Which Trans?

[mendo]

I want to know more about the Porche trans, I heard some things about different gear ratios, different years.

is there a "best one"?

how about a list in order of Best to not-as-good.

OK, now, I toss in..... about what will it run!!!!

any info is appreciated!!

I am gathering parts for the build. got the kit, looking for donar Car and trans.

[spytech]

How much power do you plan on putting through your trans?

[mendo]

How much power do you plan on putting through your trans?

stock 2004 power.

[jjm]

Take a look at the california motorsports site .... Lots of comparison info there.

[mendo]

Take a look at the california motorsports site .... Lots of comparison info there.

Wow, now I have more questions, there are about 6 different G50 transmissions.

??

[The Stig]

Mendo,

The G50-xx Porsche transaxles have a bit of a range.

You originally asked what you could expect to have to spend, and what type of horse power and torque they can handle. I am not an expert of the various Porsche Gear boxes. But I have owned Porsches in my past, and always found them to be very nice and easy to use. I'll try to walk through some of the choices, with whatever detail I can recall. If I'm wrong, hopefully someone will step in and correct whatever needs to be corrected.

High Horsepower:
G50/50, and G50/52 (5spd) transaxles were used in Porsche Turbos. They fairly easily can handle the high hp and torque of the Stock LSx series engines. LS1 through LS7. They also seem to be able to handle the ultra high horse power builds. These gear boxes have a 9" ring gear which allows for the higher torque of the Chevy Engines. These are a little more rare than the others, and therefore a quite a bit more expensive. These can run as much as 10k for a used box out of a wrecked Porsche. Rebuilt / Remanufactured versions could run you 15k +.

Standard Horsepower Engines:
G50/20 (6spd) transaxles were used in the 993 Porsches. It uses a 7.5" Ring Gear, which means that the gears will be just a bit short for the LS engines. However, there are quite a few people who have used them, untouched, and have had good results with them. This transaxle works well with the stock LS engines such as the LS1, LS2, and a stock LS3. These transmissions can be found for prices between 3500.00 to 7500.00. You have to really look around to find one, in good shape, at a good price.

Other builders have them remanufactured / rebuilt, with taller 5th & 6th gears, which gives you lower RPMs in the 70 to 80 mph cruise range. Doing this normally adds some serious $$$ to the cost of your transmission. If I'm not mistaken, to switch out the gears in this way, can run you a couple thousand dollars or better.

Another upgrade is to install a beefier side plate. These usually run around 300 to 400 dollars.


G50/01 and 03, are the common (5spd) versions on the G50 gearbox. The same prices can apply as seen with the G50/20. Gear Upgrades should be pretty similar.

With that said, there are some transaxles from the 996 (and I think the 997) that can be used as well. I am not that familiar with these, but i believe that the G96/96 is the 6 spd version used in the Porsche GT2 and GT3. They are capable of handling higher horse power engines, and the gearing is a close match for the LS engines. However, my understanding is that there are some changes that have to be made for mounting this transaxle into the GTM.

Understand that the prices for these boxes can be in a completely different zip-code. Quite a bit more expensive than the G50 transaxles.

My transmission:
I have a G50/03 (5sp) that has been rebuilt, with taller 4th & 5th gear upgrade, Billet Side Plate, has been plumbed to be run inverted in the GTM, and for a transmission cooler. At present, I have about $11,500.00 in my transaxle. I've also bought a specific clutch kit, slave cylinder, and starter to use with the transaxle, which ran around $750.00. I am also using a transaxle cooler to help keep the trans heat under control. $400.00. I am also using a cable shifter, which I believe costs around 600.00. So all in all, I have around $13,250.00 in my transmission.

Knowing what I know now, I think if I were to do it all again, I'd hold out for either a G50/50 (strongest of the G50's) or find a GT3 gearbox at the best price I could find, and then do what is necessary to get it ready to use in the GTM. It will handle pretty much what ever you choose to throw at it.

My point is, that you can spend as much, or as little as you want to in regard to your transmission. Check e-bay for used transmissions, but be carefull about what you buy. Los Angeles Porsche Dismantlers are a good source to check as well. Especially for the G50/50 & 52. I've seen some good prices there. (Again, these will be used).

I think that one of the best deals going right now, for Porsche Transaxles may be with California Motorsports. They are offering a G50/03 (5 spd) Completely remanufactured by Getrag (new), and has been set up to run inverted. $7500.00 plus shipping. This is a good solid transmission to use with stock LS1, 2, and 3 engines. You should give them a call.

I hope that some of this helps to answer your questions. I also hope that most of it is right.

[mendo]

Stig, I appreciate you taking the time to go over all this. this is great information and will help me to make some decisions about how to get a trans that I can make work.

Thanks!!