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Wed Jan 08, 2014 4:38 pm

Anyone know if a Porsche factory 5 speed transmission can be retro-fitted to work in a vw bus? Thanks

Wed Jan 08, 2014 5:02 pm

Given enough time and money, nearly anything is possible.

Wed Jan 08, 2014 5:28 pm

Wheelborrows of cash helps.

Wed Jan 08, 2014 7:46 pm

You could but you'd have 5 reverse speeds and one forward :-P

Wed Jan 08, 2014 8:19 pm

jake raby has been there, done that. search for his double cab thread

Wed Jan 08, 2014 8:19 pm

nicksny wrote: You could but you'd have 5 reverse speeds and one forward
:roll:

Maybe if he used an unmodified 914 or Boxter 'box, but a regular 901/915/G50 transmission is set up for the same rear-engine setup the Bus uses. All it would take for one of those is the previously-mentioned pile of cash. Peeking at Fleabay really quickly, the 901 and 915 are "cheap" around $1200-1500ish, the G50 seems to start at $4000. And then the powerband of the engine is probably going to be "off" from what you need to comfortably move a Bus around (even with a Porsche engine) so you'd be looking at even more money to get it re-geared...

Wed Jan 08, 2014 8:30 pm

from the vanagon thread with similar question:

D Clymer wrote: The only transmissions from the VAG/Porsche empire that will work are Porsche 911 transmissions. There are five basic varieties of these to choose from - and one new exciting one soon to debut:

1. Type 915 Transmission: 1973-1986 Porsche 911. It's a good transmission, and it's compact enough to go in a Vanagon, but it has very poor shift quality and it is set up for cable clutch actuation.

2. G50 Transmission: 1987-1994 Porsche 911. This is an excellent transmission, and the pre-1990 short version would fit a Vanagon very well.

3. G50/20 Transmission: 1995-1998 Porsche 911. This is a 6 speed version of the G50.

4. G96 Transmission: 1999-2005 Porsche 911. Once again a 6 speed Getrag unit. This time it has cable shift actuation.

5. G97 Transmission: 2006-C Porsche 911. This one's gonna kill you, Zeitgeist :) It's made in Japan by Aisin! Yup, with the 997, Porsche stopped using Getrag boxes and started sourcing their manual trannies from Aisin.

6. New 991 Transmission: The new 911 which is due to be released very soon uses the world's first 7 speed manual gearbox. Tell me you wouldn't want that in your Vanagon.

The biggest problem with all of these Porsche gearboxes is supply and cost. The G50s have a used market value of about $2800 and the G97s go for nearly $5000. The 915s can be had for less, probably $1500, but they have lots of miles on them and are also hard to find.

Another problem with using these Porsche trannies, and it's one that a lot of people don't quite get, is the fact that they are geared way too high for a Vanagon. All of these trannies up through at least the G50/20 use a 3.44:1 final drive ratio. For comparison, a typical Audi performance model uses a 4.11:1 final drive. Both have similar 1st gears of about 3.50:1. That gives an idea of just how tall the gearing is on a 911. 911s have typically been geared very high in first gear. It works because the cars are light in relation to the excellent torque of their large displacement motors. But put this in a Vanagon that weighs about 1000 lbs more, and you've got a first gear that's far from ideal. And one thing's for certain. You can't afford to open up a Porsche tranny and have custom ring and pinion gears installed. The later 6 speeds are a bit better. They still use the 3.44 final drive, but their first gear is like 3.82:1 instead of 3.50, but probably still not ideal.

It would be nice if the Audi front drive trannies could be used, but they can't. They just aren't packaged to be able to flip the differential.

There's are some possibilities with Audi automatics, but that's another discussion for another day.

David

and for the 901/902 units, those can and have been used in our bays. they won't really push the additional weight and increased hp numbers most vanagon owners are looking to upgrade to so that's why they skipped over them.

ratios for those are here:

http://forums.pelicanparts.com/uploads18/porschetrans11284954474.jpg

http://forums.pelicanparts.com/uploads18/porschetrans21284954498.jpg

901/902's can be had for reasonable amounts if you go searching outside of the ebay realm. i've got a 902 sitting in the garage at present that's going into my 69' westy when the time comes 8)

Wed Jan 08, 2014 8:32 pm

nicksny wrote: You could but you'd have 5 reverse speeds and one forward :-P
That's a 923 (912E) gearbox.

Wed Jan 08, 2014 9:13 pm

Not that hard to do with a 901/923/915 tranny and all of them will last a long time with 300hp. They are not speed shifting trannies but gosh Porsche raced with them and they were built to last.
914's use the 901 trannys with a different shifting setup plus the diff is flipped so yeah you would have 5 speeds in reverse unless you flipped the diff.

I have seen only one bus done with a 901 and it also had a 911 T engine in it. I don't see why you would need boat loads of cash as it wouldn't be too hard to do. I have thought about swapping one in....too many other projects

Wed Jan 08, 2014 9:40 pm

Make sure you have plenty of torque, a proper power band, plenty of thermal conductivity and an efficient cooling system, first.

If not 5th gear will just create a thermal reactor in a heavy, non aerodynamic bus.

Properly configured, its awesome..

Thu Jan 09, 2014 7:43 am

a1steaksauce wrote: from the vanagon thread with similar question:

D Clymer wrote: The only transmissions from the VAG/Porsche empire that will work are Porsche 911 transmissions. There are five basic varieties of these to choose from - and one new exciting one soon to debut:

1. Type 915 Transmission: 1973-1986 Porsche 911. It's a good transmission, and it's compact enough to go in a Vanagon, but it has very poor shift quality and it is set up for cable clutch actuation.

2. G50 Transmission: 1987-1994 Porsche 911. This is an excellent transmission, and the pre-1990 short version would fit a Vanagon very well.

3. G50/20 Transmission: 1995-1998 Porsche 911. This is a 6 speed version of the G50.

4. G96 Transmission: 1999-2005 Porsche 911. Once again a 6 speed Getrag unit. This time it has cable shift actuation.

5. G97 Transmission: 2006-C Porsche 911. This one's gonna kill you, Zeitgeist :) It's made in Japan by Aisin! Yup, with the 997, Porsche stopped using Getrag boxes and started sourcing their manual trannies from Aisin.

6. New 991 Transmission: The new 911 which is due to be released very soon uses the world's first 7 speed manual gearbox. Tell me you wouldn't want that in your Vanagon.

The biggest problem with all of these Porsche gearboxes is supply and cost. The G50s have a used market value of about $2800 and the G97s go for nearly $5000. The 915s can be had for less, probably $1500, but they have lots of miles on them and are also hard to find.

Another problem with using these Porsche trannies, and it's one that a lot of people don't quite get, is the fact that they are geared way too high for a Vanagon. All of these trannies up through at least the G50/20 use a 3.44:1 final drive ratio. For comparison, a typical Audi performance model uses a 4.11:1 final drive. Both have similar 1st gears of about 3.50:1. That gives an idea of just how tall the gearing is on a 911. 911s have typically been geared very high in first gear. It works because the cars are light in relation to the excellent torque of their large displacement motors. But put this in a Vanagon that weighs about 1000 lbs more, and you've got a first gear that's far from ideal. And one thing's for certain. You can't afford to open up a Porsche tranny and have custom ring and pinion gears installed. The later 6 speeds are a bit better. They still use the 3.44 final drive, but their first gear is like 3.82:1 instead of 3.50, but probably still not ideal.

It would be nice if the Audi front drive trannies could be used, but they can't. They just aren't packaged to be able to flip the differential.

There's are some possibilities with Audi automatics, but that's another discussion for another day.

David

and for the 901/902 units, those can and have been used in our bays. they won't really push the additional weight and increased hp numbers most vanagon owners are looking to upgrade to so that's why they skipped over them.

ratios for those are here:

http://forums.pelicanparts.com/uploads18/porschetrans11284954474.jpg

http://forums.pelicanparts.com/uploads18/porschetrans21284954498.jpg

901/902's can be had for reasonable amounts if you go searching outside of the ebay realm. i've got a 902 sitting in the garage at present that's going into my 69' westy when the time comes 8)

Plus there are tons of used good gear sets around for 901's for cheap so you can gear your tranny how ever you want pretty easy as the 901 isn't too tough to take apart and work on. I would set it up so the 5th gear keeps the engine rpm at the same as stock or you will cook the engine due to lack of fan speed.

Thu Jan 09, 2014 8:24 am

The OP has two post to his name and they are both about whether a Porsche trans can be used in a baywindow bus or a late model bug. Weird?

Thu Jan 09, 2014 8:28 am

Keith wrote: The OP has two post to his name and they are both about whether a Porsche trans can be used in a baywindow bus or a late model bug. Weird?

Keith - you noticed that too - here are some threads here that have discussed this before. Search would have brought them up.

http://www.thesamba.com/vw/forum/search.php?search_keywords=porsche+transmission&search_forum=5

Thu Jan 09, 2014 8:29 am

Keith wrote: The OP has two post to his name and they are both about whether a Porsche trans can be used in a baywindow bus or a late model bug. Weird?
Agreed... let's wait till he replies. Otherwise we're rehashing old info.

Thu Jan 09, 2014 5:35 pm

Thanks for all the info and help. I have posted a 914 tail shift trans here on the samba and have had several people who wanted to know if these units could be used in beetle and/or buses as well.

I told them I'm not sure and just trying to get info so I can give an honest answer. I'll give them this info and possibly they can know before getting into something that's not going to work

Thanks again. Bill

Thu Jan 09, 2014 10:36 pm

ADIDAS wrote: Thanks for all the info and help. I have posted a 914 tail shift trans here on the samba and have had several people who wanted to know if these units could be used in beetle and/or buses as well.

I told them I'm not sure and just trying to get info so I can give an honest answer. I'll give them this info and possibly they can know before getting into something that's not going to work

Thanks again. Bill

Only if you install a cable shifter setup and flip the diff. A 914 tail shifter nose cone isn't anything like a bug/bug/911 with a straight rod sticking out of it. Swapping in a 911-901 nose cone is easy and they are around off junk trannys.