LSD Question

Does the 996 C4S has LSD? 40th Ann 996 has a 22% lock LSD. What kind of LSD is used on the 40th Ann, GT3, '99 996? Can you retrofit it to a 02 Carrera, w/o buying an expensive new differential?

The 996 C4 doesn't have LSD. The 40th Anniversary car is the first PSM equipped car with an LSD. The asymetric lockup in teh GT3 is more radical than the 40th Anniversary (60/40 vs. ??). No idea if there's a factory retrofit but I've heard Porsche considers transmissions an exchange service item. Try checking with Guard Transmission as they'd probably be the best source for transmission mods.

I don't think any of the AWD cars in the Porsche lineup have LSD nor is it nearly as helpful with AWD

As I understand it: - AWD 996's have a viscous-coupling center differential (AWD) with Automatic Brake DIfferentails (ABD- and electronic differential) on front and rear axles that are still present even if PSM is off. - C2 has only ABD's, with PSM. - 40th Anniv has a rear Limited Slip Differential Lock with PSM. - GT3 and GT2 have Limited Slip Differential Lock's, the GT2's being asymetrical (no PSM).

As I understand it, Porsche built a small run of "Lux" cars for the 99MY and fitted them with white lights, special leather interiors, tint banded screens, LSDs and PSM. I have such an animal and the combination of PSM/LSD has led to some interesting moments as the PSM sorts itself out (not quite like it shows in the handbook!) and the rear-end breakaway is brought under control...well sort of anyways. I've only seen a couple of others with the Artic Silver/Space Grey leather combinations....but the mid grey leather is a lot more practical and doesn't show the wear that light grey picks up so easily

Attached image of interior

Not sure what the % lock is the '99 C2, I've got one of these with traction control. I don't think LSD comes with PSM (except for the new ones which I don't understand how the system works with each other).

Pete, I wonder if we both have the same car spec. First off my car is a C2S. Many people have said there wasn't a C2S and there has been much arguing about it. But that's what mine is. It also says it a C2S in the log book, registration papers and purchase papers. Also, PUK told me they only ever appeared in the UK. They have exactly the spec you mentioned. Including LSD. And that's why I have found it hard to get a used gearbox. There is also 030, 18" wheels (although I took mine to 19") and some other suspension mods. Strangely it don't come with red shoes like other S models. Incidentally, your interior is exactly as mine even down to the phone hook switch near your column (is it a Parrot?). Although mine has OBC so there is an extra column switch.

Carlos: The GT3, at least the '04 model, also has the asymetric LSD.

Sorry Steve, I only knew of the GT2's asymetrical Also as to the 98-99 C2 with LSD. They have a T/C not PSM. When the PSM was incorporated, the LSD was dropped and used the ABD for it to be able to work with the PSM. The first LSD/PSM are the 40th edit 911's.

As Carlos points out the 98-99 C2s have T/C, not PSM. PSM became available on the C2 when it went from a mechanical throttle linkage to the EGas system (which the 996 C4 was introduced with). If you look at the lockup percentages between the GT2/GT3 and the 40th Anniversary 911s they're a lot lower in the latter. My guess is that there is a limit how much lockup the PSM system can handle.