actually the title of this thread is 'FOUR wheel drive civic', of which of course there already exist- the civic rti, rtx, the integra xsi, xi-4wd, etc etc.
However, if the topic is how to build an AWD civic- not to oversimplify this, but there would be no need to have $XX,000 in custom engineered and fabricated gearsets, helicals, outer cases, etc.
The B-series crv 'transfer' case is not exactly a transfer case per se- there are no internal clutching mechanisms, it's just a 90* drive. The clutching is all done in the 'dual-pump' rear end. On the other hand, the elusive JDM/Euro-spec 4WD civics and integras as well as 4th gen 4wd civic wagons are just the opposite- a conventional 4wd transfer case and rear end. All that would really have to be done is to fit the 4wd civic/teg fuel tank (or custom equivalent) and rear end, axles, etc along with a B-series driveline setup with a crv trans and transfer case. It theoretically could be done with 97% factory Honda parts. The only component that would have to be custom is some sort of viscous clutch would have to be fit somewhere between the transfer case and rear end to allow for differentiation between front and rear.
Anyone?