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YOUR RESEARCHRWD vs the all-wheel drive C4S?
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Use c4
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Read evidence and context
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On the positive side I have used a C4 on an wet autocross circuit and it performed well.
Leading evidence: 'Use c4' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'best looking 996 ever produced' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Replace lanes' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Suspected cause
Everyone thinks that the 9964S is probably the best looking 996 ever produced.
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Suspected cause
I would suspect the turbo bumper is heavier as well.
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Suggestion
In the snow/ice the AWD helps, but the front can be a little more squirmy compared to FWD, especially changing lanes.
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Suggestion
You need to change the oil in the front transaxle but that's pretty infrequent and not a big deal.
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Suggestion
It had the capability of sending 0-100% of the power to the front wheels almost instantaneously without a delay from a viscous clutch - the 964 version multi-clutch plate system is what the 997 turbos have gone back to using with a couple changes thanks to technology advances.
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Suggestion
It had the capability of sending 0-100% of the power to the front wheels almost instantaneously without a delay from a viscous clutch - the 964 version multi-clutch plate system is what the 997 turbos have gone back to using with a couple changes thanks to technology advances.
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38 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
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I was looking at AutoTrader and other sites (I really need to stop torturing myself until I�m ready to buy a 996 later this year!) and saw several Carrera 4 996s for sale at quite reasonable prices. Some are even less expensive than similar condition and millage RWD versions. My initial thought was to stay away from a C4S since it has more components and therefore more that could go wrong with it. I also have fun driving RWD in the snow and wet and can�t see myself specifically looking for a C4S. Is there any additional maintenance that needs to be done with the all-wheel drive systems? Any known issues and how reliable are they? Is there a way to manually turn the all-wheel drive off? I couldn't seem to find this info in the books I have or searching threads.
You need to change the oil in the front transaxle but that's pretty infrequent and not a big deal. I've never really heard of many people having problems related to the 4wd system. I'm just about to hit 100k miles and haven't had any problems with it.
There is no way to turn off 4wd.
For me, the extra confidence in bad conditions is well worth it.
the only problem Ive heard is with the Turbo awd.... when people start modding their cars to like 600+ hp... the the awd become unreliable.... the viscous coupling just spins till the power lessen.
For the c4 or c4s.... its a simple setup that is designed for stability rather than an AWD function. You can still drift with the c4s and drive similar to a c2.... I would say the steering feedback is better on the c4 than a c2 since the steering is attached to the front wheels. The diff couples the power from 5%-55% (or something like that) so it is always on but the power delivery is based on rear wheel slippage..... no slippage means %90 of the power is to the rear wheels.
IIRC, the "percent of power to the front wheels" ratio varies between 5% and 40% on the C4/C4S, which means 95% to 60% of the power goes to the rear wheels.
However, I could be wrong because I did NOT stay at a Holiday Inn Express last night.
I haven't yet taken delivery of my Carrera 4S (a little more than a week to go)... so I can't give much commentary there. Is the AWD system there similar to the Cayenne's AWD system? I can tell you this - the Cayenne will gladly throw the rear end out on slippery streets, even with PSM active. It clearly favors the rear wheels. The fronts eventually kick in, but it is not instant response. I wouldn't call it an excellent winter vehicle, especially not with the 20" wheels...
The system cannot be turned off and from what I have read it is not particularly problematic. I'm personally not a big fan of the AWD system because of the parasitic hp loses, extra weight, and additional understeer the system delivers (plus I think it saps some of the RWD fun in these cars).
On the positive side I have used a C4 on an wet autocross circuit and it performed well.
From a looks standpoint, I think the C4S is the best looking (non turbo) 996. The wide hips and turbo front make for a sharp looking 996.
Good luck
Yeah, I think the only really problematic awd was the 964, what do they call it something like "NASA AWD" because of the tremendous complexity and costly repairs....
The thing I considered was the additional weight, but having a bit more weight up front on a rear-engine car is not a bad thing....
I can attest to the fact that the AWD system does not get in the way of "rotating" the car. I have a nice 110 degree right hand turn that I love to take with a little speed (if there is no one else around). A little throttle in the turn and the car just rotates. I love it!
The 4WD of the 996 and 997.1 models is very simplistic. It's a viscous clutch that is pretty simple, and thus a LOT less expensive to maintain. To be perfectly frank, the BIGGEST selling point for the 9964S is the LOOK. Everyone thinks that the 9964S is probably the best looking 996 ever produced. This is what keeps its prices higher.
It hasn't been until now, on the 997.2 AWD cars, that they have entirely redesigned the AWD system away from the viscous clutch and more like the 959 and the early 964s. When Porsche discovered how much trouble and expense was involved in maintaining the 964 Carrera 4s, they went back to simplicity itself, with the viscous clutch (like in the Vanagon Synchro).
on the track, I have no issues with AWD whatsoever. in fact, on a wet skidpad at Laguna, I had no problems causing fuel starvation with the *** end hanging out and a rooster tail.
+1 on the looks. I think the C4S is the best looking 996 of all. I chose a C2 over the C4S because I wanted low mass for the track.
Yup. On the track, I recently followed a friend and watched him rotate his C4S 180 degrees.
No, no... the 964 AWD system is not any more problematic than the rest of the systems - it was too expensive to manufacture at a time when Porsche was not doing well. It works extremely well, is extremely reliable, and doesn't require any further repairs over the cheaper viscous systems. It had the capability of sending 0-100% of the power to the front wheels almost instantaneously without a delay from a viscous clutch - the 964 version multi-clutch plate system is what the 997 turbos have gone back to using with a couple changes thanks to technology advances.
Not that this matters for this discussion, but no need for further 964 rumors to spread!
The nature of the viscous slip AWD means that there is a slight delay before power is transferred to the front. So it handles more or less like a RWD. It does not handle like the other AWD systems that sends even power to all 4 wheels at once. In the snow/ice the AWD helps, but the front can be a little more squirmy compared to FWD, especially changing lanes.
The steering on the AWD feels a little heavier because the front tires are being driven. The AWD feels a little more stable under power coming out of corners when conditions are slippery. A C4S is about 275 lbs. heavier than the C2.
For the Top Gear comparo:
http://coochas.com/porsche/Resources...Gear121105.mp4
the weight differential is not only due to the AWD system, but wider tires and heavier wheels, WB vs NB, and brake system being larger among other things. I would suspect the turbo bumper is heavier as well.
My thought process a year ago was that I'm not going to take the car on the track that much and I live in the northeast. Even when I take it on the track, is it really "that" much slower than a C2? Most of the time it should be driving like a RWD with a bit of pull from the front (5%-95%). I really never get to the point where the viscous coupling will have transferred 30% to the front, which is supposedly at about 155 mph. The only time it exceeds 30% and gos up to almost 40% is when the rear weals are spinning.
So I couldn't go wrong with a C4S, plus I absolutely love the looks of a C4S!
I think you are misunderstanding how the coupling operates. It is not speed dependent, rather it is slip dependent. The more slip the rears experience the more power the coupling transfers to the front wheels.
Some info here
http://www.awd.ee/viscous.html
996 vs 997 system
http://www.porsche.com/microsite/tec...PMT911TurboAll
Ray,
Thanks for the info. I was under the impression from the "Essential Companion" that it had a combination of both, slip would take it up to 40% and normal driving would take it up to 30% (at 155mph/250kph).
Thanks,
Eric
Because the grass is always greener...
While not an absolute, in the 6 years of being active on the Rennlist 964 forum, I know of just 3 owners that have done the conversion for various reasons, not due to problems. Joel Reiser's article in Panorama seemed to scare a lot of people... just like the internet does with 996 engine failures.
At the track, the C2 "would" be faster with the correct driver. With the average driver, the C4S will instill confidence much more than the C2 that the C4S will "seem" faster.
Also, we're not racing for medals on DE's. So it doesn't matter in the end. What matters is how much fun and education the owner experiences.
It's similar to people always saying PS2 is much better than, say, Conti SportContact 2 simply because it's stickier when it's the same people who can't even reach the PS2's limits, especially on the street.
Excellence magazine had an article in the 12/02 issue on the 9964S comparing it to the C2 and said the it was about 4 sec faster around Nurburgring.
"[T]he Carrera 4S lapped the Nurburgring in less time than the faster-accelerating and more slippery standard Carrera could. Admittedly, the difference with the factory's test driver behind the wheel was just over four seconds over 14 miles, but there's more to the story. The C4S instills so much more confidence that we're certain the C4S would handily show its taillights to lesser Carreras in the hands of an average driver down the same stretch of road or track."
seems like this comes up every few months! Compared to a factory Porsche test driver, we are all below average drivers.
Come on folks, just accept the facts that the C4S is faster for 90% of drivers out there and be done with it!
Based on a "ring time"? Surely you realize that two different drivers going around the ring on two different days (probably with two different tires) is not a super strong basis for camparison.
I'd submit that on a dry track the C2 would generally be the faster choice as it's carrying far less weight and has less parasitic driveline losses. The bigger brakes on the C4S would only be valuable if the C2 had problems with brake fade with it's smaller brakes which it does not. The C4S does have room for bigger rear tires, but I've seen C2's at the track with 315's in the rear and I believe anything bigger would be total overkill.
I'll grant you the C4S is nicer looking and would be superior in inclement conditions, but even with an open diff a C2 has no real problem putting down a somewhat meager 300-320 hp on a dry track (meager compared to what a GT3 puts down through basically the same chassis). If the 996 GT3 has no problem putting over 380 hp down on the track, where is the advantage for AWD in the same chassis with 60-80hp less and a 275lb weight penalty?
Bottom line at the track power to weight ratio means a lot.
Having just gotten into a 2003 C4S, all I can say, it the best P-car I have ever driven (30 yr PCA member). It is even better than my 1972S and 944 4Turbo (modified). it is more stable than every thing I have ever driven. and it is so easy to drive fast, it is just wonderful.
My next P-car will be a C4s, and the next, a C4S......
roy
