Are there any easy choices for upgrading the 4 speed in a 930?

[Maxx1]

Are there are any bolt up 5 or 6 speed transmissions for this car? I doubt I'd ever go that direction because it's probably too expensive and would devalue the car, but just for argument's sake, can it be done? I'm thinking a 6 speed in this car would be great, especially a sequential shift.

[clutch-monkey]

paging Uncle.. i think he was talking about Ruf five speeds for his car. wasn't cheap but not unattainable from memory

[turbobrat930]

I put the G50/50 in my car. I did the camber boxes in the rear, as well as torsion bar delete and coilovers at the same time. All said the trans swap was about 12 grand (and that was 15 years ago)....

I talked with Patrick Motorsports a few weeks ago, and the tech I was talking to said the G-50/50 was getting as rare as hen's teeth... and if they had one to sell, it would go for about 25K !!!!!!

[gumba]

For street use a shorter r&p is the best bang for the buck.

[sundevil64]

Originally Posted by gumba

For street use a shorter r&p is the best bang for the buck.

Why change the r&p and not do custom gearing to get what you are looking for in street manners and keep the long legs of the 4rth gear? Just curious.

[gumba]

A friend that builds race transmissions made a few gear charts for the 4 speed and came to the conclusion that the 8:39 was so close to what he considered a good custom gear set up for street use it was cheaper to go with the r&p.
I would also think (just my .02) that if you went with a short 1-2-3, or 2-3 and kept the stock 4th you would have a significant rpm drop that would drop you out of the power band.

[Hams930T]

Originally Posted by sundevil64

Why change the r&p and not do custom gearing to get what you are looking for in street manners and keep the long legs of the 4rth gear? Just curious.

I'm guessing cost. R&P would run you in the $900 range. Each gear will run you $500-600 if you changed all four and you'd have to tear down the whole box to install them.

Just a thought.

With that said - I think a combo of the R&P and gears would do the trick depending on the use.

I'm currently doing a G50/01 swap into my 86. It's not a cheap exercise.

Chris.

[fredmeister]

I had heard myabe it was rumors that the r&p options available were not too durable and that they might be questionable in terms of lasting as long as the stock unit.
Thats why I considered custom gears a better choice. I may be off base as its been a long time since I was looking into any of this.

Can anyone validate whether there are r&p set options that would take the loads from the 930 engine that could be used in the 4 speed box?

If so what gear ratio options are out there?
----Stock is a 9:38 ring and pinion

thanks,
Fred

[Maxx1]

R&P may be a better option, I rarely drive it over 100 mph anyway. As is, it's not a big issue considering the engine has so much low end torque.... still it would be nice to have harder acceleration up to 100 or so.

[gumba]

Today I think your in the $2000 and up range for a r&p. Not sure what a used one goes for. In '07-'08 I paid $700 per gear (Guard)for our 915 race trans., not sure what they are today.

[PcarPhil]

*Disclaimer* My 930 is built for VA country road / mountains driving. Minimal long distance highway use. After saying that....

Last year I was looking at short gearing choices for my 930 trans including replacing the R&P. The R&Ps are pricey and require specialized setup so it's not really any cheaper vs. buying individual gears. So I ended up moving the stock 3rd gear to the 4th gear position, then going with aftermarket short gears for 1, 2, and 3.

California Motorsports did the work for me including sourcing the gears. The short gears have significantly minimized turbo lag and has simply made the car a blast to drive on the street.

If I did a lot of long distance highway driving or track use I wouldn't have setup my trans up this way or I would have gone with a G50 5-speed.

For me it's perfect!

1st GT 14:39
2nd Albins 20:34
3rd GT 24:29
4th (OEM 3rd) 28:25

[onboost]

So I also got to thinking the other night after a discussion around 5 speed transmissions for the 930.

A friend of mine really wants to do a G50 conversion but he’s really put off at the thought around the associated fabrication work, disassembly and having the G50 cut down, and additional work needed to the car for fitment., altering the torsion bar tube, addition the hydraulic line, and the pedal cluster and reservoir, the easy part. Lastly of course is the price. By the time you’re finish this mod you’re around $11k

Then of course there is the infamous Ruf 5speed trans.. if you can find one. The last time I looked they were fetching between $8 - $10K depending on how fond of it the owner is.

Over the years I’ve seen a couple of these up close and personal and visually they don’t look much different than our standard 4 speeders.
The rear nose cone where the shift rod exits is the noticeable difference. The bell housing and center section appear to be the same and thus it appears that the 5th gear is added to that rear section requiring a specific redesign for the nose cone.

Has anyone here actually seen the inside of this area on a Ruf 5spd, how different is it, and what would be the prospect of duplicating/ reverse engineering this old technology..the addition of a gear, slider, forks, lengthened rod.. what? And yes, the machining, modification, or casting of a nose cone….

[Ronnie's.930]

Originally Posted by gumba

For street use a shorter r&p is the best bang for the buck.

Not if your street use is mostly highway (like mine is).

[TDIDog]

I also had California Motor Sports rebuild and change the ratios of my gear box. Left 1st stock, changed 2, 3 & 4th. There was an altered R&P in, but it failed, I don't think it was set up properly, so I went to stock R&P. I'm quite happy with it now. Get about 1500 rpm drop between shifts.

[ficke]

Originally Posted by onboost

So I also got to thinking the other night after a discussion around 5 speed transmissions for the 930.

A friend of mine really wants to do a G50 conversion but he’s really put off at the thought around the associated fabrication work, disassembly and having the G50 cut down, and additional work needed to the car for fitment., altering the torsion bar tube, addition the hydraulic line, and the pedal cluster and reservoir, the easy part. Lastly of course is the price. By the time you’re finish this mod you’re around $11k

Then of course there is the infamous Ruf 5speed trans.. if you can find one. The last time I looked they were fetching between $8 - $10K depending on how fond of it the owner is.

Over the years I’ve seen a couple of these up close and personal and visually they don’t look much different than our standard 4 speeders.
The rear nose cone where the shift rod exits is the noticeable difference. The bell housing and center section appear to be the same and thus it appears that the 5th gear is added to that rear section requiring a specific redesign for the nose cone.

Has anyone here actually seen the inside of this area on a Ruf 5spd, how different is it, and what would be the prospect of duplicating/ reverse engineering this old technology..the addition of a gear, slider, forks, lengthened rod.. what? And yes, the machining, modification, or casting of a nose cone….

In the 930 transmission they only have two shafts, an input and an out put, there is no third lay shaft. The out put shaft on the Ruf 5-speed is longer than the 930 transmission and the 1st gear is hung on the end of it like in a 901 Porsche box ( I am sure where Ruf got the idea) hence the dog leg shift pattern. Then Ruf uses 935 gears to get the spacing they want.
Since the out put shaft has the Pinion gear it would be very expensive to change the R&P on a Ruf 5-speed.
Ruf 5-speeds were great because Porsche did not have a 5-speed at the time that could take the power of the 930, but in today's world we have access to the G50. I would recommend using a shortened bell housing G50 and regulate the Ruf to the stop gap, interesting, historical, classic category and not a good answer for people who want bang for buck and versatility.
I have a Ruf 5-speed in my car.

[ficke]

Here are pictures of the 1st gear on the Ruf 5-speed

[gumba]

I would talk to Wevo. If there is enough interest he might, at least come up with some cost estimate to see if it's worth it to pursue. He's just finishing up a 5 speed conversion for the 356.

[sundevil64]

I would be interested if it is reasonable.

[IMR-Merlin]

I went the G50/01 with my build, as others, I did torsion bar delete and notched my torsion tube.

I used these guys for info to get gear ratio charts.

California Motorsports - Porsche transmissions, transaxles, gears, differentials, parts, service, manufacturing

[kenikh]

Guard still makes an R&P, but it isn't the 8:39 listed above. It is 8:41, so even shorter. Here's a ratio comparison:

9:38 4.22
8.39 4.875
8:41 5.125

Sounds too short for regular highway work.