[V8] This may be too far out even for me....

[Roger M. Woodbury]

I'm getting mixed reactions so far. To my knowledge, the ONLY V8/C4 
swaps that have been made involve making "vroom-vroom" cars, installing 
manual transmissions into cars that either were never designed to have 
one, or involved hunting and finding part all over the globe (or at 
least in Germany) for cars more than a decade out of production.  
Correct me with specific examples if I am wrong.

Audi built a C4 S6 with 4.2 V8 in 1995.  The engine and transmission in 
that car was the same engine and ZF4HP24A transmission used in the 
earlier V8's. So, in theory, the engine and transmission will both fit 
earlier C4 cars, probably with fabrication of transmission mounts, 
perhaps. BUT the transmission in the C4 100CS is the ZF4HPFLA, and I 
suspect the only difference between that transmission and the 4HP24A is 
internal, specific for the V6 engine.

Scott, with all due respect to your knowledge and expertise, your 
concept of "fully depreciated" is vastly different from mine.  The 
allroad is a car with which I have had a fascination for since it was 
introduced.  My wife and I sat in a beautiful example on the dealer's 
lot in 2004 when we began to think about the eventuality of replacing 
the 100, and even then, gave a bit of thought to going to one car (we 
had three vehicles at that time). In the end that afternoon we passed on 
that new allroad. There were several reasons, only one was cost.  The 
real killer was a discussion I had with the service manager whom I had 
known for fifteen years or so at that point.  His advise was to run, not 
walk away from that car. He said it was a GREAT vehicle to lease, with 
full maintenance plan for three or so years, but run away afterward. He 
cited known or anticipated difficulties with transmission and "engine" 
issues he didn't specify.

Now in retrospect I have learned that:  the 2.7TT engine is a grenade 
waiting to go off. The turbos WILL fail, and likely before 100,000 
miles.  That requires an engine removal and VERY expensive new turbos. 
Buying the cheap Chinese knockoffs will not work well because they are 
about a millimeter or tow off in each direction. So turbos are a very 
expensive proposition. Oh, but wait:  I havne't seen one myself, but I 
understand that the starter motor is buried beneath the left side turbo 
installation, too.  Another engine removal should the starter motor go 
out, and there is more:  The TT engine is an Audi joke, in my opinion.  
I have owned two Audi turbo-engined cars on which I accumulated a LOT of 
trouble free miles.  But a NEW turbo car?  Not in this house, even if 
the car was free.

Now the V8 allroad is THE car that I thought perfect for anything we 
might want to deal with into the future.  Then I read about the chains 
that make the motor work....THREE of them?  and Chain tensioners and 
worst of all, the PLASTIC guides.  Well none of that really bothers me, 
having lived with V8 timing belts and all. EXCEPT of course, all those 
chains, guides, and tensioners (which aren't cheap just by themselves), 
are jammed back against the firewall and ANY service on them requires 
yanking the engine.  I saw a list for the entire chain 
guide/tensioner/chain rebuild and it passed eight grand. NO WONDER the 
things are worth NOTHING on the used car market. Either the engines 
already have developed the "chain guide death rattle" and the seller 
KNOWS what is going to happen, or the engine has already grenaded (I 
know of one in New England right now like that), and the cost of the 
engine overhaul is unknown, but HUGE.  (The air suspension on the car 
isn't really an issue. I can replace the airsprings in my garage if I 
had to. I won't, but I could.).  So the V8 allroad is, in my opinion, 
yet another Teutonic joke.

So, I have in hand a decent, if high mile 100.  It needs the things I 
have discussed before, the cost of some of which I have already.  I 
"could" just reseal the V6 and it might well thunder along for another 
dozen years. Bear in mind, our intended use of the car will yield 
perhaps seven or eight thousand miles per year, so long as I have the 
V8.  But the reseal in the engine requires pulling it out, and probably 
the transmission also.  I would agree that THAT project is arguably not 
worth doing. BUT if it was possible to install more power with few 
downsides other than front end cost, it might be worth it.  With the 
added beneifit of having a really and truly fully depreciated vehicle 
that is otherwise a known quantity.

and the headlights in my 100 are infinitely better than the plastic 
shades Audi has stuck on all its cars since 2000.

R


On 1/19/2017 8:04 AM, Scott Justusson wrote:
> Let me put the nail in the coffin for you Roger.  I am a self 
> proclaimed expert on what you are/were considering.  I own a 300k mile 
> A6 (still running, going to the yard), I completed a C4 A6q Avant v8 
> swap and maintained it for a guy for almost 10 years, I have 
> personally installed 2 PES superchargers on the 2.8, and I own 2 Audi 
> v8s. You are plain wasting your time.  Get the allroad as someone 
> suggests, it solves everything you wish to do, with a fraction of the 
> headaches.  Yes, the 3.6 and 4.2 *fit* in the C4, but it is a 
> shoehorn, a really really really tight shoehorn.  To not get the 
> factory version means every single thing you do is 1off.  Ask me how I 
> know.  The ingolsataudi guy  did it too, read his build thread 
> (actually don't, it is not worth it).  And that car in the words of 
> the owner of the one I maintained who personally road in it, was 
> 'rough' at best.
>
> An A6 meticulously maintained at 300k should not receive 'another' 
> refresh IMO, it is far cheaper to buy another.  As you contemplate 
> desire for horsepower, it is not with what you have that makes any 
> sense , it's what Audi has waiting for you, fully depreciated.  The 
> allroad 4.2 is the car you desire, without the 1off dump in the toilet 
> of investment dollars.
>
> I have been on the v8 list since inception.  I know you are not a 
> mechanic, you are loyal to one.  That seals the deal, forget it. 
>  Don't read how it was done, read up on the market price for a 
> pristine 4.2 v8 allroad.  The rest is dreamy chatter that makes me 
> think you need to seek warm weather and sunshine really soon.
>
> Cheers
>
> SJ
>
>     Well, as I have already said, it may turn out to be an exercise in
>     frustration. I suspect you are correct in that the ZF transmission
>     might well be too wide at the bell housing to fit, or perhaps too
>     long. It also would make the electric control for the rear axle
>     unnecessary making replacement of the rear axle an unnecessary
>     step. In the end the ideal situation would be to mate a 3.6 with
>     the existing 100 transmission. I might point out here that the
>     only goals in this entire thread is to 1) extend the useful life
>     of the 100 and 2) add those seventy horsepower that I have thought
>     the car really, really needed. I know there is no way to get the
>     added power from the 2.8 V6, at least none that I have found out
>     about and I have been looking 
>
>