The 911 and limited slip differentials: when...

dd74 · 11-07-2007, 02:02 PM

...did they first appear on the cars? Did the Carrera RS have LSD? I'm just wondering.

Thanks.

KTL · 11-07-2007, 02:18 PM

I too will be interested to hear when the LSD first appeared in the production cars. And it's a crime it wasn't standard in every one thereafter............ speaking as someone who's without, and is tired of it.

Early_S_Man · 11-07-2007, 02:45 PM

Early cars used the ZF LSD from the 904 ... only drawback was the Nadella stubs & U-joints that had to be used!

Bill Verburg · Bill Verburg's Garage

Quote:

Originally Posted by dd74

...did they first appear on the cars? Did the Carrera RS have LSD? I'm just wondering.

Thanks.

lsd was an option on 911s from day1. It's not standard because of cost and the penalties it can impose for dd.

an lsd is best when there is uneven traction, it is worst on slick surfaces w/ even traction at all the drive wheels where it induces a powerful slueing motion. Most drivers are better off w/o it on really slick surfaces

einreb · 11-07-2007, 03:48 PM

Quote:

Originally Posted by KTL

I too will be interested to hear when the LSD first appeared in the production cars. And it's a crime it wasn't standard in every one thereafter............ speaking as someone who's without, and is tired of it.

Might I suggest an e36 M3. Any of them... since it was stock.

Geary · 11-07-2007, 03:54 PM

As Bill says, there were Early 901 LSDs available, it just seems that not many made it to the U.S.... so a lot of guys ended up installing 904 LSDs in these early 901 transmissions. All those 901 Early / 904 LSDs utilized plain steel plates, no friction material on any of the discs. (We're actually having modern disc kits for the 904 made right now, primarily for the European market.)

BertBeagle · 11-08-2007, 07:40 AM

Quote:

Originally Posted by dd74

...did they first appear on the cars? Did the Carrera RS have LSD? I'm just wondering.

Thanks.

I posed the question to the men in plaid over on the 356 Registry list (of which I am a member) and some responses indicated that the ZF lsd was an option as far back as the 356. One guy had one in his '64 and says it came from the factory as an option.

From that you might assume that they were an option from day one on the 911.

pieterk · 11-08-2007, 08:26 AM

Quote:

Originally Posted by Geary

(We're actually having modern disc kits for the 904 made right now, primarily for the European market.)

Are these designed to retrofit into existing 904 housings?

How do these kits compare to your new off-the-shelf 901 LSDs? Same internals?

Geary · 11-08-2007, 08:56 AM

The early 356 ZFs were actually a "Jelly Bean" variety, not a plate style. Some time in '08 we'll offer a true LSD for the 356, patterned after our prototype VW swingaxle LSD, which uses proper friction discs, not Jelly Beans:
http://www.thesamba.com/vw/forum/album_page.php?pic_id=355208

The 904 kits that I referred to are for the OE 904, and are somewhat smaller in diameter than the GT version 904. So no, the GT 904 (and 901 Early) internals are not interchangeable with those of the OE 904 (and OE 901 Early).

pieterk · 11-08-2007, 09:06 AM

Quote:

Originally Posted by Geary

The 904 kits that I referred to are for the OE 904, and are somewhat smaller in diameter than the GT version 904. So no, the GT 904 (and 901 Early) internals are not interchangeable with those of the OE 904 (and OE 901 Early).

I should go back and read the literature you guys sent me; superb package! That may have been mentioned.

So I'm guessing that since your 904/early 901 LSD is larger than the OE LSDs, it is stronger and more durable. I've been warned by several authorities that the early 904 LSDs are weak, at least in part due to their size, and that I should actually look for a 911 box (vs. 901 or 915) since they can accomodate the later 915 style LSDs. Too late for that, as I have two 901s!

Either way, when I'm ready to install the box, I'll be ordering your current LSD for my 901.

dd74 · 11-08-2007, 09:18 AM

Geary - pm'd you.

Geary · 11-08-2007, 10:36 AM

Quote:

Originally Posted by pieterk

I've been warned by several authorities that the early 904 LSDs are weak, at least in part due to their size...

The OE 904 LSD has pretty small diameter spider gears and cross pins. We've squeezed much stronger pieces into the GT version.... and I would say that strides in material composition alone make newer high-end parts more durable.