With more hardware -- front axle/diff, cardan shaft -- there is always more to go wrong. If the front diff/viscous coupling "dies" a new front diff is thousands.

There are used ones available which can be had for less than new cost.

The AWD setup brings with it a more complex fuel tank and fuel supply system. The tank divides into two separate basins. These are not connected so to get fuel out of each basin there is a siphon jet.

In some cases a hose can fail and the car runs out of gas at around 1/2 tank. There is plenty of gas left just the non-functioning siphon jet can't remove it and supply the fuel to the engine.

Because of the split tank the fuel level is derived by the OBC and how the car is being driven. This appears to work ok actually. But if the fuel tank is low and one doesn't fill the tank up the added fuel may not register. I always fill the tank up when I fuel up the car so I have not ever experienced this.

As for performance enhancement I think it miminmal. The front diff is driven by a viscous coupling which relies upon a special fluid that when it gets hot (300F+) it becomes quite, well viscous, and torque is transfered to the front diff.

Porsche says anywhere from 5% to 40% with the 40% coming only when the car is going approx. 150mph.

When I bought my Turbo of course it came with the AWD system. If I knew then what I know now had there been a factory RWD only version of the Turbo I would have preferred that. (Well, there is the GT2 but for various reasons this wasn't a viable alternative.)

 

A major difference I've noted is the chrome "Carrera" logo on the back of a C4 vs. the black logo on the engine cover of the C2. To offset this I removed the black logo and put a chrome logo on my C2. Going for the rapper-Hummer look.

The answer to the implied question "which one is ideal / better / etc." seems self evident:
- Do you drive in snow or live in Seattle? If yes, C4(S) offers more utility
- Do you have a 2nd car or live in an area that has limited bad weather? If yes, C2's lighter weight & more classic handling characteristics might offer more fun.

I'm in a mountainous state with about 2-3 cold months/year when I'll let my C2 hibernate. For me the C2 is perfect. I don't really want to drive it with temps near 0F anyhow due to the scoring potential.

I've heard a rumor that you can disable the front wheels on the C4 for dyno tests by slightly pulling up the e-brake, fwiw

 

I can speak only from test drives. C2 feels agile and with less weight up front, really planted under your butt. I never drove on on the track, but boy did I want to. (This goes for all the RWD 911s I've driven over the years.)

My C4S is a blast to drive, but I do feel the added weight up front. Coming from BMW world, that in itself isn't bothersome, but there is something of that gotta-race-this-thing feeling that's lost. But I wanted a 911 that would take me across mountain roads in winter and C4S seemed the way to go for that. Schedule kept me from taking her out to the track this year. Just this past weekend was a PCA event at my second-favorite track (that I've driven on—HPR) and it would have been a perfect cap on the summer before switching to the winter tire set.

Not sure if this is helpful. Money aside, I'd love to have BOTH!

 

If I remember correctly the added weight of the AWD setup is give or take 118 pounds. Driving under normal conditions on a road - I can't imagine they're too different if at all. The biggest difference for normal use would be less frunk space up front. So, my opinion, is they're virtually the same for normal daily driving and to get whatever you want.

 

 

The AWD won't help you a bit if you get the rear wheels stuck. If you spin the rear wheels too long/much this just burns up the viscous coupling.

There are a number of YouTube videos of 996 C4 and Turbo owners hooning around in the snow. Some show the rear wheels spinning furiously while the front wheels/tires are stationary or nearly so. Hardly any torque is being transmitted to the axle just the viscous coupling being abused.

And pulling on the e-brake handle has no effect on the AWD feature. The coupling between the rear diff and the front diff is through a viscous coupling that is always active.

If one ever needs to dyno a C4/Turbo it must be done on a dyno that has the rear rollers driving the front rollers.

 

^ interesting, thanks for the clarification.

 

Glad to hear my picture helped you Tony.

 

I think C2 base is like 2,900 and a C4s is 3,200.... that's a huge difference in a car with only 320 HP....

I own a C2 and my best friend bought a C4s last month... I went for a ride in his car yesterday, back to back comparison after driving my car and the two cars are actually completely different feeling... they DO NOT drive like each other...I was shocked. Mine is a 2003 and he has a 2002

 

I ain't never seen Gnat cover his face in lemon juice.

The C2 has a "2" instead of a "4."

[Hey... is this post visible to you guys? I put lemon juice on my keyboard, so it might be invisible.]

 

I think you cracked the mystery of my hidden posts! I guess I need to lay off the lemonade.

 

What post...?

 

Did some more Dunning Kruger research, and found something of interest. Although it may not apply to Mr. Tiny Annoying Bug, I believe there is one forum member that we can all see described to a T:


Unfortunately, that member will be unable to recognize himself due to his Dunning Kruger affliction.

 

It's me, isn't it?!!! (sniffle sniffle). You didn't think my C2/C4 image was funny. (sniffle loudly) I'm so hurt, I'm going to curl up in a corner in a fetal position and suck my thumb! Oh the humanity!!!!!!!!!


shaaaa bam!

 

The mere fact you were able to recognize it was you, means it wasn't you.