G50 Transaxle

[Rowie]

I am thinking of building a Ultima Can-Am. I have the chance to buy a G50 transaxle from a 1990 Porsche Carrera 964 C2 with i/d numbers of g50 301 3016R.

Would this be suitable for a Can-Am with around 450 bhp? I know I won't need it for a good while yet, but as it's being offered....

Thanks,

Ian

[steve_d]

That number does not seem right to me. It would appear to be a G50/30 which I've never heard of before.

Steve

[Rubi]

steve_d said:

That number does not seem right to me. It would appear to be a G50/30 which I've never heard of before.

Steve

G50/30 was 6 sp. fitted to 993 Carrera Cup cars - very desirable I'd say.

Unfortunately if the box you are looking at is the one on fleabay then I'm afraid it isn't a G50/30 as the number quoted is a casting number. The real serial number is stamped on the top of the box (in the Porsche). A 964 of that vintage will probably be a G50/03. I've got one in my Ultima - it is OK but would benefit from ratio optimisation.

[Rowie]

Thanks for the replys.
Yes, it is the one on Fleabay - I thought that it looked like a bargain, am I wrong? If so, what should I be looking for and how much?

Cheers,

Ian

[Paul.B]

Not sure about now with the 600 & 700 bhp cars that are about, but when I built my 1st car in 2000 the 6-speed G50's were not as popular as the 5-speed units. The gearing in the 5-speed suited the power units being installed at that time. 350 - 500 was about the full range. Some were over 500 but very few. One of the factory demo cars (9 FC) went from 6-speed to 5 after the 6 failed.

Paul.B

[Rubi]

Rowie said:

what should I be looking for and how much?

The choice of gearbox is really dependent on the engine it is going behind specifically what it revs to and how much torque it has - as has been said on here before. Wayne made a good point the other day when he commented how much people spend on engines then just make do with whatever Porsche thought was good for their flat 6.

I have 450 to 500 hp and can rev to 6.5k, I agree with Paul B that, on the road, a 6 speed G50 (with "as built by Porsche" ratios)would not be of any benefit with my engine as there is so much torque from the SBC that even with the G50/03 I miss out gears when I only wish to get places quickly, an extra gear would only serve to confuse me! However if I was racing it might be worthwhile as I'd have more options for the corners. But even then I think that the G50/21 (most common 6sp. from a 993) has too low a first gear ratio (it is lower than the "03" ) to be relevant to racing.

When I said that the G50/03 was OK what I meant was with my engine it is fine - it has not croaked and the oil is clean. But if and when I get round to it (subject to other projects) I fully intend to alter the gear ratios as they are not ideal and can be improved.

Edited by Rubi on Tuesday 15th May 10:23

[peterpsg]

I have a G50/21 6 speed, and to be fair I can quite easily go 2-4-6 in that order and reverse.

Starting in 2nd is fine, except in the wet of course, and with our (usually) very heavy clutches and lack of power steering I definately like having the very low first gear for parking purposes...

So I think of the 6 speed box as a 5 speed with 'valet' gear... :-)

[mogg]

peterpsg said:

I have a G50/21 6 speed, and to be fair I can quite easily go 2-4-6 in that order and reverse.

Starting in 2nd is fine, except in the wet of course, and with our (usually) very heavy clutches and lack of power steering I definately like having the very low first gear for parking purposes...

So I think of the 6 speed box as a 5 speed with 'valet' gear... :-)

Agree completely. I have the same box and 540 bhp. Works well on track too - well the tracks I've tried so far ! Not really missing a LSD either so far, although having Kumho track tyres helps there :-)

[peterpsg]

mogg said:

peterpsg said:

I have a G50/21 6 speed, and to be fair I can quite easily go 2-4-6 in that order and reverse.

Starting in 2nd is fine, except in the wet of course, and with our (usually) very heavy clutches and lack of power steering I definately like having the very low first gear for parking purposes...

So I think of the 6 speed box as a 5 speed with 'valet' gear... :-)

Agree completely. I have the same box and 540 bhp. Works well on track too - well the tracks I've tried so far ! Not really missing a LSD either so far, although having Kumho track tyres helps there :-)

I had Quaiffe stick in one of their gear type LSD units after a few hairy sideways moments on my Pirelli's, makes the back much tamer now, and it's easier to correct when it goes awol... but on slicks you might not notice it so much, until the back really goes out!