Love hate relationship with the C4

[afterburn 549]

(10101010) -_--_101010(()*&^%%$$10101010

[sammyg2]

[masraum]

Originally Posted by afterburn 549

Will someone explain what the removal of the front wheel drive is all about?
Why?
Did Porsche do it wrong?
What is the story ?

I assume it's for weight and/or dynamics.

[pavulon]

Complexity, cost and weight reductions

[Tervuren]

I'm not sure I understand what we're talking about.

Did Porsche discontinue the C4?

Personally when I read C4 I think of a Corvette.

I guess I'm not a 911 guy.

[Racerbvd]

Originally Posted by afterburn 549

Not sure when they started making them.
I have read various times about the 4wd deletion.
Just courious.

1989 is when Porsche released the 964 C4. The 993 version was much improved.

[Tervuren]

I believe it started with the 964, which is also when Carrera became "standard" instead of special.

1989? Maybe 1990.

As far as I know it has been available from the 964 to present.

The 911 Turbo became AWD as standard, perhaps with the 964 as well.

[speeder]

They started in 1989 w the then new 964 or Carrera 4. The AWD system has gone through evolutionary changes since then w the subsequent 993, 996, 997 and 991. They have probably refined it further for the new 992.

It's basically a torsion split system, (do I remember that term right?), road-going AWD like what is found on Audis and many other cars now. It's geared towards dry road performance w torque biased quite a bit towards the rear wheels on 911s but the split can change if traction needs change, such as on snow or ice. All turbo 911s have been AWD since the 993tt, w the exception of the GT2 which is RWD.

I think that Porsche absolutely got it right w this system but I and many other enthusiasts in warm locations greatly prefer 2wd 911s or C2s due to their lighter weight and more sporty characteristics.The difference is not huge but it's there and when talking about cars that are fine instruments, every degree definitely counts.

I've heard of people removing the front driveshaft from turbo cars starting w the 996tt to save a couple pounds but unless you get rid of the transfer case and exchange the front hubs for 2wd items, the weight savings would not be significant in a car of that weight, IMO.

Porsche made a commitment to AWD in their highest performance regular production cars back in the '80s and the 959 was the test bed on wheels for it as well as several other advanced systems at the time. The 959 debuted in 1986 and AWD showed up on the production 964 3 years later in the 1989 model Carrera 4.

[Nickshu]

People remove the FWD from C4's either due to mechanical problems that they don't want to fix or to improve the ability to throttle steer the car during track use.

Unless you pull everything out the weight reduction is likely minimal just by disconnecting the drive shaft and half shafts.

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[plumb4u2]

Originally Posted by Tervuren

I believe it started with the 964, which is also when Carrera became "standard" instead of special.

1989? Maybe 1990.

As far as I know it has been available from the 964 to present.

The 911 Turbo became AWD as standard, perhaps with the 964 as well.

Carrera became standard in 84 with the release of the 3.2

[masraum]

Originally Posted by Tervuren

I believe it started with the 964, which is also when Carrera became "standard" instead of special.

Nope, all of the 3.2L cars ('84-89) were badged as "Carrera".

[unclebilly]

Originally Posted by Racerbvd

1989 is when Porsche released the 964 C4. The 993 version was much improved.

Actually, the 964 system was superior to the 993 system. The 993 system was dumbed down because the 964 system was 'too complicated' (read expensive).

My 964 C4 was awesome. I drive it through a terrible snow storm in Colorado when I first bought it.

At the track, it was heavy but laid down some pretty great lap times for a stock car on Pirelli Pero Nero all seasons.

[brainz01]

Porsche's AWD systems work pretty well. Benefits are more traction at the expense of an extra ~200lbs of parts. As stated above, its mostly the added weight that you notice (especially on the later models, eg 997s and newer, as the computers do a good job invoking the front wheels only wheen needed). The steering is a little more numb and the car feels heavier.(because it is).

I believe you can convert from AWD to RWD by removing the front driveshaft, differential and half shafts on the 964, 993, and 996 models. Each model likely has a few other model-specific changes to make it work, but the conversions are well documented. Unfortunately, on the 997s and later, PASM (stability management) is integrated into the AWD system, so removal of the front diff (the heavy part) causes computer errors. I think a few have done a work around, but it's not widely or done.

Fun fact: There is "drift hack" on the 997s, where you pull the e-brake just enough to bring on the parking brake light. This signals the computer that you're possibly trying to slide the back end and will disengage the front wheels allowing the driver to do sweet smoky donuts or slides if that's your thing....

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[911boost]

I cannot really feel the AWD system on my 996TT.....

[Bill Verburg]

Not counting niche vehicles like 959, Porsche has used 2 basically different AWD systems on versions of the 911 since 1989.

the 911s built from 1989 to 1994 aka 964 used a very complicated version. In this version the trans main shaft is hollow w/ the front drive running concentrically w/ the rear drive output. The rear is the inner shaft and the outer is the front drive.


the front drive connects to a computer controlled clutch pack in the trans nose cone. There are also lateral and longitudinal accelerometers that feed info to the computer to help it decide how much lock to impose. The front drive shaft connects to a front diff, the rear to the usual CWP




The 964 has been described more as a snow oriented system than as a performance oriented system as the the later awd systems are.

The 993 up use a much simpler and lighter AWD setup. They take a regular g50 and
connected the trans main shaft to a viscous coupler in the nose of the trans, the viscous coupler is a purely mechanical system that adjust torque flow though to the front. The 964 system can only be removed after major surgery, The brake hydraulics are shared w/ the awd, and the trans main shaft would need to be welded up. The 993 on system can be unbolted in it's entirety. Yes the reason is for better track performance by being able to steer the car w/ the throttle.

993 viscous coupler


removed



modified and sealed front cover

[Shaun @ Tru6]

My understanding is all 1989 C4s were guards red. Heavy, dog of a car IMHO.

[HardDrive]

[unclebilly]

Here is my old 90 C4 Targa

[Racerbvd]

I had one, one rainy days, that car was great, and as others have said, very fast on the track, but boring because the car saved you from mistakes. He is a picture from the C4 introduction party at Brumos Porsche.


Here is the old 964 on track with a friend/student.

[speeder]

Originally Posted by Shaun @ Tru6

My understanding is all 1989 C4s were guards red. Heavy, dog of a car IMHO.

Not true. I had an '89 C4 that was Linen metallic w a Linen interior. And it was an early production car. The launch cars were all red, though.