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  #1  
Old June 21st 2006, 16:55
tdc911 tdc911 is offline
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Unhappy Which Porsche gearbox???

I've read abouth 100 threads on this forum abouth the porsche gearbox conversion but I need some help. I'm completely lost....

I want to put a porsche 5 speed gearbox in my beetle. Now the question is which one do I need to buy? I know I can chose 2 gearboxes to do this: 901/911 or 914. Which one would be the best for the conversion and which one will be the easiest to find?

I have a 2.4l type 4 engine with 200 BHP. Which gearbox has the best gear ratio's? (Or is there no difference?) I've also learned that I need to change the clutch release bearing. Could someone explain it to me please.

Some people told me that the porsche gearboxes aren't that strong and that they break easily when driven sportively... Is this true?

What would be an honnest price for a good porsche gearbox at this moment?

I know I must look like an idiot with al my questions but I want to be well informed before I start converting my beetle...

Friendly regards,

Tom De Coster,
Belgium
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  #2  
Old June 21st 2006, 22:50
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wrenchnride247 wrenchnride247 is offline
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You forgot about the 915 tranny . It can handle the 200bhp easily in stock form. The 911 started using this tranny in '72. From '72-'74 it had a 7:31 R/P. Then in '75 it got a 8:31 R/P. The 915 case was made of magnesium from '72-'77, then switched to aluminum case in '78 for better strength.

If you "drag race start" any stock Porsche, or VW tranny in first gear it will not last long.

You should check out Martin from www.bugat5speed.de he also has a section here on Germanlook in the vendors section.
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1970 T1 W/MassIVe 2913cc RAT/?EFI? w/direct fire (very soon) and 915 trans

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  #3  
Old June 22nd 2006, 03:19
tdc911 tdc911 is offline
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The 915 box is a very good box. I have had some experiance with it. (I've put 300 BHP on a 915 box and it never broke. It just got pretty hot so I upgraded it with an oilcooler.) The car I'm talking abouth was a porsche 911 so there was no real conversion. (It was actually the stock gearbox). Now the 915 is bigger than a 901/911 box. Will it fit as easily as an 901/911 box into my beetle? Are the gear ratio's from a 915 ok for a type 4 engine because they were originaly designed for a flat 6 engine with a lot of torque?

Grtz Tom
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  #4  
Old June 22nd 2006, 03:38
Bugat5speed Bugat5speed is offline
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Hi,

the 901, 911/01 and 914 gearboxes are engineered on the same basis. The 914 gearboxes have longer gears and are better for usage with big engines like yours. The 901 and 911/01 are good for well done type1 and smaller high revving type 4.
All these types stand torque of about 270 Nm without any problems. Have a lot of customers who drive cars with more than 200 PS with type 4 engines with 2.4 or 2.7 litres capacity.
If you plan to have more torque (what I don´t believe), then choose the early 915s (as mentioned above). This gearbox stands up to 350 Nm easily, but is bigger and weighs about 10 kg more than the 901-type. With my conversion parts you canplace the 915-gearbox in the same place as a type 1-gearbox. So, you won´t loose any space in the motor compartment.
The 901-types are quite easy to install with my conversion parts. There were several reports about my conversions in different magazines, like VW Speed, UltraVW, VW Tech, which show how easy it works.
For a 901 or a 911/01 you have to calculate about 700-1000 Euro to buy a not revised gearbox. The 914 can be bought for about 300-400 Euro. Be aware that in most cases the synchronisation of the 1st gear is completely worn out. Then synchro ring, dog teeth and the synchro sleeve have to be made new. These parts cost about 900 Euro (together) if you buy them from Porsche. If bearings are damaged or worn out, then mostly the gears are worn out too. But if not, then a set of the main bearings for theses gearboxes costs about 600 Euro.
Sometimes it´s easier and less expensive to buy a revised gearbox.
If you need further info, then please call me, or send me an e-mail to info@bugat5speed.de. Have a look on my site www.bugat5speed.de

Martin
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  #5  
Old June 27th 2006, 19:04
tdc911 tdc911 is offline
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Thanks for the info!
I think I will use the 914 1700 gearbox. I'm actually looking for one right now. Does anyone has one for sale or know a place where I can find one?

Friendly regards,

Tom
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  #6  
Old June 16th 2008, 13:16
vwdevotee vwdevotee is offline
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When people talk about using a 914 transmission, is that a transmission out of a Porsche 914, or a transmission code? If the former, do the 914-4 and 914-6 have the same gearbox, or not? Which is preferable? If the later, what models did the 914 gearbox come in? Thanks a heap.

Pax Christi
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  #7  
Old June 16th 2008, 14:54
vwdevotee vwdevotee is offline
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Also, what about a 912 transmission? Apparently they are 5 speed also. Are they any good? How hard to put in?
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  #8  
Old June 17th 2008, 15:08
Bugat5speed Bugat5speed is offline
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Hi,

the 914-gearbox is in fact out of a 914. The 914 is a type 901 adjusted for mid engine installation (flipped ring gear, different nosecone, other shift linkage inside).
The best 914 for a conversion for Beetle is the early 914 (mainly the 914 1.7-models). This type was used until 1972. Later came the sideshifter-model, which was easier to shift in the 914, but which is not that easy to convert than the 1.7. You have to change all the inside shift rods and need some extra parts of the 1.7 or from the 901.
The 914/6-gearbox is on one hand not easy to get, on the other hand it has much shorter ratios than the 914 from the 4-cylinder-models. The 6-cylinder engine was revving much higher than the old type 4, so ratios had to be shorter. 901s have short ratios also. 912s have 902-gearboxes (mainly). They are sometimes 4-speed and short geared also.

Martin
Bug @ 5-Speed
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  #9  
Old July 11th 2008, 06:11
SoCalGL SoCalGL is offline
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G50 with hydraulic clutch...hey i can dreamm...
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  #10  
Old September 10th 2008, 16:51
Clatter Clatter is offline
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923 gearbox.
Out of 76 912E only....
A 915 gearbox, basically, but witha few differences....
Close ratio, designed specifically for type4 power.
No need for clutch conversion parts.

Rare as hen's teeth.

found one on the samba for 900.
It cost another $900 to have it gone through.
pluse $200 for the unobtanium throwout bearing.
But i get to use the regular 228 clutch.
And the gearing should be ideal.
Another car that had the same gearing was the 76 Carrera 2.7.
they are usually scooped up by wealthy 911 track guys who want the gears out of them...
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  #11  
Old September 21st 2008, 15:37
Bruce2 Bruce2 is offline
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Quote:
Originally Posted by wrenchnride247 View Post
If you "drag race start" any stock Porsche, or VW tranny in first gear it will not last long.
Not entirely true. The early 10 tooth first gear in a VW trans isn't very strong, but the later 9 tooth is more than enough for any street car. I've seen them survive 300+hp with drag slicks.
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  #12  
Old September 21st 2008, 16:22
vwdevotee vwdevotee is offline
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For how long though? The abuse of drag racing them will significantly shorten any transmissions life.
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