cvazquez

+1 well said... no wrong answers, it just happens that I like old school fun.

Alan Smithee

Actually, no. The "seat of the pants" would feel the same acceleration forces if the time is lost during the shift.

PDK is not going to get you three car lengths by 60mph. While you may travel 35ft in .4 seconds at 60mph, that does not mean you will be anywhere near 35ft ahead in a drag race to 60mph.

Alan Smithee

Poor analogy, Macster. Check the definition of 'classic'. PDK has been on the market for less than 3 years. You don't have to go back to WWI to have a 'classic' driving (or flying) experience.

Waxer

So let me understand...I would need to go back to a Model T "sport" for a true classic sports car experience or the Wright Bros For a classic flying experience?

For those that think they can feel .4 of a seconds difference in acceleration from the seat of your pants...I'm impressed but seriously doubt you could nor do I think such ability determines whether you should drive a sports car. And as pointed out to 60mph you would not be 35ft ahead. Furthermore around a track you better be better in braking, your lines, shift points etc..for PDK to put you ahead at the finish line apples to apples.

MTs have been standard fare in the worlds top sports cars for 40 years or so. Thus making it the "classic" combo and trans for sports cars. Perhaps in 40 yrs PDK will be considered a classic trans.

Mike in CA

I disagree. The time wasted during the shift is time that the PDK spends continuing to accelerate. That interuption of power flow is evident and overall, the PDK is going to subjectively feel faster accelerating not just because, in fact, it is faster, but because in virtually any road situation it responds more quickly to inputs, need to clutch and downshift first for max acceleration, speed of upshift, etc.

Very good point. My logic (and math) were both sloppy. You got me curious so I spent some time coming up with math that I think is more representative. For the calculations, I make the assumption that the rate of acceleration is constant. In fact we know that it will decrease the faster the car goes, but for the puposes of this example I think it's reasonable because a) the rate to 60 mph doesn't drop off that much and b) I'm comparing a Carrera S to a Carrera S not to some other car with different acceleration characteristics. Please check my math and I welcome your input.

A=VF-VI/T

where A = Acceleration
VF = Final Velocity
VI = Initial Velocity
T = Time
A for MT = 60-0/4.5 = 13.33mph/sec = .003695 mi/sec
A for PDK = 60-0/4.3 = 13.95mph/sec = .003876 mi/sec
A for PDK LC = 60-0/4.1 = 14.63mph/sec = .004065 mi/sec

So using the formula

S = VoT + (1/2)(a)(T^2)
where
S = distance travelled
Vo = initial velocity = 0
T = time travelled
a = acceleration

How far will each car have travelled in 4.1 seconds (the time it takes for the PDK LC to reach 60), and how far will they be behind PDK LC at that point?

For the MT

S=0 + (1/2)(.003695)(4.1^2)

S=.0310564 miles = 163.97 feet

For PDK

S=0 + (1/2)(.003876)(4.1^2)

S=.0325778 miles = 172.01 feet

For PDK LC

S=0 + (1/2)(.004065)(4.1^2)

S=.0341663 miles = 180.39 feet

Upon reaching 60mph in 4.1 seconds the PDK with Launch Control will have travelled 180 feet. The PDK car will have travelled 172 feet and be about 1/2 car length behind while the MT car will have travelled 164 feet and be trailing the LC car by slightly more than a full car length.

Not the 35 feet I referenced initially but not insignificant either for just a 4 second run.

Waxer

Well I can't challenge the math primarily because I don't understand it in the slightest...but assuming you can tell you went 8ft further from the seat of your pants in 4 seconds...again I impressed but again I doubt you could.

Formula used...common sense.

krysFly

GentlemanRacer

For what its worth, I watched a novice practice on the slaloms and hit cones everytime.

Just for the heck of it, i did the slalom and I could get to the end of the section at a much higher rate of speed and quicker without hitting any cones.

Just for fun we did a 0-140kph run on a stright on the track. He beat me everytime.

We drove the same cars 997.2 c4s, but mine MT and his pdk.

I had a bmw man/auto which I did street and autocross and eventually I always left in auto, because it was easier.

Given the choice I eventually chose easy, everytime.

That's why I prefer manual because I don't have the choice.

Now on top of having to better my own driving, I have to contend with novices with PDK. Hail the ski bunnies

ClintonM3

Wow, this thread is awesome. Is the most civilized thread about manual vs auto i've read, in a sorta weird entertaining way.

I say drive what you want. Drive what you can afford. Drive what you are able to. Drive what YOU think is fun.

If you still can't figure it out,.... get the MT. Only because you'll never have to justify about getting a MT on the forums.

Mike in CA

The math was just an exercise using basic formulas for acceleration and distance/acceleration. It wasn't intended to prove anything except to satisfy my own curiousity, correct the earlier claim I made about a 35' advantage to 60, and share the info with anyone who might be interested. From my long experience with MT's, though, the reason a PDK car "feels" faster is not so much the objective numbers but the more subjective feeling of instant response, quick shifts, ease of input, etc. It is faster and it feels faster. How important that is to anyone relative to the PDK/MT discussion is open to debate. But it does seem odd for people to try and dismiss one of PDK's advantages by saying, yeah, it's faster on paper but you can't feel it anyway.

sandwedge

Forget about 8ft, 4 seconds and 0.4 seconds. Looking at stark numbers is useless in this discussion (although Mike's math is impressive ). The margin may be slim but there's no disputing the difference in seat of the pants sensation during those 4 seconds between the MT and the PDK. Turns out it translates to real time in this case, slight as it may be. Have you driven both?

JamesT7

Hello Everyone

Nice math Mike. I like it. So I was thinking about the mention that is the PDK weaker as a manual driver on the track makes adjustments as he or she drives. Now I am not 100% sure about this so bear with me and please correct me if I am mistaken. As the PDK has duel clutches the next gear up or down has already been selected. So the slip we all have felt in manuals is not present in a PDK and there is less wear as the computer gets it right a lot more than us humans. And as there are no gaps in power or more preciously the gap is less than when shifting a manual. The acceleration is stronger and thus faster. So the PDK is going to be faster on the street and probably even more so on the track. As many have mentioned your shifting points can be adjusted as the PDK allows for significantly faster shifts and short loss of power and or momentium making for faster lap times.

I will say I was truly surprised that the PDK 911 was faster around a track than a manual and it is the first time this has been the case. As this discussion has proceeded it has become more and more apparent to me that for any of us to really understand the differences one has to drive both back to back and for a long period of time. May be there is somewhere to rent a 911 PDK for a weekend and really see how it is to drive in one's daily life.

When I asked the questions I have asked I was not ever trying to make it a debate as to which is better, more fun etc. Rather I wanted a good understanding from owners that have owned both and currently own a PDK to see how they like driving it now after owning it for a period of time. In my 2003 M3 I got it with SMG and it was fun and I liked it in the beginning but after a bit I just didn't use it and it stayed in auto most of the time. I like driving and performance driving so as I step back into a Porsche 911 again I want to have all the fun I remember of my previous driving 911s (all were manual) and possibly embrace new technology too. I truly love the time we are living in and seeing the advances.

Thanks to everyone commenting. Please keep writing your thoughts.

Cheers,

Mike in CA

I think you've got it James. I would only disagree with the first sentence (I know you're just referencing other's comments). For autox, at least, PDK responds incredibly quickly to the driver's demands and always seems to be in the right gear in the right situation. Walter Rohrl, Porsche's top test driver, posted identical times at the Nurburgring in PDK and manual equipped cars. Short of professional drivers at his level, PDK will be faster for the overwhelming majority of the rest of us.

997_rich

I've driven both in a 997 and I enjoy the MT more. Just a personal choice- drive whichever you like.

Regarding seat of the pants measurements- I always understood this to be the feel of how hard the car pulls in any given gear (instantaneous acceleration).. not so much the overall speed or distance traveled (or overall average accelation for a run). By that definiton, the PDK and MT should be the same. You'll be spending more time getting into gear on the MT but once you're in let's say second gear at 5k RPM it's going to be the same instantaneous accelation at that second in either PDK or MT. You lose the time in a drag race in a MT because you're taking the engine out of line with the drivetrain to shift and that's wasted time that you could have power going to the rear wheels.. during those times of course the seat of the pants measure will be better in the PDK.

Alan Smithee

So then PDK isn't faster.

What you are now comparing is our driving skills vs. Walter's.