[V8] V8 engine swap to C4 Avant

[Acadian Lion]

At the great risk of inciting a few more death threats because I am 
exploring the possibility of replacing the 2.8 V6 and 4HPFLA 
transmission in my '94 100CS with a 3.6 V8 and its 4HP24A automatic 
transmission, I have some new information about possible issues with the 
swap.  So far to my knowledge no one has made a swap like this one, or 
more precisely, I have not FOUND an example of this swap. There are 
many, many installations of V8 engines into the C4 Chassis cars, but all 
seem to have one thing in common:  they ALL involve the changing of the 
transmission type to either a five or six speed manual. ALL of the work 
has been very time consuming and very expensive, because the differences 
in the transmissions presents enormous challenges that are either 
daunting to even the best of amateur mechanics and VERY expensive to the 
person who hires a pro to do it.

I get all of that. But the swap of a V8 into the engine bay of a C4 car 
isn't the nightmare space wise that installing one into a Type 44 car, 
like a 200, say.  The V8 WILL fit with one detail that could really be 
problematic. The unknown answer to the big question I have right now, is 
will the 4HP24A transmission be a direct fit.  IS the front wheel drive 
shaft placement direct to the placement of the front wheel?  The best 
answer to the question is probably to find out the dimensions of the 
transmission case.

I suppose another question is will a 4HPFLA transmission bolt to either 
the 3.6 or 4.2 V8 engines?  That might solve the problem. I know that 
there are engine mounts readily available for the installation ($200 to 
me right now, if I want them). But the question is how well or how 
difficult will be the mating of the front wheel drive components of the 
Quattro system.

Another issue that has been pointed out to me is the presence of the 
drivers side distributor and the brake booster.  There is insufficient 
room to DO anything with the distributor once it is there, UNLESS the 
brake booster can be moved in some fashion.

Now, there is yet another workaround for that, and that is to use a V8 
from a later car, one with coil packs instead of distributors.  But 
again comes the question, "which transmission"?  I have a significant 
resistance to the Tiptronic transmission because of their reputation for 
grenading at around 100,000 miles or before, and their reputation for 
oil leaks is pretty strong, also.  I do not believe the 4HPFLA 
transmssion will mount at all, nor do I fantasize about that 
transmission taking the torque of the larger (or maybe any) V8 engine.  
I also have a sort of aversion to the idea of using coil packs also, 
chiefly because of stories I have read of coil pack failures in later 
model Audi engines in general.

I am waiting to hear back from ZF about the transmission dimensions and 
data that will give me a bit more information.  On the surface, I 
"think" the engine cases are the same generally because the 4HP24A 
transmission was used at the factory for the Euro C4 V8 which was never 
imported.

In the end I doubt this will get done at all, but at least when I decide 
to send the old wagon to the crusher I'll know I have given all the 
alternatives a chance.  And for anyone who might suggest it, yes, I'd 
love to have an S6, IF I could find a one owner example with 80,000 
miles that had EVERY service record from new, AND preferably, had just 
had the Tiptronic ovrhauled and the timing belt service done.  As of 
right now, IF such a car exists, it would cost more than the swap of the 
V8 into my old wagon and it would probably still have the typical 80,000 
mile engine leaks.

Roger