30 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHwhat are real world objective differences between a C4 and C2?
Leading reported evidence
Replace front diff unit
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
I recently replaced my front diff unit with one from a low mile used unit (from a later model 996 - '05 I believe).
what are real world objective differences between a C4 and C2?
Read full discussion summary
Leading evidence: 'Replace front diff unit' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'trying' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Replace front diff unit' (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.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
Though we do not get a lot of snow in the city I use snow tires in the winter just for the added traction in sub 40 degree wet weather we commonly have.
what are real world objective differences between a C4 and C2?
trying
Suggestion or failed attempt
No successful repair reported for this finding.
0
Identified cause
1
Suspected cause
0
Reported fixes
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
It was making some nasty noises when pushed (I suspect trying to engage) and the front wheels didn't move at all while spiunning the rears or the opposite front(while jacked up).
what are real world objective differences between a C4 and C2?
wider hips
Suggestion or failed attempt
No successful repair reported for this finding.
0
Identified cause
1
Suspected cause
0
Reported fixes
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
what are real world objective differences between a C4 and C2?
Replace front suspension
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
I forgot that along with adding the Front diff porsche did need to change the front suspension.
what are real world objective differences between a C4 and C2?
Reported and suspected causes (2)
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
trying
No successful repair reported for this finding.
0
Identified cause
1
Suspected cause
0
Reported fixes
Read evidence and context
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
It was making some nasty noises when pushed (I suspect trying to engage) and the front wheels didn't move at all while spiunning the rears or the opposite front(while jacked up).
what are real world objective differences between a C4 and C2?
Coverage and how to read this overview
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
30 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
1 acknowledgements have no verified action link; they do not establish a repair result.
Outcome without a verified action link
But Porsche claimed there was no difference in "feel".
Big difference is Two More wheels pulling... to some degree, based on inputs from sensors. Totally redesigned Frunk with collapsed Spare under the floor is most noticeable to the user. Tip Buttons on the steering wheel. The US 2000 C4 had the Faux Suede Headliner. "Carrera 4" Door sill plates. Other than that and all the hardware under the car - I can not think of other inside the car changes. From the exterior the Badge on the Engine lid and "Platinum" Calipers are the only changes. Tough mine is a an early 2000 - January production C4 - and it has Silver Porsche Crest on the Hood and the Steering Wheel, rather that Gold. I have only seen this on another early build C4 MY 2000. And oddly the Silver Hood Badge is a Porsche 993 part number?
Oh, and I forgot to mention, that according road test by
Mario Andretti, in his opinion,
The C4 was - the Best Handling Sports Car in 1999 ! :-)
C2 vs C4, VERY different cars!
From all the posts I've read over the years, the C2 is going to be cheaper to maintain.
The C4 will drive better in twisties, but it's heavier and isn't as "nimble".
If I lived up north in the snow, I'd get a C4 and drive it all year.
That's my .02.
Nothing to add but I’ve seen more C4’s in the Naples area in the past couple years than everywhere else combined. Several of them running around. Also, more 996’s popping up this winter than I saw last year.
TC
This table shows many different data points from different sources.
Looks a bit variable. Seems to show the C4 getting more G's on skid pads. Better than the C4S too.
http://www.weissach.net/996-997_RoadTestSummary.html
Driven both, the extra weight makes the car feel more planted. I drove a few c2�s and C4�s and recall the ride on the highway with the c4 felt much more reassuring on the road. The C2 felt light in the front. I felt the 4 felt more like a 100k car, more solid.
Some people like the lightness better. You really need to drive each to make your own decision.
The front differential of a 996 C4 is relatively simple and does not weigh much. Many have removed them and can testify. Still, people often feel that the ride is more planted. is that the result of the extra 80 pounds? Or is it differences in suspension?
The C4 doesn�t have wider hips - that would be the C4S... Most of the differences have been mentioned, but one I didn�t see was chassis stiffness... the C4 is noticeably stiffer (this is well documented) which leads to a different driving feel...
yes, yes, this is correct. remember we are talking C4 not C4S.
Few people mention it but the C4 chassis is the same as the GT3 chassis. That is to say that the C4 uses the GT3 chassis or the GT3 uses the C4 chassis. either way, it is stiffer. Not sure how much weight is added as a result of just the changes in chassis when compared to the C2 but feel like that is a worthwhile benefit.
C4, C4S, Turbo use the same chassis. Is the GT3 AWD? If so probably same chassis, but not sure... the info is out there, I just don�t remember off hand...
GT3 uses the C4 stiffened chassis, but is RWD only.
I've worked on both C2 and C4, but only driven a few C2s.
If you're installing struts/shocks/coilovers, it's easier on a C2 than a C4.
That doesn't make the C4 really difficult, just a little more than a C2.
If I were going to daily mine where I might encounter slick conditions, I would prefer a C4.
I daily mine down here were we have Early Summer, Summer, late Summer, Fall, and sometimes about 4 days of winter...I'll stick with my C2.
So, how does the gt3 feel compared to C4? Not talking horsepower here, talking handling. Alternatively how does a GT3 drive if you compare to a less stiff C2 chassis in aggressive situations? The C2 guys appreciate the lighter weight but it isn't much vs the C4, (C4S is a different story.) Drivers report a more solid feeling in the C4. Is that because of the AWD or the stiffened chassis? or the additional 80 lbs over the front axle?
In other words, how much does active drive to the front wheels affect balance and handling in a C4 in comparison to RWD (GT3) only since they share the same chassis? Apparently, the reality is that the torque sent to the front is minimal.
"
In other words, how much does active drive to the front wheels affect balance and handling in a C4 in comparison to RWD (GT3) only since they share the same chassis? Apparently, the reality is that the torque sent to the front is minimal."
I believe the maximum power sent to the front wheels at any given time via the 996 AWD system is 40% (this would be at high speed driving situations) with 60% going to the rear wheels. This is not the case at low speeds, and it's a strictly mechanical system (viscous coupler between drive shaft and front axles). FWIW, the awd is not particularly useful in deep snow - especially from a standstill - once moving it's definitely helpful, but not like modern type electronically controlled AWD systems. the 996 is a sports car and it's awd system is tailored to sports car driving situations... these are not SUV's...
is it true that the C4 was quicker around Nurburgring than a C2?
How does that happen with a heavier car that is not as a sporty as the commonly believed C2? Is it the all-wheel drive or is the extra stiffness the difference?
^^^ Not sure where these #'s are from, but 5 100ths of a second difference is easily chalked up to a million different variables and can't really be considered a difference at all. The bottom line is that the awd system in the 996 C4/Turbo/C4S is really geared toward high speed handling characteristics (in wet or slippery conditions as well). Everything else being equal, I think it's fair to say a stock C2 would beat a stock C4 in a straight line race, due to the weight differential and the parasitic power loss to the front wheels/axles - no doubt. Around a track such as "the ring" I would think the C4 would have a clear advantage...
How do you feel about posts that indicated the viscous coupler becomes less effective with time and the AWD affect is diminished, negligible? I hadn't heard that before but read it recently. Like many things, you can't believe everything you see on the interwebs.
^^^Absolutely true! I recently replaced my front diff unit with one from a low mile used unit (from a later model 996 - '05 I believe). It was making some nasty noises when pushed (I suspect trying to engage) and the front wheels didn't move at all while spiunning the rears or the opposite front(while jacked up). I can tell you that I can certainly feel and hear the difference with the new diff. I'm not sure exactly what fails, but I'd surmise that it's the silicone "fluid" in the VC. Perhaps once the fluid fails the plates in the coupler also wear or break so the replacement of the fluid won't fix the coupler?... Whatever the reason(s), it seems re-built/re-conditioned units are not available, and a new viscous coupler sells for around $1300 - ouch! It surprising to me that there are no aftermarket units or re-build/re-condition services available for more reasonable prices - it seems by now that there would be a fairly robust market... Who knows?
There is only 2-5% going to the front. The only time is goes to 40% is while the rear slip enough to heat up the fluid and then it hit 40% until the rears stop slipping and then power is restored back to the rear again. It is a weird feeling losing 60% of engine power all of a sudden and transition back is hardly felt. I don't think it really helps in every day driving it just is a fantastic life saver when the rears do slip.
I forgot that along with adding the Front diff porsche did need to change the front suspension. They moved the Struts rearward to accommodate the front axles. But Porsche claimed there was no difference in "feel". (comment from Excellence May 1999) And the Gas tank is re-designed to make room for the front diff & drive shaft but about the same size. And at least for the early builds there was standard PSM, and that required the electronic throttle. Later C2's had optional PSM. And I did not mention that unless and owner specified a optional wheel style, the base 17 wheels were a uniques 5 spoke design to the C4. And just to be clear the C4 996 4 wheel drive system was different from the 993 version. The viscous coupling was moved to the front diff to allow for the first time a Tiptronic in a C4. The Drive shaft was different as well. A light weight shaft (no Tube) saving nine pounds.
Though we do not get a lot of snow in the city I use snow tires in the winter just for the added traction in sub 40 degree wet weather we commonly have. Fo me the C4 is the perfect Carrera.
It's worth repeating that the difference between the 2 is succinctly stated in post #3. 128# added to a 3000# car is an extra 4%. 100# here, 100# there, and today we've got 911s at 3500# that are 'light'. Having owned a C2 996 since new, the differences noted between the 2 at that time were significant. Extra cost was a factor as well.
