79' 930 - G50 Conversion

[totle]

Well thought I would make a thread about my G50 conversion.

When I bought the car it had another R&P in the 930 transmission. As I thought the engine cruised a bit high on the highway, I replaced back to stock R&P last year.

After reading about some G50 conversion I decided to do one myself.
I was looking for a G50 with shorten bell-housing, but it was not easy to find at that time.

Bought a G50/00 of ebay in Germany.



Since I did not want to cut the torsion tube I needed to have the Bell-housing and main shaft shortened.

I found a mechanic in Norway that was familiar with the G50 transmission to do the machining for me.
This guy is really a turbo guy, so had to choose him for the job
He is having one of the worlds fastest bug at around 950 hp and uses G50 in his bug dragster.

Then It was just to strip down the transmission, and then clean the housing before sending it away the to the machine shop.
The internals looked very nice with no noticeable wear.

Started with removing the rear cover, 5'th gear and reverse.



Then I need to separate the main shaft.

[totle]

Delivered the bell-housing and main shaft before Easter and picked it up Friday.

Had to take a picture of his famous VW bug. This his record is in the area of 8.2xx something on the mile.

[totle]

Here is what the short bell-housing looks like. The piece on the floor is what was machined off.



Some of the parts going in the conversion.

KEP stage 2 pressure plate with G50 diaphragm, CMS billet aluminum side cover, Carerra pedal assembly with slave cylinder, new master and slave cylinders, Wevo G50 short shift...

[IMR-Merlin]

Let the fun begin. I opted for the torsion tube modification for my project

[totle]

Was in the garage today to test fit the transmission. It was a good fit without any adjustment on the torsion tube.
I see many go for the weld on mounting kit and new transmission cross member.
I will keep the stock chassis mounts and just modify the cross member.

It fitted by moving the cross member a bit forward. Will have to weld a bit and make new holes and the original will fit

[IMR-Merlin]

If I had the cash to shorten the BH, I would have done that AND notched the torsion tube. Imagine moving the whole engine and trans package 2" forward on the chassis. It has to help the weight % front to rear.

[930cabman]

I have owned my 1987 turbo cab for several years now, from what I understand the car is from southern Florida and has a G50 conversion. Other than that the car is basically stock and she rocks. I have seen 140mph at 6800 rpms in fourth gear. I am having an overheating issue and several oil leaks so I am figuring on removing the engine this summer and going at it. I am available to assist with details if anybody needs. My recommendation would be for all 930 owners to convert, it is very cool to have 5.

[Maxx1]

Man, that would be sweet! I'd love a 5 speed. I can't figure out why Porsche stayed with the 4 speed so long.

[Matt Monson]

It is stronger, they had a lot of money invested in inventories (935 and 962 used the same gears) and motorsports homologation. When you have a winning formula why would you change it just to make a street car more pleasant to drive?

[Edelweiss]

Hi again Trond,

If you are in the area - please tell Tor Øyvind that I have 86 mm and 88 mm waterboxer cranks with Chevy bearings available in the next 10 days.

Just in case he is in need for a build...

By the way - this guy is a legend !!!

Best regards from Krautland

Dirk

[gsxrken]

I don't mind the 4 speed, really. Yes it's geared very tall, but I think it matches the turbo power delivery. Even on the track, I've never seen more than 4300 in fourth before it was time to brake. Of course, my 300HP probably has something to do with that.

And every time I look at the guts of a trans, I think they are more complex from a conceptual engineering standpoint than any internal combustion engine.

[quattrorunner]

And every time I look at the guts of a trans, I think they are more complex from a conceptual engineering standpoint than any internal combustion engine.

Mind boggling to me too.

[sjf911]

Originally Posted by gsxrken

And every time I look at the guts of a trans, I think they are more complex from a conceptual engineering standpoint than any internal combustion engine.

Compared to a SBC maybe but I found rebuilding a Porsche motor much more intimidating than the 915 and the 930 is supposed to be easier. Now doing the R/P setup is another story. Having the correct tools on hand makes a big difference.

[Falk930]

Trond,
would you mind sharing the details for the work on the bellhousing.
Especialy I am interested in the exact measurments.

Falk

[lite75]

29mm is the max you can take off the bellhousing.

[jess p]

What is meant by "weld on mounting kit"

[spuggy]

Originally Posted by jess p

What is meant by "weld on mounting kit"

If you keep the G50 cross-member, there's an air gap between the mounts and the chassis. You weld blocks to the chassis so the cross member bolts up, but then you have the same problem with the G50 transmission mounts that folks with G50s have; not user-serviceable (WEVO do an exchange service) and poor choice for alternate mounts (stiffer mounts make a lot of difference).

Another option is a modified 915 cross member from PMS with slotted bolt holes and a sturdy block provided to space it off the transmission so it just bolts up. This takes 915 engine/transmission mounts, which just bolt in. 915 engine/tranny mounts interchange - so you can use any aftermarket mounts as desired.

Another wrinkle when doing this in a 911 is that all 930 sway bars have a kink in them to clear the bigger transmission; pre-G50 911 rear sways don't. So you either source a 930 sway or space them off the ARB console (which allows a wider selection of sizes).

[IMR-Merlin]

Originally Posted by jess p

What is meant by "weld on mounting kit"

Originally Posted by spuggy

If you keep the G50 cross-member, there's an air gap between the mounts and the chassis. You weld blocks to the chassis so the cross member bolts up, but then you have the same problem with the G50 transmission mounts that folks with G50s have; not user-serviceable (WEVO do an exchange service) and poor choice for alternate mounts (stiffer mounts make a lot of difference).

Another option is a modified 915 cross member from PMS with slotted bolt holes and a sturdy block provided to space it off the transmission so it just bolts up. This takes 915 engine/transmission mounts, which just bolt in. 915 engine/tranny mounts interchange - so you can use any aftermarket mounts as desired.

Another wrinkle when doing this in a 911 is that all 930 sway bars have a kink in them to clear the bigger transmission; pre-G50 911 rear sways don't. So you either source a 930 sway or space them off the ARB console (which allows a wider selection of sizes).

What am I missing here? I am running a G50 in my project car. I notched the torsion tube to clear the trans and everything bolted up fine with the G50 cross-member. I haven't tried to bolt on my rear sway bar yet.

Link to page with torsion tube work...
new member 930 project