Any regrets going with a PDK tranny??
#16
Not to mention the fact that the drivetrain packaging is inverted with the transmission ahead of the engine in the Carrera and behind it in the Boxster. Whether that difference, or the possible internal changes required to handle the added power as you point out, have anything to do with the price difference, is a matter for conjecture.
#17
Ya'll believe what you want to believe. I can't believe there's any fundamental differences in the PDK between the 991 and 981 series. It simply wouldn't be cost effective to have two completelty different transmissions for two cars that share lots of parts and technology already.
#18
Ya'll believe what you want to believe. I can't believe there's any fundamental differences in the PDK between the 991 and 981 series. It simply wouldn't be cost effective to have two completelty different transmissions for two cars that share lots of parts and technology already.
#19
Ya'll believe what you want to believe. I can't believe there's any fundamental differences in the PDK between the 991 and 981 series. It simply wouldn't be cost effective to have two completelty different transmissions for two cars that share lots of parts and technology already.
FWIW, it's been widely published that PDK in the new 991 GT3 is going to be upgraded and modified for that application, so at least it's not unthinkable that there might be differences between PDK in the Boxster and the Carrera.
#20
Even if there is a difference, does it cost Porsche $1000 extra? Probably not, but...
To compare a couple of other items:
Park Assist (front+rear): Caymen $860 Carrera $990
Rear wiper: $360 $360
Is it $130 more difficult to implement Park Assist on a Carrera? Maybe because it's so big? But it does imply that there is a larger design/parts difference on the PDK and PA than on the wiper, for example, which otherwise should cost $500 on the Carrera just for good measure.
Or not, who knows, since performance related parts seem to get a premium stuck on them.
To compare a couple of other items:
Park Assist (front+rear): Caymen $860 Carrera $990
Rear wiper: $360 $360
Is it $130 more difficult to implement Park Assist on a Carrera? Maybe because it's so big? But it does imply that there is a larger design/parts difference on the PDK and PA than on the wiper, for example, which otherwise should cost $500 on the Carrera just for good measure.
Or not, who knows, since performance related parts seem to get a premium stuck on them.
#21
Probably because they have to drop the engine. Engine doesn't get in the way in the rear of the Cayman.
#22
regret
i had a tip in my boxster s and didnt like it - said i would never get another one just because it takes away from the " fun" of driving!! altho i do have it on my cayenne ( mainly for the wife) i wont get a pdk on my next 911 this year. besides the " safety" limits designed into the tranny wony let u operate it like a true auto/ manual!
#23
I had a PDK in my 997.2 and now another in my 991S. They are both waay smarter than I am, but the 991PDK seems more intuitive. I may do a factory delivery car this summer and it will have PDK as well. With that said, I really love driving my old 993 with its manual trans.
#24
i had a tip in my boxster s and didnt like it - said i would never get another one just because it takes away from the " fun" of driving!! altho i do have it on my cayenne ( mainly for the wife) i wont get a pdk on my next 911 this year. besides the " safety" limits designed into the tranny wony let u operate it like a true auto/ manual!
#25
i had a tip in my boxster s and didnt like it - said i would never get another one just because it takes away from the " fun" of driving!! altho i do have it on my cayenne ( mainly for the wife) i wont get a pdk on my next 911 this year. besides the " safety" limits designed into the tranny wony let u operate it like a true auto/ manual!
#27
I have to pay $4660 for PDK north of the border in my 991S. For what? Don't even get me started on the whole US/Canada pricing discrepancy. The exchange is quite close to par. I know, US is a bigger market...blah..blah...
#28
i had a tip in my boxster s and didnt like it - said i would never get another one just because it takes away from the " fun" of driving!! altho i do have it on my cayenne ( mainly for the wife) i wont get a pdk on my next 911 this year. besides the " safety" limits designed into the tranny wony let u operate it like a true auto/ manual!
#29
Porsche sourced the PDK's from ZF and two dual-clutch transmission platforms were developed by them for Porsche. Moreover, each platform comes in two different torque ratings, using the ND2015 clutch pack for applications up to 500 newton-meters and the ND2216 up to 780 nm. That gives four basic transmissions.
To further complicate matters, a dual-clutch transmission is not like a conventional automatic that normally has fixed ratios. Like a race car box, the DCT can be built with different ratios according to the target application. That means four basic variants, with each tailored to Porsche's specification as their vehicle models require.
Let's discuss software in a minute. First, those primary mechanicals. The ZF number for this transmission family is 7DT and it is developed by ZF to Porsche specifications.
The first platform is for the sports cars. Originally, this platform did not include stop-start capability, but that has been added for the 991 cars. It has two oil circuits with one oil specified for the hydraulics and clutch pack and another for the gear-set and bevel gear.
45HL 500N.m Porsche 911
45HLA 500N.m Porsche 911 4-Wheel-Drive
45FL 500N.m Porsche Boxster and Cayman
70HLA 780N.m Porsche 911 Turbo
Boiling that down, the All-Wheel-Drive cars require their own transmission variation; the most powerful engines get the 780-nm-rated clutches (et al) versus the 500-nm rating; and the 911 family get the HL model while the Boxster and Cayman get the FL model. (No. I have no idea what distinguishes them. Only educated guesses that several of us could make.) My source article was written before the 991 release and obviously before the variants like the Turbo S and the GT3 RS 4.0, but it's easy to see the choices and guess which has which.
The second platform uses only a single oil circuit and a dry sump to minimize churning losses. It is distinguished by features like the ratio spread of 10:1 that allows very low engine speeds at cruise, originally by its stop-start provision, and by the fairly unusual layshaft mounting that is above the input shaft rather than below. This was required by Porsche specifications like "narrow with a high tunnel" and presumably aids them in keeping the Pannie's center of gravity low.
75 500/780N.m Porsche Panamera
75A 500/780N.m Porsche Panamera 4-Wheel-Drive
I don't really know why the source document specifies the torque as "500 slash 780 nm" but we can guess that it was published before the high output Pannie engines were introduced. That is, the Turbo and Turbo S at least. Obviously, the six gets the 500 nm clutch pack and the turbos get the 780 nm. We have to guess about the eight-cylinder but a quick check of the spec's probably would settle it.
I don't follow the non-sports cars much, but I thought the Cayenne had a PDK option as well, doesn't it? If so, I would expect it to get the second platform, the 75 or 75A, with clutches in an torque rating appropriate to the engine.
Software...
ZF and Porsche develop the software jointly. I have no source documents on this and I don't expect to see any unless Porsche asks for help. (Do we have a snicker icon? How about ) From reports of owners of both generations and from coy references in various texts, I infer changes in the number of control maps and in the number of system inputs examined when selecting a control map.
In the trade articles, this 7DT family is described as being a mood-sensing transmission. (Swear to God. In a mundane, down-to-earth category like transmission periodicals: "mood sensing". That's what comes of letting engineers take classes on the squishy end of campuses.) That term is justified, as we owners have noticed. The obvious items influence the control maps, like the sport and sport-plus buttons; and the usual-in-the-trade inference of road-surface condition so that shifts are tailored to available traction. These transmissions add inputs for lateral and longitudinal acceleration, for steering angle, for throttle pedal angle. By my own inference, without a source I can quote, Porsche also seem to measure time-between-control-action to arrive at inferred driver skill level. Whether that value is used only in vehicle dynamics systems I cannot judge, but it could create another 'discrete' as we call them, a simple true-false input for the transmission control unit that amounts to "driver knows what is needed, don't doubt other inputs". Phrase that last one however you like. Hot-shoe vs twitchy-novice or your choice.
Other features that Porsche required are extremely long service life and limp-home capability. ZF designed and produces these units with a goal of lifetime oil fill. For conservatism, Porsche downgrades that to 90,000 kilometers between transmission oil changes. The limp-home ability is by no means a given with DCT transmissions. If they lose oil pressure, most designs cannot keep a gear engaged so the car is parked, *****-nilly. These units use a proprietary valving system (that also aids stop-start capability) that allows limited capability if you're somewhere you really don't want to sit and wait. Been there, done that. I applaud.
What was the question? Oh yes. No, it is not the same box in every car.
Gary
Last edited by simsgw; 01-09-2013 at 11:22 PM. Reason: Typos
#30
I'm a Limey and one of the things I love about America is you can get just about what you want
I'd you are prepared to pay for it
the PDK/MT seems to take on an almost religious warfare type tone at times
that I don't get.
I love my PDK with chrono. I really like the fact that I have options.
I can leave it in regular or sports mode, but can change gear manually If
so desired. I can put it in sports plus but can also
manually intervene if so desired. this is my favored current mode
when running back roads where if I left it in full auto I would be spending
a lot of time running at redline in 2nd
this works for me, but I totally get someone wanting the satisfaction of a
MT.
to me people extolling theorist of PDK over a MT is akin to arguing over
what color you want. try both and pick the one you like and god bless America
that you have that option.
I'd you are prepared to pay for it
the PDK/MT seems to take on an almost religious warfare type tone at times
that I don't get.
I love my PDK with chrono. I really like the fact that I have options.
I can leave it in regular or sports mode, but can change gear manually If
so desired. I can put it in sports plus but can also
manually intervene if so desired. this is my favored current mode
when running back roads where if I left it in full auto I would be spending
a lot of time running at redline in 2nd
this works for me, but I totally get someone wanting the satisfaction of a
MT.
to me people extolling theorist of PDK over a MT is akin to arguing over
what color you want. try both and pick the one you like and god bless America
that you have that option.