Opinions on revised AWD System?
05-28-2011, 12:29 AM
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Opinions on revised AWD System?
A friend is ready to buy a Porsche again after being an NSX owner for several years. He asks my opinion on whether he should wait until the prices come down on 2010 C4S enough that he can afford one, because he thinks "the revised AWD system" is worth the wait.
He expects at least a three-year wait with that goal in mind. I certainly would suggest someone do all they can to get into a 997.2 for all the improvements collectively, but I must admit to being stumped on whether or not to let it all hinge on the AWD changes.
What were they? And how do the C4S owners feel about the changes? Are they as important as my friend thinks they are from listening to various other sources?
Up front, I'll say that my initial reaction is that now is a good time to be selling a well-used exotic like his NSX. I think he should make the jump to a Porsche and enjoy it. He can always trade up to a 2010 after a few years. That's my intuition, but I really want to hear from those of you who keep track of C4S design issues and benefits.
Gary
He expects at least a three-year wait with that goal in mind. I certainly would suggest someone do all they can to get into a 997.2 for all the improvements collectively, but I must admit to being stumped on whether or not to let it all hinge on the AWD changes.
What were they? And how do the C4S owners feel about the changes? Are they as important as my friend thinks they are from listening to various other sources?
Up front, I'll say that my initial reaction is that now is a good time to be selling a well-used exotic like his NSX. I think he should make the jump to a Porsche and enjoy it. He can always trade up to a 2010 after a few years. That's my intuition, but I really want to hear from those of you who keep track of C4S design issues and benefits.
Gary
05-28-2011, 01:25 AM
#2
Poseur
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I believe that the work involved by Porsche with the revised electronically controlled AWD system (introduced on the 997 Turbo, and then found on the 997.s AWD cars is reliable and a far better piece of engineering than the older viscous clutch design.
History. Porsche designed a very sophisticated AWD with the introduction of the Carrera 4 (964) in mid 1989. It was based upon the lessons learned with the 959 supercar. Unfortunately, in a standard production car, the sophistication was simply too complex. The 964's AWD system was quickly abandoned when the 993 Turbo and 993 Carrera 4 was introduced. Porsche realized they needed AWD but elected to keep things simple--and much cheaper to maintain. That viscous clutch approach to AWD stayed around a long time--through the 993 production, and into the 996. When the 997 Turbo finally came out in 06 they changed it because their computer controllers were much more reliable. That is the design in the 997.2 4s. It appeared in MY09, at the same time PDK came out. The differences between an 08 4 and an 09 4 are substantial. So far, the reliability of this new design seems to be effective and holding up. (I'm pretty such the 997.2 AWD cars arrived in MY09--not MY10, but I could have forgotten).
I would certainly wait a bit longer for prices to depress on these better cars. They are substantially different, with the newer AWD system, PDK availability, and of course the DI engines. All of these mechanical changes add up to a very revised car. Of course, there are the internal cockpit changes, too, like the revised PCM. I believe in time you will see a big price delta between the MY08 and MY09 cars--particularly for the 4s.
History. Porsche designed a very sophisticated AWD with the introduction of the Carrera 4 (964) in mid 1989. It was based upon the lessons learned with the 959 supercar. Unfortunately, in a standard production car, the sophistication was simply too complex. The 964's AWD system was quickly abandoned when the 993 Turbo and 993 Carrera 4 was introduced. Porsche realized they needed AWD but elected to keep things simple--and much cheaper to maintain. That viscous clutch approach to AWD stayed around a long time--through the 993 production, and into the 996. When the 997 Turbo finally came out in 06 they changed it because their computer controllers were much more reliable. That is the design in the 997.2 4s. It appeared in MY09, at the same time PDK came out. The differences between an 08 4 and an 09 4 are substantial. So far, the reliability of this new design seems to be effective and holding up. (I'm pretty such the 997.2 AWD cars arrived in MY09--not MY10, but I could have forgotten).
I would certainly wait a bit longer for prices to depress on these better cars. They are substantially different, with the newer AWD system, PDK availability, and of course the DI engines. All of these mechanical changes add up to a very revised car. Of course, there are the internal cockpit changes, too, like the revised PCM. I believe in time you will see a big price delta between the MY08 and MY09 cars--particularly for the 4s.
05-28-2011, 08:09 AM
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Gary,
As Dan mentioned, the "revised AWD system" was introduced in 2009, so let your friend know that. An '09 car will be $7K to $9K less expensive (notice I didn't say cheaper).
As Dan mentioned, the "revised AWD system" was introduced in 2009, so let your friend know that. An '09 car will be $7K to $9K less expensive (notice I didn't say cheaper).
05-28-2011, 03:13 PM
#4
Drifting
I believe that the work involved by Porsche with the revised electronically controlled AWD system (introduced on the 997 Turbo, and then found on the 997.s AWD cars is reliable and a far better piece of engineering than the older viscous clutch design.
History. Porsche designed a very sophisticated AWD with the introduction of the Carrera 4 (964) in mid 1989. It was based upon the lessons learned with the 959 supercar. Unfortunately, in a standard production car, the sophistication was simply too complex. The 964's AWD system was quickly abandoned when the 993 Turbo and 993 Carrera 4 was introduced. Porsche realized they needed AWD but elected to keep things simple--and much cheaper to maintain. That viscous clutch approach to AWD stayed around a long time--through the 993 production, and into the 996. When the 997 Turbo finally came out in 06 they changed it because their computer controllers were much more reliable. That is the design in the 997.2 4s. It appeared in MY09, at the same time PDK came out. The differences between an 08 4 and an 09 4 are substantial. So far, the reliability of this new design seems to be effective and holding up. (I'm pretty such the 997.2 AWD cars arrived in MY09--not MY10, but I could have forgotten).
I would certainly wait a bit longer for prices to depress on these better cars. They are substantially different, with the newer AWD system, PDK availability, and of course the DI engines. All of these mechanical changes add up to a very revised car. Of course, there are the internal cockpit changes, too, like the revised PCM. I believe in time you will see a big price delta between the MY08 and MY09 cars--particularly for the 4s.
History. Porsche designed a very sophisticated AWD with the introduction of the Carrera 4 (964) in mid 1989. It was based upon the lessons learned with the 959 supercar. Unfortunately, in a standard production car, the sophistication was simply too complex. The 964's AWD system was quickly abandoned when the 993 Turbo and 993 Carrera 4 was introduced. Porsche realized they needed AWD but elected to keep things simple--and much cheaper to maintain. That viscous clutch approach to AWD stayed around a long time--through the 993 production, and into the 996. When the 997 Turbo finally came out in 06 they changed it because their computer controllers were much more reliable. That is the design in the 997.2 4s. It appeared in MY09, at the same time PDK came out. The differences between an 08 4 and an 09 4 are substantial. So far, the reliability of this new design seems to be effective and holding up. (I'm pretty such the 997.2 AWD cars arrived in MY09--not MY10, but I could have forgotten).
I would certainly wait a bit longer for prices to depress on these better cars. They are substantially different, with the newer AWD system, PDK availability, and of course the DI engines. All of these mechanical changes add up to a very revised car. Of course, there are the internal cockpit changes, too, like the revised PCM. I believe in time you will see a big price delta between the MY08 and MY09 cars--particularly for the 4s.
But I wouldn't buy one of the new DI engines until the intake valve "sludging" issue is resolved. I suspect that "resolution" will involve adding a throttle body fuel injector or two, but only to be used at idle or cruise.
05-28-2011, 07:53 PM
#6
Nordschleife Master
Following up on Dan's post:
The old 996/997.1 viscous coupler makes the front axle on-traction all the time. I had a 996 C4 and always felt front traction on, even if only 5 or 10%.
The 997.2 AWD couples the front axle via an E&M controlled multi-plate clutch. It can be totally decoupled Nd most of the time is. I am sure that from a functionality POV it must work very well. I suspect though that it is more binary in nature, i.e., off and progressively on; at least that is the feeling I have when autoxing the 997.2 4S, which I have done extensively.
If one wants 4WD for its added traction the .2 AWD is probably superior, but with a somewhat non-linear tracking feeling.
The old 996/997.1 viscous coupler makes the front axle on-traction all the time. I had a 996 C4 and always felt front traction on, even if only 5 or 10%.
The 997.2 AWD couples the front axle via an E&M controlled multi-plate clutch. It can be totally decoupled Nd most of the time is. I am sure that from a functionality POV it must work very well. I suspect though that it is more binary in nature, i.e., off and progressively on; at least that is the feeling I have when autoxing the 997.2 4S, which I have done extensively.
If one wants 4WD for its added traction the .2 AWD is probably superior, but with a somewhat non-linear tracking feeling.
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05-29-2011, 01:09 AM
#9
Drifting
Following up on Dan's post:
The old 996/997.1 viscous coupler makes the front axle on-traction all the time. I had a 996 C4 and always felt front traction on, even if only 5 or 10%.
The 997.2 AWD couples the front axle via an E&M controlled multi-plate clutch. It can be totally decoupled Nd most of the time is. I am sure that from a functionality POV it must work very well. I suspect though that it is more binary in nature, i.e., off and progressively on; at least that is the feeling I have when autoxing the 997.2 4S, which I have done extensively.
If one wants 4WD for its added traction the .2 AWD is probably superior, but with a somewhat non-linear tracking feeling.
The old 996/997.1 viscous coupler makes the front axle on-traction all the time. I had a 996 C4 and always felt front traction on, even if only 5 or 10%.
The 997.2 AWD couples the front axle via an E&M controlled multi-plate clutch. It can be totally decoupled Nd most of the time is. I am sure that from a functionality POV it must work very well. I suspect though that it is more binary in nature, i.e., off and progressively on; at least that is the feeling I have when autoxing the 997.2 4S, which I have done extensively.
If one wants 4WD for its added traction the .2 AWD is probably superior, but with a somewhat non-linear tracking feeling.
Virtually no front torque coupling except under acceleration.
The best of both "worlds", RWD "only" and AWD "as needed".
05-29-2011, 02:49 AM
#10
Nordschleife Master
No, it is my understanding that the coupling factor is modulated, moderated, via PWM dutycycle changes. HARD, low speed acceleration, straight ahead acceleration and the system is 50/50. Start cranking in some turning angle with the stearing wheel and the coupling level will be reduced accordingly.
Virtually no front torque coupling except under acceleration.
The best of both "worlds", RWD "only" and AWD "as needed".
Virtually no front torque coupling except under acceleration.
The best of both "worlds", RWD "only" and AWD "as needed".
05-29-2011, 04:10 AM
#11
Rennlist Member
I LOVE IT that people who have commented here do NOT own either a .1 or .2 C4S and are offering expert opinion based on what they read on paper!
I own a 997.1 C4S and have driven .2 C4S in Nurburgring... .2 AWD actually engages the front A LOT MORE than .1 (contrary to what's stated here)... it's definitely a more advanced AWD system and while I didnt get a chance to drive it in rain/snow, it should do better there.
However, the newer AWD is definitely heavier, and has changed the steering feel completely and it drove a lot more like my Audi than a Porsche 911. It did engage the front a lot more while ur slipping a bit in corners and it even understeered a bit more in my test.
So, overall I'd actually woudln't upgrade my C4S to .2 for its AWD as I LOVE how .1 feels and .2 was quite a bit more boring. If the purpose of buying the AWD system is to primarily drive the car in snow/rain conditions and the buyer is not much into tracking and how the car feels its definitely the better choice. However, for a dual purpse 911, with more feel of RWD the 997.1 AWD is actually superior IMO.
PS. I believe the AWD system in 991 will be revised, they had to change the way it distributed Torque in Turbo S and that car has had much better reviews than regular Turbo (which shares the same C4S .2 AWD).
I own a 997.1 C4S and have driven .2 C4S in Nurburgring... .2 AWD actually engages the front A LOT MORE than .1 (contrary to what's stated here)... it's definitely a more advanced AWD system and while I didnt get a chance to drive it in rain/snow, it should do better there.
However, the newer AWD is definitely heavier, and has changed the steering feel completely and it drove a lot more like my Audi than a Porsche 911. It did engage the front a lot more while ur slipping a bit in corners and it even understeered a bit more in my test.
So, overall I'd actually woudln't upgrade my C4S to .2 for its AWD as I LOVE how .1 feels and .2 was quite a bit more boring. If the purpose of buying the AWD system is to primarily drive the car in snow/rain conditions and the buyer is not much into tracking and how the car feels its definitely the better choice. However, for a dual purpse 911, with more feel of RWD the 997.1 AWD is actually superior IMO.
PS. I believe the AWD system in 991 will be revised, they had to change the way it distributed Torque in Turbo S and that car has had much better reviews than regular Turbo (which shares the same C4S .2 AWD).
05-29-2011, 02:34 PM
#14
Drifting
Yes, it is primarily RWD other than during acceleration when a level of front drive torque is "dialed" in according to the level of acceleration. The level of coupling becomes lower and lower, even under acceelration, as a function of lateral forces "applied" at the front.
And yes, exiting the turn, accelerating out of a turn, stearing wheel returning to "neutral", and the appropriate level of front drive torque will be dialed in.
There is NO substitute for book-learning.
But, clearly, a combination of both is more ideal.
05-29-2011, 02:50 PM
#15
I have not driven the .2 AWD so I can't comment if it's better or worst. I love the .1 AWD, it does not feel at all like an AWD cars that I've own and driven. It feels very much like a RWD, you feel the push rather than the pull. If you did not tell someone what it is, they will most likely tell you it's a RWD car when they are driving it. I don't know if the .2 is that much better to pay for the premium, however the upgraded PCM, DI engine and other things might be worth getting the .2.