Superbeetle 4X4 with carrera 4 gearbox
 

hello
My project i want upgrade my 1303 in four wheels drive with 911 carrera 4 gearbox
Btu i don't kown if it's possible and i want kown the problem for the front transmission

With enough time and money anything is possible. For the porsche swap you would need the complete drive train, tranny, front-rear drive shaft, front diff, front steering knuckles, front axles, and all the brake assemblies to start with. Then all you have to do is make them work on a super beetle with some crafty fabrication. It won't be cheap or easy, but it is possible.

Or use a mass of Subaru parts like the front legs rear diff (flipped and in the front), centre prop, Subaru gearbox with reverse crown wheel and pinion conversion and the an EJ20 Turbo motor.

I've thought long and hard about a 4WD conversion and came to the conclusion that a new spine and a chassis renewal forward of the Nap hat was necessary with the obligatory 944 turbo rear end on coil overs and uniball. Then of course there were the 4wd Supers in European Rallycross in '80s..............

another way could involve Golf knuckles, with the porsche trans/dif. or a cheaper option could be a vanagon syncro trans/front dif.

still lots and lots of fab work, but I'd love to see it done. biggest problem I see is no place for the driveshaft to run, and no place to put the front dif.

frame head and tunnel will have to be removed, rear torsion tube most likley in the way also, so a new frame would need to be built. so now it needs a cage...

Forget 964 C4 as they're electrconically controlled and have a solid tube connecting the gearbox to the front diff and the wheelbase is too far difference to work on a bug.
993 is a simpler system but still has the tube connecting the gearbox to the front diff.
996 uses the same idea of a Viscous Coupling 4WD but has a seperate propshaft so you can lengthen or shorten it as you wish. The problem with this setup is that the engine/gearbox bolt pattern is different. In fact it's the same as the Audi 5 Cyl, V6 and V8... so you could put something different in there if you wanted.
The only setup that would bolt up to an aircooled engine and has a seperate propshaft is from a 996 Turbo... very expensive but you'll never break it (as they come wiith 400bhp stock and can handle anything over 800bhp!).

MG

from what i rememeber of the rallycross cars some of the ran a syncro gearbox out of a t25. depends how much power your wanting to put through this as to what gearbox you end up with as no point useing a syncro gearbox if you want 400bhp.
as your asking about porsche boxes i guess you have 400bhp so need a gearbox that can take that sort of power.
i have thought of useing the golf front struts as well as the knuckle will fit on to the 2 bolt struts and if you use a kercher ball joint then it will fit the tca so thats pretty esay to do. getting the diff in the front is another matter :lol; i think it would be esayer to build a space frame chassis to mount it all in and pout the beetle body over the top. if i was doing that then it would have double wishbone suspension all round any way.
cheers rob