Engine oil type and viscosity, method of fill, change intervals are the same as for the MT Carerra.

For the PDK tranmission itself from the Porsche Technik information on PDK:

Due to high shearing strains that occur in the differential, two different oil chambers are used in the Porsche Doppelkupplung transmission.

The oil chamber for hydraulic oil is shown in red, while the oil chamber for gear
wheel oil is shown in blue in the illustration above.

2.95 liters of Mobilube PTX Formula A (SAE 75W-90) GL4.5 are used in the transmission for lubricating the gear wheel set. 5.2 liters of Pentosin Gear Oil FFL3 are used as hydraulic oil.

The change interval is 56,000 miles (90,000 km) for hydraulic oil and 112,000
miles (180,000 km) for gear wheel oil.

 

sorry i guessed you missed my poor attempt at humour (i have been on the 993 board too long!!)

 

Nobody is going to agree on which transmission is "better" because "better" relies on what criteria are important to each person. For instance, some people might say a Toyota Camry is "better" car than a 911 because the Camry has more trunk space, and trunk space is more important than handling/acceleration to that person. But by looking at objective criteria, we can determine that the 911 is a higher performance vehicle. We can look at things like 0-60, quarter mile, lateral acceleration, track times etc.

For transmissions, I think we can apply the same tests. Sure, a manual box is "more fun," but is it a higher performance transmission? Well let's see. These are the criteria I think are important:

1) Shift Time - A higher performance transmission can perform its task (i.e. shifting gears) faster. PDK can change gears in 40-200 milliseconds. Gear shift occurs significantly and noticeably faster than a manual.
Advantage: PDK

2) Power Loss Between Shifts - A higher performance transmission loses minimal power between gear shifts.
PDK has virtually no power loss. The currently selected gear is released while the next, pre-selected, gear is simultaneously engaged. Even a perfectly executed manual shift cannot compare to a dual-clutch configuration.
Advantage: PDK

3) Overall Acceleration - A higher performance transmission will allow the vehicle to accelerate faster because it is more efficient in transmitting engine power to the wheels.
As discussed, PDK 0-60 on the C2S is 4.3 sec vs. 4.5 sec for manual. This is a significant difference and can mean a difference of several feet during a short <5sec drag race. The more shifts that take place during a hypothetical race, the more the small disadvantage of the manual, in terms of shift time and power loss, will add up.
Advantage: PDK

4) Accuracy of Shifts - A higher performance transmission will minimize the possibility of inefficient shifts, mis-shifts, and the shifts that can damage the engine. "To err is human." Not even the seasoned professional driver will be able to execute each shift perfectly during every drive. God forbid one accidentally shifts from 4th to 1st at freeway speed. Then there's the issue of over-revs on a manual. Just one shift at the wrong rpm and the perfectly-shifted PDK will pull ahead. Systems that do not allow humans to introduce their known tendency to err are generally more efficient and safer. This is one of them.
Advantage: PDK

There are other advantages/disadvantages of PDK vs. manual. There are differences in fuel efficiency, ease of use, ability to drive with 2 hands on the wheel, and the subjective determination of which is more "fun." These are all important to which transmission an individual might personally prefer, but I think the above 4 criteria are what determine the performance of a transmission.

I think it's very clear that the PDK, using objective criteria, is a higher performance transmission than the manual in the 997. Whether or not the PDK is an individual's preference may not be the same (i.e. if tradition and subjective sensation of "fun" and "engagement" are more important than the actual performance capabilities of the transmission itself.)

 

Objective?

 

You got me. Actually it occured to me that you might be joking but people ask silly questions sometimes and rather than risk insulting them if they're being serious I usually just try to answer and be helpful instead of telling them their question was stupid. My bad for trying to be a nice guy......

Very nice analysis, gasongasoff. I would only add that the advantages PDK has in the 4 areas you outlined are also part of the reason why it's also a lot of fun to use PDK.

 

Mike, there are no "ignorant a$$h%les" here, just smart a$$h%les.

 

Have to say that the OP started this whole thread out to assertain whether the fun factor, enjoyment level, involvement with the car is still there and what exepriences those that have PDK are having. Also whether or not they tend to laps into the ease of just leaving it in auto "D" after a while or whether they tend to stay involved with the car by using the manual options either thru the stick or the paddle shifters. This thread is getting back to the older argument for which I don't believe there is any objective answer - that is which is better. Not the stay on track police but it's nice to stay on topic a bit.

But on the other hand what I found interesting is that when they opened up that tranny that had been used in racing with PDK to change out the clutches - they didn't need too! NOW that is technology that you can sink your teeth into - the one that doesn't effect the pocket book. Know what else - in that race car there was no degredation or infiltration due to an internal seal failure of the gear oil and hydraulic oil!!!! I don't know about you guys but the longevity factor of the PDK seems to be at this point really super and that my friends has got to be a huge bit of the old "peace of mind" factor. Makes you think someone really worked on that design very hard - much harder than the constant issues that have plagued both 996 and 997s with RMS failures. Nice to see a new tranny that isn't displaying tempermental issues or the proverbial "achilles" heel! I am most encouraged by that I'll tell you.

For example; the other month I was invited by my local Porsche dealer to an event that allowed us to drive 4 different autos on the end of a runway at P'tree Dekalb airport. The Boxster had PDK, the Panamera had PDK, the Carrera had MT, the Cayenne had PDK I believe. Anyway - everyone wanted their turn with the Carrera right - take it thru those cones, see what it'll do, etc. - well after a lot of spirited use when I got up to the car for my turn - guess what I could smell - yep - the clutch! Had suffered a bit under the abuse of shifting by novices - I could hear it - lots of folks really don't know how to shift very well - another story - but the PDK equipped cars exhibited none of that! Just like this race car team that is using the PDK - guys that's just one more reason I think to put a + sign or positive check by the PDK list of strengths and "weaknesses" - and that ain't nutin to sluff off!

We all know about expenses associated with maintaining these exotic sports cars and Porsche is certainly no exception. Anything that assists longevity and lower costs due to maintenance intervals and part replacement intervals is absolutely HUGE in my opinion. Some may sluff that off as entertainment funds and to be expected like a few points made in the post started by Gsims on the PDK - but some of us are a little more, shall we say, economically minded. I'm liking the PDK more and more with every post!

 

tbrom, the excerpt below from Porsche's technical introduction to the PDK is relevant and might be of interest to you because it supports your comment. Some may dismiss this as marketing hype, but the point is that Porsche has been working with PDK gearboxes for a long time and they did wait until they could get it right before they put it in a road car.

BTW, PDK isn't available in the Cayenne; it uses a new but conventional 8-speed Tiptronic gearbox.


Porsche has worked with Doppelkupplung transmissions since the '70s. The first racing car with PDK was used in 1984 in the Porsche 956 at Nürburgring, while Porsche had its first big win with a PDK transmission in 1986 with the enhanced 962 in Monza. The main advantage over rival vehicles was that gearshifts could be accomplished without interrupting tractive power. This allowed shorter shifting times with significantly improved acceleration for the racing car. This type of transmission proved successful during the highly challenging long-distance World Championships, although two dry clutches were used. The high level of lining wear associated with this type of clutch was not an issue since the clutch plates would be replaced immediately after each race.

Standard development was not followed up at that time as control electronics systems and computer capacities in the '80s were not yet sophisticated enough to perform the complex control functions that were essential to meet the comfort requirements for road vehicles. Also, the mechanical control elements for precise hydraulic valve control were not yet fully developed or financially viable at that time.

The Porsche Doppelkupplung transmission (PDK) is both a manual and automatic transmission. The special feature of PDK is that two gears can always be engaged one gear is engaged while driving and the next potential gear is already pre-selected. When shifting, the clutch on the active gear opens while the other clutch engages the pre-selected gear at the same time. This happens under load and so quickly that the power flow is permanently available.

Due to its fast gear changes without any significant power flow interruption, the 7-speed Doppelkupplung transmission offers much better driving dynamics than a conventional manual transmission, with the convenience of an automatic transmission. The superbly sporty driving dynamics are complemented by a high level of efficiency, which results in reduced fuel consumption compared with a conventional manual transmission in certain driving situations.

 

You say we can't define which is "better", yet you go on to say it is very clear that PDK is better.

Some reasons why I don't consider it a "higher performance" transmission:

- It is controlled by a computer. It may be smarter than other conventional and dual-clutch automatics, but it can be flummoxed and not give you the gear you want, when you want it. For example, taking a beat too long for comfort to drop down from top gear into the power band when shooting a gap in traffic, whereas with a manual you would already be in, say 2nd gear.

- It is heavier. Lighter = higher performance.

- Its default objective is fuel economy. With a manual transmission, you can go from calmly shifting to aggressively shifting and back without changing a series of settings. More control = higher performance in my book.

Bottom line is that it is an automatic transmission capable of ever so slightly quicker and more efficient shifts than other modern automatics due to its dual-clutch design and software programming.

 

But it is not a true automatic in the traditional sense and whether you prefer the MT to the PDK is pertinent to another discussion on this topic but not in line with this OPs original post - it is relevant though.

You have not addressed the longevity factor either and to me that is a big plus. I mean different people like MTs for a lot of reasons and not all that get an MT are seasoned shifters and may at their own expense find out the hard way. I would suggest that PDK, as said by Porsche management, is going to sell a lot more cars while still providing a very high level of involvment between the driver and the auto - the op is trying to substatiate that claim from those that are living with PDK on a daily basis and not those that see or don't see the benefits of PDK due to their own preferrence and reasoning for owning a MT.

That's my perspective. This topic has already been discussed by Panorama very well and we can discuss the benefits to MT vs PDK all day long and never really iron out an iron clad reason to go one way or the other for everyone. So maybe it would be fun for this particular exercise to try and find and discuss what those that have them find so damn good about them. I find that the longevity aspects are just one more plus to having the PDK - a side bar on hassle free ownership is a nice little perk I'd say!

Maybe we've gotten to the bottom of the fun equation but I don't think enough with PDK have answered here in the vien of the OPs original question to the group. When folks read this and jump in on the tail end of a 7 page discussion and it just seems like another one of those PDK vs MT discussion they may not comment.

To Mike's comment - I've read all the tech jargon and dealer provided stuff on the PDK - I believe that what we've found from those that are actually racing with the new PDK is real world reliability and you can't get that from Porsche's sales jargon. What I'm talking about here is real documentation to it's reliability and durability! That is invaluable info - albeit a tinsy tiny view - but racing puts strain and 10,000 miles of racing is amazing testimony to clutch pack durability not to mention seal reliability. We've all heard of the issues with the M96 engine with water mixing with oil over time. This is a very important piece of the puzzle for those looking for durability in their choice of sports car!

There have been posts on this forum in the IMS poll ongoing here from guys with 997.2 engines that don't know they don't have an intermediate shaft! Some just buy a 911 cause it's a status symbol or an impressive car from reading the jargon and a test drive - they don't know anything about the mechanicals and history of the maladies that have surfaced in almost every model run of the 911 and many have multiple issues.

In my opinion durability and maintenance free, problem free components and corrections due to technological improvements are paramount to any disscussion of the 911 but now I'm really turning this thread further from it's original intent myself. But an important side note I think - sorry for the "hi-jack".

 

I can't ever recall having experienced the scenario you describe. If you think you can clutch/downshift/declutch faster than I can engage 2nd manually with the paddle (which works either in M mode or any auto mode), or faster than PDK will downshift in Sport or Sport Plus with full throttle application, I think you are deluding yourself.


You got this one right. At 66 pounds heavier it's the one performance negative to PDK. I helped make up the difference by deleting my rear seats and ordering lightweight sport buckets.

A huge overstatement. The fact that PDK starts out in normal "economy" mode is about as relevant as the fact that it (or your MT) starts out in neutral. I buckle in, turn the key and shift into manual mode. Done. Or I start up and press Sport or Sport Plus. End of "changing a series of settings". Even if one leaves PDK in normal, which I rarely do, a quick stab of the throttle and it adapts almost instantly (at least as quickly as one can downshift a MT) to the input.

I respect the fact that you want a MT and understand why you prefer it. But to keep trying to suggest that it offers better objective performance seems futile.

 

False. D-Sport is actually quite good. But PDK shifts gears manually the same way one shifts gears in a manual 6-spped

There are other ways to save mass.


You've clearly never driven a PDK.

I say: Porsche's 6-speed manual is a great transmission. The difference is that you cannot bite your lip and say the same for the PDK. You have to tell the world that it is an 'automatic' in a depreciative tone and make sure, that your choice is the manly one. OK, I get it!

 

No Alan, I would not want to have the PDK on it. I would leave it the way it is w/out a PDK, a power steering, ABS, PTM, PASM, airbags or a functioning HVAC

 

Very informative responses. Nerds drive Porsches!

 

Looks like some can't keep from getting personal.
I am not. I am pointing out that PDK isn't necessarily "better". You yourself pointed out that Porsche's best driver is no faster around the 'ring in a PDK car, and Porsche states the C2S with PDK has a lower top speed. You can't cherry-pick 0-60 times and make the statement PDK "offers better objective performance". More importantly, I am also pointing out that choice of transmission is subjective.
Not once have I said PDK is not a great transmission. It is, and it is a huge improvement over the dismal 5-speed Tiptronic that came before it (I had one...actually two, as the first had catastrophic failure...in a 997 for almost 4 years). But they have the same user interface, and therefore are both automatically shifting transmissions. Read into the "tone" what you will. Not once have I said that a manual is more "manly", but, yes, it does take skill to master, and PDK doesn't; not sure how you could argue otherwise.