Bill Verburg

Sticking to your claim that cwp are the same
964 g64 uses 964.302.911.05 which is concentric w/ the hollow main shaft
964 g50 uses 950.302.911.05

these are not even remotely similar other than in grossest terms
I'm signing off here as a complete waste of my time

alexjc4

Ah yes slightly different pn then. But still 31:9 ratio though. What's the chance the ring gear is the same? And the bolt pattern too? Wouldn't be unheard of, the 964 c4 89 part number clutch uses an identical dimension disc, flywheel and pressure plate to the 950 part no item, though elements of the mechanism are different.

Take a chill pill Bill. We're only talking about cars here.

Marc Shaw

That's too bad as I was learning stuff.

Marc

kos11-12

Going back to gearbox ratios, did the Swiss box had 1st & 2 nd as RS ....?

alexjc4

Interesting q Kos the part nos are in PET and they give the ratios so you could check. This site would indicate that you can get RS ratios in the swiss c4 http://www.gboxweb.com/g50specs.html

Re the swap to an lsd , the 928 guys have done this with the psd diff - which shares internals with the c4 diff along with control mechanism. https://rennlist.com/forums/928-foru...n-an-auto.html

alexjc4

I'd been mulling this topic prior to OP putting the question.

The G64 is heavily based on the G50
The transmission case is the same part no c2/c4
The transmission cover is the same pn

This means the position and critical dimensions of the pdas diff are the same as a c2 open diff and a c2 lsd.

The r&p are different because the p shaft runs inside the gearbox output shaft which is hollow but the p gear position is likely the same and The ring gear has 12 bolts so I guess it has the same pcd/ bolt pattern so is likely the same dimensions. I'd bet you could use your c4 ring gear on you c2 lsd.

The bearings are the same dimensions but a different pn on one side , but you'd put new bearings in anyway and use the c2 pns.

The output shaft flanges are different as are the bolts that hold them in. They are unequal lengths on the c4 80/90mm and equal on the c2 85mm but as you can see the total length is the same. For obvious reasons you need the right length bolts too.

I haven't looked at the drive shaft cv joint sizes but there are two flange sizes for the c4 and only one matches the c2 (the larger one i think?). You may need to change drive shafts to match if your c4 uses the wrong size for the c2 flange.

I already talked about removing the c4 diff actuating stuff.

What else? Other than why you'd do it? Maybe a modern atb diff would be fun to try at least. But the total cost might be $2000.

There is a c2 diff case (no pinion gears in it) on ebay in the uk for £50 - that would allow a dry fitting to test the interchangable ring gear theory without too large a cost.

njansenv

I believe a few people have put the C4 LSD into C2 transmissions and basically applied hydraulic pressure manually to tune the diff, for what it's worth. It wouldn't be too difficult to rig a mechanical system using something like a master cylinder with a screw adjustment to tune pressure.

alexjc4

Interesting, sounds similar to the c4 lightweight setup.

peritus

+1

peritus

I just picked up Adrian's 964 book and spent about 3 hours reading it today like a harlequin romance. I learned a ton, especially on this topic. I recommend it.

964s do all kinds of cool stuff.