kurquhart

Cheaper labor, used parts, or what?

Cupcar

I find the G50/32 to be a much nicer gearbox for all around use than the G50/10 that came with my car.

First is the same in both boxes (Bill has a mistake in his spreadsheet, the first in the G50/10 is a 13:41 gear) and 2,3,4,5 are all lower/closer and 6 is just a touch taller for the road.

Geoffrey

Less expensive labor, has a number of used race parts or can supply new, and has worked with Brian Copans at the ALMS races rebuilding gearboxes.

You can find much of the parts yourself. For instance, I found a 993C4 gearbox that was stuck in 6th gear and bought it for $450, I bought 4 used gears for $300 each, bought a new 8:32 ring an pinion, new steel syncros, used steel shift forks, a new C2 tail shaft cover, new 997 GT3RSR 8 plate LSD, new nylon trans mount and it cost me about 4k complete to build the gearbox (labor was free obviously). I later sold the C4 ring and pinion for $600, sold some of the stock gears for $200 each and was able to reduce the cost that way.

Bill Verburg

Thanks, I corrected the g50/10 info and added G33,50,52 & 54 data

What else?

Ritter v4.0

Does a 993 TT use the same G50/20 trans as the NA car? That might make a could swap for each; or 964 5-spd for TT 6 speed. Then re-gear the 6 spd if you can.

Trying to find a willing TT owner could be a challenge.

Geoffrey

You can install a 993TT 6spd in the 964, it bolts in. However, the case is larger to allow for a larger diameter (stronger) ring an pinion. The gears themselves will interchange though. I would not use a small ring and pinion transmission with a turbo car. The G50/52 is also a large ring and pinion trans.

Ritter v4.0

So in theory a good swap- but in practice not so much.

Good source for Cup 996 LSD?

Geoffrey

PMNA

Ritter v4.0

Cheers.

What configuration are the Cup LSD's or are they configurable? I'm looking for 40/60 (65).

Geoffrey

All GT3 race LSDs are 40/65. In my opinion, for a dual purpose car, a used GT3 Cup 4 plate differential will give you the best street/track performance. The 8 plate GT3RSR is very tight for street driving.

Bill Verburg

No, the 993tt uses a G64/42 or /51 depending on the year, as Geoffrey said they can be adapted to 2wd by changing the nosepiece

Bill Verburg

The 993tt G64 wouldn't make a good n/a track trans
the lsd is the same GKN as the n/a 993, not the more robust 4 plate PMS unit used in the /3xs

the G64.51 7.52 used in the 993tts is even taller than the 2wd 993 boxes,
ratios3.818 2.150 1.560 1.212 0.973 0.750
sspeeds 38 67 93 119 148 193

Geoffrey

You also need to machine the pinion shaft to cut off the 4wd splines and viscous coupler OR replace the ring an pinion with a 2wd version

Cupcar

Does the G50/32's 40/65 have a 4 plate LSD?

Tom W

I don't remember if the LSD that came with the G50/32 was a 4-plate or not. It was not the original LSD from in the 90's (like what would have come with a /20 or /21), the LSD that came with mine appeared to be the motorsports version and used carbon fiber plates. I don't know if I have any pictures of it, I'll look.