What would you have done differently?
07-06-2017, 12:34 PM
#61
Burning Brakes
[QUOTE=Dewinator;14300570]The PDK does have slight efficiency and performance advantages yes. SLIGHT.
Just to clarify these assertions, the PDK does achieve slightly better numbers on the EPA fuel economy tests, but that's only because at light throttle it upshifts at lower rpm than the manual transmissions are required to shift, by the test procedures.
If you are interested in fuel economy and shift the manual at the same rpm as the PDK, you will get the same or better fuel economy. After all, the manual has exactly the same ratios--at least in a 991.2--and it's lighter and has no parasitic losses caused by driving the hydraulic pumps needed to operate the PDK.
As to performance, there's no question that the PDK shifts faster, but the major performance advantage is in acceleration form a standing start. The PDK allows you to load the engine before getting rolling and this really helps launch the car. With the turbocharged 991.2s, where this procedure lets you build boost before launching, this is worth a great deal.
However, if you're on a road course rather than a drag strip, the PDK advantage is much smaller, particularly if compared with a well-driven manual.
Just to clarify these assertions, the PDK does achieve slightly better numbers on the EPA fuel economy tests, but that's only because at light throttle it upshifts at lower rpm than the manual transmissions are required to shift, by the test procedures.
If you are interested in fuel economy and shift the manual at the same rpm as the PDK, you will get the same or better fuel economy. After all, the manual has exactly the same ratios--at least in a 991.2--and it's lighter and has no parasitic losses caused by driving the hydraulic pumps needed to operate the PDK.
As to performance, there's no question that the PDK shifts faster, but the major performance advantage is in acceleration form a standing start. The PDK allows you to load the engine before getting rolling and this really helps launch the car. With the turbocharged 991.2s, where this procedure lets you build boost before launching, this is worth a great deal.
However, if you're on a road course rather than a drag strip, the PDK advantage is much smaller, particularly if compared with a well-driven manual.
07-06-2017, 12:48 PM
#62
Like many, bought my first one CPO and would've kept it had I not gotten PDK - experimented to see if I wanted it after having a manual E92 that frankly wasn't as good as DCT. But regretted it almost a month later, so I traded mine for a soon to be delivered .2 GTS with manual.
07-06-2017, 01:09 PM
#63
[QUOTE=Valvefloat991;14303679]
You must be a really good manual driver... after driving manuals all of my life I would never come close to the PDK in efficiency...
And if you are tracking, the PDK in Sport+ is far better than what I would never be able to achieve.
You must be a really good manual driver... after driving manuals all of my life I would never come close to the PDK in efficiency...
And if you are tracking, the PDK in Sport+ is far better than what I would never be able to achieve.
07-06-2017, 03:33 PM
#66
Burning Brakes
Oh, yes you fully intended that, or you wouldn't have made the original comment. "I don't see any regrets over manuals" is very much a manual über alles remark, and inherently pointless otherwise.
I don't really understand the need of some manual drivers to do this. Many of us who drive PDK have driven manual, automatic, and PDK, and know full well the advantages and drawbacks to all of 'em. Heck, if you go back to what I said about my car, I mentioned that I felt a bit about ambivalent about going PDK after 17 years of driving manual. I don't see the point of making "camps" out of the two transmissions and mocking the other camp.
Rowing the gears is more fun, I know that, you know that, we all know that. But harping on the "slight" performance advantage of PDK? You must be some kind of race car driver, because I've never come close to shifting half as fast as the PDK. It's silly-fast, and it seems off to pretend it isn't.
A far better argument is that most of us aren't tracking our cars, and don't need lightning-fast shifts to enjoy the car.
I don't really understand the need of some manual drivers to do this. Many of us who drive PDK have driven manual, automatic, and PDK, and know full well the advantages and drawbacks to all of 'em. Heck, if you go back to what I said about my car, I mentioned that I felt a bit about ambivalent about going PDK after 17 years of driving manual. I don't see the point of making "camps" out of the two transmissions and mocking the other camp.
Rowing the gears is more fun, I know that, you know that, we all know that. But harping on the "slight" performance advantage of PDK? You must be some kind of race car driver, because I've never come close to shifting half as fast as the PDK. It's silly-fast, and it seems off to pretend it isn't.
A far better argument is that most of us aren't tracking our cars, and don't need lightning-fast shifts to enjoy the car.
07-06-2017, 05:55 PM
#67
Burning Brakes
I don't want to feed this flame war either, as the choice of manual over PDK is highly subjective. But it worth considering some facts. Car and Driver has tested 991.2 C2s with both manual and PDK transmissions. Here are the test results:
M7 PDK
0-30 1.7 1.3
0-60 4.0 3.4
0-100 9.1 8.5
0-130 15.1 14.8
0-150 21.5 21.9
The PDK is clearly quicker almost everywhere. However, the major benefit is at the launch because the PDK lets you build boost before blasting off and with Sport-Chrono, which this car had, it also has launch control. With the manual, all you can do is drop the clutch to try to get the engine into its power band before the spinning tires hook up. Because the 991.2 won't let you drop the clutch above 4200 rpm, this is impossible and the M7 car's acceleration suffers.
But if you take out the launch and look at intermediate speeds, here's what you get:
M7 PDK
30-130 13.4 13.5
60-100 5.1 5.1
100-130 6.0 6.3
100-150 12.4 13.4
Now these cars weren't tested back-to-back on the same day and at the same track, but the test results were weather-corrected and are probably in the ballpark. That's why I contend that, unless you're a drag racer, the performance benefits of PDK are minimal and offset by the additional weight and parasitic drag.
M7 PDK
0-30 1.7 1.3
0-60 4.0 3.4
0-100 9.1 8.5
0-130 15.1 14.8
0-150 21.5 21.9
The PDK is clearly quicker almost everywhere. However, the major benefit is at the launch because the PDK lets you build boost before blasting off and with Sport-Chrono, which this car had, it also has launch control. With the manual, all you can do is drop the clutch to try to get the engine into its power band before the spinning tires hook up. Because the 991.2 won't let you drop the clutch above 4200 rpm, this is impossible and the M7 car's acceleration suffers.
But if you take out the launch and look at intermediate speeds, here's what you get:
M7 PDK
30-130 13.4 13.5
60-100 5.1 5.1
100-130 6.0 6.3
100-150 12.4 13.4
Now these cars weren't tested back-to-back on the same day and at the same track, but the test results were weather-corrected and are probably in the ballpark. That's why I contend that, unless you're a drag racer, the performance benefits of PDK are minimal and offset by the additional weight and parasitic drag.
07-06-2017, 05:59 PM
#68
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I don't want to feed this flame war either, as the choice of manual over PDK is highly subjective. But it worth considering some facts. Car and Driver has tested 991.2 C2s with both manual and PDK transmissions. Here are the test results:
M7 PDK
0-30 1.7 1.3
0-60 4.0 3.4
0-100 9.1 8.5
0-130 15.1 14.8
0-150 21.5 21.9
The PDK is clearly quicker almost everywhere. However, the major benefit is at the launch because the PDK lets you build boost before blasting off and with Sport-Chrono, which this car had, it also has launch control. With the manual, all you can do is drop the clutch to try to get the engine into its power band before the spinning tires hook up. Because the 991.2 won't let you drop the clutch above 4200 rpm, this is impossible and the M7 car's acceleration suffers.
But if you take out the launch and look at intermediate speeds, here's what you get:
M7 PDK
30-130 13.4 13.5
60-100 5.1 5.1
100-130 6.0 6.3
100-150 12.4 13.4
Now these cars weren't tested back-to-back on the same day and at the same track, but the test results were weather-corrected and are probably in the ballpark. That's why I contend that, unless you're a drag racer, the performance benefits of PDK are minimal and offset by the additional weight and parasitic drag.
M7 PDK
0-30 1.7 1.3
0-60 4.0 3.4
0-100 9.1 8.5
0-130 15.1 14.8
0-150 21.5 21.9
The PDK is clearly quicker almost everywhere. However, the major benefit is at the launch because the PDK lets you build boost before blasting off and with Sport-Chrono, which this car had, it also has launch control. With the manual, all you can do is drop the clutch to try to get the engine into its power band before the spinning tires hook up. Because the 991.2 won't let you drop the clutch above 4200 rpm, this is impossible and the M7 car's acceleration suffers.
But if you take out the launch and look at intermediate speeds, here's what you get:
M7 PDK
30-130 13.4 13.5
60-100 5.1 5.1
100-130 6.0 6.3
100-150 12.4 13.4
Now these cars weren't tested back-to-back on the same day and at the same track, but the test results were weather-corrected and are probably in the ballpark. That's why I contend that, unless you're a drag racer, the performance benefits of PDK are minimal and offset by the additional weight and parasitic drag.
I would have gotten a manual but couldn't find the deal I got at the time and now love my pdk. At least I didn't get stuck with little ticking hair dryers...
07-06-2017, 07:19 PM
#69
4th Gear
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If those intermediate speeds are correct, and PDK tends to be actually slightly slower on anything that isn't a launch, why does it seem that most lap time records are made with cars with PDK (or corresponding dual clutch in AMG/Ferrari etc.)? Seems like many race tracks have long enough laps that the initial launch advantage of the PDK would quickly be meaningless...
Is it because even race track drivers benefit from being able to focus on one less thing to do? Is the parasitic loss less of an issue for cars stronger than the C2S?
Seems to me that if the 7M truly were faster or even in the same ballpark, Porsche wouldn't have pushed GT3 etc. towards PDK only (until recent change of heart due to customer demand...).
Not trying to fan the flames, just trying to understand how those intermediate speeds fit in.
Is it because even race track drivers benefit from being able to focus on one less thing to do? Is the parasitic loss less of an issue for cars stronger than the C2S?
Seems to me that if the 7M truly were faster or even in the same ballpark, Porsche wouldn't have pushed GT3 etc. towards PDK only (until recent change of heart due to customer demand...).
Not trying to fan the flames, just trying to understand how those intermediate speeds fit in.
07-06-2017, 08:47 PM
#70
SJW, a Carin' kinda guy
Rennlist Member
Rennlist Member
On a race track you shift a lot and PDK makes shifts faster than anyone can shift a manual. In a rolling x-y mph you may have maybe one or two shifts tops so it is less of an issue. PDK weighs more so that also has a negligible impact especially at the higher speeds.
Biggest issue is PDK costs money as an option on anything other than a GT car and PDK makes sport chrono a very worthwhile option. All in that is real money to the indifferent, let alone a die hard three pedal guy like me.
Biggest issue is PDK costs money as an option on anything other than a GT car and PDK makes sport chrono a very worthwhile option. All in that is real money to the indifferent, let alone a die hard three pedal guy like me.
07-07-2017, 12:46 AM
#72
Burning Brakes
[QUOTE=R_Rated;14304536]Your data is bananas to bricks comparison. One set of specs shows 0-60 and the other rolling speed to higher speed.
Each data includes both the M7 and the PDK numbers. I inserted spaces to try to achieve a neat columnar display, but it didn't come out that way. But both data sets are direct comparisons.
I can't deny that PDK tends to produce somewhat quicker lap times. Perhaps it's due to the reduced effort/distraction required to execute fast and seamless shifts. Perhaps it's the consistency of the PDK shifts.
But in pure acceleration, at any rolling speed, PDK does not appear to be measurably quicker. I am open to examining other data.
But as a former engineering boss used to say, without data, you're just another opinion.
Each data includes both the M7 and the PDK numbers. I inserted spaces to try to achieve a neat columnar display, but it didn't come out that way. But both data sets are direct comparisons.
I can't deny that PDK tends to produce somewhat quicker lap times. Perhaps it's due to the reduced effort/distraction required to execute fast and seamless shifts. Perhaps it's the consistency of the PDK shifts.
But in pure acceleration, at any rolling speed, PDK does not appear to be measurably quicker. I am open to examining other data.
But as a former engineering boss used to say, without data, you're just another opinion.
07-07-2017, 02:59 AM
#73
Rennlist Member
I looked daily and nationally for 4 months and found almost exactly what I wanted, so really nothing.
18-way manual seats would be nice, with rear parking sensors.
18-way manual seats would be nice, with rear parking sensors.
07-07-2017, 08:07 AM
#74
Drifting
The reason PDK is faster for me on track (where you're not even doing any standing-start acceleration where Launch Control can come into play) is simple: 911 GTS needs to be shifted at redline for max power under the curve. Even using PDK in Sport+ Manual, I can never execute perfect 7800-rpm shifts time after time after time. I either bang the rev limiter and waste time recovering, or I short shift a bit and leave a few hundred rpms on the table. Same is true using a 6M with clutch, only likely worse.
With Sport+ Automatic, the shifts are spot-on 7800 rpm masterpieces every single time, and I can focus on those pesky other driving chores.
With Sport+ Automatic, the shifts are spot-on 7800 rpm masterpieces every single time, and I can focus on those pesky other driving chores.
07-09-2017, 12:11 PM
#75
Racer
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I'll jump in on the PDK/Manual discussion. I had a manual Cayman S 981 (after a manual 987). I was perfectly happy with it. then went to a track/DE event fro the first time ever and was in a group of beginners that were all the same car but with PDK. During the two days of that event I learned what a PDK meant to the track, and it was a big deal. Probably depends greatly on the track. On this particular one, you never really have to get out of 3rd gear in a manual. The speeds you got to make it so you probably shift 3 times max around the track if you are in a manual car, but the PDK must have been doing some magic to be finding the appropriate gears far more often that i was. i was getting beat pretty bad by the PDK cars, even with one being just a base model. I found out that I could either learn to be a better manual driver, or i could learn to corner better, and if I opted for the PDK next time, i knew i would become much better at track driving much quicker as I could focus on cornering and know that the car is already doing the gears better than i could anyway. So when i switched to the new 991.2 I got the PDK.
Alas, now that i have this car i have been afraid of wreaking it at the track, so i just daily drive it and now i miss my manual. not sure what i would do next time. But i'm feeling it will be a manual with the Sport Chrono, Sport exhaust, and that's about it. Then, I'll probably track that one and wish it would have been a PDK... I'll certainly wish it was a GT3.
Alas, now that i have this car i have been afraid of wreaking it at the track, so i just daily drive it and now i miss my manual. not sure what i would do next time. But i'm feeling it will be a manual with the Sport Chrono, Sport exhaust, and that's about it. Then, I'll probably track that one and wish it would have been a PDK... I'll certainly wish it was a GT3.