the cogs?) than the questions is how long is the power interrupted and that is what really counts.
But I guess that would be too complex to understand for the “average Joe” and marketing speak always likes to simplify.

Me also thinks the Italians like to show off – they might haven choose on intention the best possible times they could “justify” ….

Peter

I am prob a bit biased being an Germany engineer

Alan C.

And if you really want to feel the difference do a back to back in a 997.2 PDK and the GT3 PDK-S.

kosmo

its been a while since i've driven a Scud but I cant tell difference in speed. its just too fast for me to notice.
the PDKs is way smoother when putzing around in city traffic but I think the single clutch stuff is inherently more rough.