Graz vs GT3

[Jeff W]

I got offers on the table for a newer GT3 transaxle and a slightly older L140. I guess I’m pretty familiar with with the expected Graz costs, but I’m not at all familiar with the GT3. How’s the gearing? Can it stand 500 hp/490 ftlb torque? Parts costs/difficulty to fit in the SLC vs Graz?

 

[Ken Roberts]

Scott Swartz has a Ricardo for sale if you might be interested.

 

[Tom]

You might want to be more specific re the GT3 tranx you have in mind. As a rule, Porsche tranx are quite strong and more importantly, have very good parts support, including gearing options.

 

[Jeff W]

Unfortunately there’s no online decoder to find out the specific trans type. All I know is that it’s from a 2018 GT3. I’ve got a friend of a friend who works for Porsche and I’ve sent the serial/model along to see if someone can decode it for me. My digging seems to indicate that it might be the lower horsepower model, but I’m hoping to get confirmation.

 

[Howard Jones]

Call California Motorsports and ask them. They are very well versed in Porsche gearboxes.

Porsche transmissions, parts, service and manufacturing

Porsche transmission rebuild transaxle repair racing parts 356, 901, 915, 930, 944, 968, G50, 993, 996, 997, 991, GT2, GT2RS, GT3, GT3RS, CUP, Cayman, Boxster, Spyder, 981 gt4, porsche 996 997 front differential rebuild, CMS parts, billet, axle flange, side cover, shift fork, intermediate plate...

californiamotorsports.net

Here's what they have online for GT3 GRBX's. It looks like the gear ratios are the main difference, I see that they all use the large 9 inch R&R.

PORSCHE 996/997 PORSCHE GT2/GT3 TRANSMISSION SPECIFICATIONS

G96/88, G96/90, G96/93, G96/96, G96/97, G97/88, G97/96

californiamotorsports.net

If your's is from 2018 then it's the latest version and IMHO has the best gear ratios for a V8. 1st is somewhat low but would be great for traffic lights, slow traffic, parking lots, trailer loading, etc. The rest, 2nd -5th would be a good track/ street combo and net you a top speed above 175 MPH. The 3.44 final is perfect as far as I am concerned.

 

[Jeff W]

Thanks for the knowledge boost on the Porsche axle! I’ll give them a call and see what they say.

 

[Jeff W]

Big thanks for the CMS contact, saved me a bundle. The particular transaxle is a rare one, so hard to find parts for they don’t service them, and the gearing is too close for a V8.
IOW, I probably couldn’t fix it if I broke it, or get better gears.

 

[Tom]

^ good catch. Maybe see about finding a G96/96 or something similar - they came out of GT3/Cup car in the mid 2005-8 era. Compact, robust, and good parts avail. The new tranx seem to be very good, but almost disposable. You might also talk with BMC&G in Ohio, they do a ton of Porsche tranx for racing.

 

[Jeff W]

Done.

Picked up the L140 and having it sent to HCF. Figure it’s a good deal as it’s a little older setup off of a V10 Gallardo and the V10 tranx off the Audis are all more than double the price.

Two biggest items outside the kit are bought, noI just need to slowly clean up some space and get everything in order so I can order the car next year.