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Hello everyone,
I have a tuned 964 C2 with a standard 5 speed manual. The car was modified into a 3.8L from 3.6L which also added around 50hp so the car is now at approximately 300hp. My client wants to install a 6 speed manual e.g. from RUF (like in yellowbird) or just a manual from the 993 (which is also 6 speed).
Do you have any suggestions on what gearbox to get and perhaps where from?
Hello everyone,
I have a tuned 964 C2 with a standard 5 speed manual. The car was modified into a 3.8L from 3.6L which also added around 50hp so the car is now at approximately 300hp. My client wants to install a 6 speed manual e.g. from RUF (like in yellowbird) or just a manual from the 993 (which is also 6 speed).
Do you have any suggestions on what gearbox to get and perhaps where from?
300Hp out of a 3.8 l swap. I am assuming a bit more was done to get there.
Unless you need a tall 5th or 6th most will just swap gear sets to suit the power curve of the engine in the 5 speed. IMO money worth spending over engine mods. Using a stock US 6 speed 993 trans G50/20 won't gain you much other than a slightly shorter 4h and 5th with a tall 6th for top speed. The RoW G50/21 is IMO a much better box with shorter gears 2nd through 6th. If this is a US spec car the 5 speeds had a ring and pinion swap in '92 IIRC from 3.444 G50/03 to 3.333 G50/05. Increased top speed of each gear slightly.
Most people if they go the 6 speed route will use the gearing of a G50/30/31 or 32 6 speed box but assuming you can find one you will be well into $20k or more easily these days. You will loose top speed if you go this route as they all top out between 163 and 176 vs the G50/20's 186. I use something similar to a G50/31 in my track car but it will have roughly 600 rwhp if it ever gets completed.
Hello everyone,
I have a tuned 964 C2 with a standard 5 speed manual. The car was modified into a 3.8L from 3.6L which also added around 50hp so the car is now at approximately 300hp. My client wants to install a 6 speed manual e.g. from RUF (like in yellowbird) or just a manual from the 993 (which is also 6 speed).
Do you have any suggestions on what gearbox to get and perhaps where from?
not sure what year the donor car is but here's' a comparison of g50/03, g50/05 964 5 speeds w/ a g50/20 US 993
I did a little digging and couldn't find a recent sale to give you some idea of what a RUF R50 would sell for these days.
Matt Monson of Guard Transmission posited a value of ~20k for one back in 2015, but with the cars appreciating as much as they have since then I have to assume that's gone up significantly.
Today, as Anthony points out, you should expect to spend 20k+ for a decent 993 G50/3 of any nature. That might be better for your application anyway as the R50 is geared for a pretty different car (turbocharged, 400+hp, etc).
I did a little digging and couldn't find a recent sale to give you some idea of what a RUF R50 would sell for these days.
Matt Monson of Guard Transmission posited a value of ~20k for one back in 2015, but with the cars appreciating as much as they have since then I have to assume that's gone up significantly.
Today, as Anthony points out, you should expect to spend 20k+ for a decent 993 G50/3 of any nature. That might be better for your application anyway as the R50 is geared for a pretty different car (turbocharged, 400+hp, etc).
That's correct, generally turbo cars use much taller gear stacks that are totally inappropriate fot n/a use
a /21 and ./31 have nearly the same gearing, the /3x have better syncros, bearings forks etc. the /21 still has the really short first tlike the /.20 though
Finding any g50 6 speed will be the challenge. If you find one then you can pay to re-gear it. I was able to fine a 993tt box which I then re-geared for my car. Since that time 5 year ago I have not seen any other 6 speeds for sale. Others that are more connected may have some leads. I have also heard of people adapting 6 speeds from water cooled cars but I have no idea what's involved with that.
So I am a little confused, My understanding is the RSA''s were all 93 and 94 MY cars. In 92 Porsche changed all the gearboxes for US spec 964 C2's to G50/05's and only the earlier cars had the G50/03's.
I went through this. I installed a g50/20 in my 964 and it made no difference. I couldn't even use 6th gear unless I going at least 85mph (too bogged down) so it was pretty much pointless.
HOWEVER - I then installed an 8/32 R&P and boy did it ever wake up the car !! I know some people don't like the 8/32 but it works for me.
So now my 6th gear is pretty much geared like the old 5th gear in the g50/03 plus I have an extra gear in the middle. 1st gear is almost instant and in typical g50/20 fashion there is a pretty big drop between 1st and 2nd but I don't find it too bad.
My car is a lightweight hot rod so this mod made a huge difference. If I had to do it again, I would do the exact same thing. I'm very happy with it and get a kick out of people's surprised face when I walk on cars with 3.8's and even kept up dead even with a 4.0 with gt3 intake etc and also a Singer.
So I am a little confused, My understanding is the RSA''s were all 93 and 94 MY cars. In 92 Porsche changed all the gearboxes for US spec 964 C2's to G50/05's and only the earlier cars had the G50/03's.
If you are referring to this chart, RSA only refers to the aero package, all C2 including RSA have the same engine. Yes, RSA would have had the /05 which is a far worse performer than a /03
I went through this. I installed a g50/20 in my 964 and it made no difference. I couldn't even use 6th gear unless I going at least 85mph (too bogged down) so it was pretty much pointless.
HOWEVER - I then installed an 8/32 R&P and boy did it ever wake up the car !! I know some people don't like the 8/32 but it works for me.
So now my 6th gear is pretty much geared like the old 5th gear in the g50/03 plus I have an extra gear in the middle. 1st gear is almost instant and in typical g50/20 fashion there is a pretty big drop between 1st and 2nd but I don't find it too bad.
My car is a lightweight hot rod so this mod made a huge difference. If I had to do it again, I would do the exact same thing. I'm very happy with it and get a kick out of people's surprised face when I walk on cars with 3.8's and even kept up dead even with a 4.0 with gt3 intake etc and also a Singer.
I agree, the/20 has that ridiculously short 1 and equally ridiculous 6, in the middle it is closer to a /03, which isn't bad, than to a /05
10-13-2023, 04:02 AM
964 3.8L gearbox swap (5 speed —> 6 speed)
