will a ZF type lsd from a 915 work in a G50?

[rpiper]

I think the answer is "no" but does anyone know for certain?

[wevoid]

Bobby,

The answer is no. The 915 is too short between the carrier bearings for the G50 housing.

Regards

Hayden

[rpiper]

Damn. Thanks for the reply though.

[rpiper]

ummm, thinking about... dare I say it... buying a 993. I just rebuilt my 915: all new everything, 7:31 r&p, GT ZF LSD, taller 5th. Contemplating swapping in a stock 915 before selling, since the $4500 I spent on the gearbox last July can hardly be added on to the SC's price.

[Bill Verburg]

Hayden, would a split lockup diff,from a G50/21, say work in a G50 as used in the late Carreras?

[rpiper]

Bill, are you the one who bought that Euro Carrera 915 from me? That was before I even knew about Pelican, and now I am wondering if that was you?

[Bill Verburg]

Bill, are you the one who bought that Euro Carrera 915 from me?

No, the original 915/44 came w/ the car purchased in germany, the replacement 915/67 camr from a wreck in West Palm Beach where my parents lived.

[wevoid]

Bill,

Without researching it too far, my initial reaction would be yes.
I had a 2002 GT3 Cup car diff here recently for an inspection / freshen, I seem to recall it was same basic dims as my "set-up" G50 open diff that I think is from an '87 or '88.
Makes me think they are all much the same from the first G50, thru 964 versions, right up to the current 996tt, the final drive housing on that just looks like a G50/52 with more features added to the casting.

Regards

Hayden

[Bill Verburg]

Hayden,
Thanks thats good to know and may be useful.

[Geary]

Originally posted by wevoid
Bill,

-- all much the same from the first G50 --

-- except that most 6-speed models (including Motorsports LSD) do not have the three holes to accept the 5-spd magnetic speedo ring.

[wevoid]

Thanks Paul, it's knowing those little details that can make it a lot easier to avoid a difficult install...

Hayden

[ChrisBennet]

Originally posted by Bill Verburg
Hayden, would a split lockup diff,from a G50/21, say work in a G50 as used in the late Carreras?

Is the G51/21 a 993 transmission?
If you are considering getting a factory 993 diff, go to the Rennlist Web Forum on Performance Modifications and do a search on "Why are the 993 LSD bad".
Here are some excerpts from what Steve Weiner wrote:
"OMG, You would NOT want the 993's LSD,...its a real POS. Stay away from those."
"1) The number of drive & driven plates is 1/2 of the early ones and they are normally all worn out by 25K miles.
2) The 993 LSD cases are cast, not forged, and are prone to break."

-Chris

[Bill Verburg]

Is the G51/21 a 993 transmission?

Yes, 993RS or 993RSCS or 993Cup

Not all 993 diffs are the same design. These are a very different breed of animal.

I am not necesarily considering this mod.

[Geary]

Originally posted by ChrisBennet
Is the G51/21 a 993 transmission?

"OMG, You would NOT want the 993's LSD,...its a real POS. Stay away from those."
"1) The number of drive & driven plates is 1/2 of the early ones and they are normally all worn out by 25K miles.
2) The 993 LSD cases are cast, not forged, and are prone to break."

The G50/21 is the Euro version 993 6-spd. Identical in every way except the gear ratios.

The friction discs in the standard 993 LSD wear out WAY sooner than 25,000 miles. The good news is that the 993 LSD internals can be replaced with higher quality components, and the proper number of discs.

ALL factory LSDs have a cast body (although the Motorsports 40/60 version is a higher quality casting). The billet GT1 Motosports LSD ($4,000+) being the only exception.

[Bill Verburg]

Beg pardon, my interest is only in the G50/31 and G50/32, which is the split 40/65 lsd, w/ separate second & steel syncro rings. Perhaps Geary can amplify, but I belive that the # of disks was doubled for these?

[Geary]

Oh, yes. The 40/65 LSD has two friction discs per side, rather than just one per side --- AND they are the good friction material, totally unlike those found in the standard G50/20 (993) transmission.

[beepbeep]

Are late 930 LSD's (88' 930 4-speed tranny) also of "inferior" few-plated design?

[Geary]

These would have come from the factory with only one friction disc per side (40% setting), but using the superior friction material. These could easily be converted to 80% with some plate swapping.

[KTL]

Good topic!

My G50 needs a LSD or T-B diff. and my thoughts were that the later (964-newer) diffs. looked to be the same as those used in the early G50 transaxles. My assumptions were based soley on part # comparisons. Like Hayden said, good to know issues like the magnetic speedo problem. Thanks Paul! So that basically limits my options to those 5 speed units from 87-94.

[Geary]

Some of the 993 LSDs have the holes for the earlier magnetic ring.