[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

83 Turbo Quattro Coupe (comma more power)

   Hey, any motorheads out there?

That is a rhetorical question, I presume . . .

   I just purchaced an 83 turbo quattro coupe in great condition, but as seems
   to be the case these days, my quest for more horsepower always seems to
   outweigh my quest for sensibility.  I was thinking that a 20V head would be 
   the way to go.  Has anyone out there attempted this? (Is it even possible?)

I also fell for that scam . . . so far all my money's been spent flatbedding
the eff'ing thing to conveniently-located dealers (well, I don't really count
the second time (AZ) against it, because it was follow-up flatbedding from the
first time (CA) dealers destructive twisting of the fuel-pump wiring harness;
and the last time was flatbedding it *FROM* a local dealer (Pass Weitz in
Burlington, MA who took a semi-running Audi and turned it into a solidly
non-running Audi) to a local "Porsche" mechanic recommended to me by a friend
in the Porshce Club) trying to keep it running... but hey, it got up to 6
months between $500 bills (left rear wheel bearing, plus a few odds'n'ends
"as long as I was there").


...on the power side, my only offering (other than give John Buffum lots of
money, and I'm sure he'll give you back a truly insane car!) is one person
I talked to (actually, he saw me out front working on mine, and stopped
by to chat about his) had played with his. He put an "APC" (??) unit from
a Saab on his engine. This gave him adjustable boost control as well as
a knock sensor to automatically back off the excessive boost (Note: the
'83 has a Hitachi engine computer with no knock sensor nor boost control;
I'm not sure if it controls engine [ignition] advance, but I do know that
when it gets onery, it shuts the whole engine down - whether by shutting
off the fuel pump or ignition (both I suspect, as both "come out of" the
computer) or both I don't know). He runs the engine at a nominal 14psi of
boost (er, exuse me, one bar of boost). Sweet engine! Still zero power
under 3,000rpm, but boy that 3,000 to 6,000 band was fun. He said he did
not have to modify the fuel system (i.e., stock fuel system can deliver
sufficient fuel to actually make power), and normal "high octane" premium
(e.g., 92/93 Shell/Mobil/etc) worked fine with almost no knocking ever -
very occaisionally his APC unit would back off the boost a coupla psi's,
but it generally held solid at 14psi or so until *he* backed off due to
lack of road, desire to keep drivers license, etc. I think he was also
running sans cat, but am not sure.

I would suggest that playing with the boost, and possibly cams would be a
more productive power play than trying a 20V head (you'll still be running
7-or-so:1 compression!). Possibly higher-compression pistons (say 8:1 or
maybe even 8.5:1) might help the bottom end power. The European version of
the car was rated 200hp (US version 160 pissante hp), so there is "easily"
another reliable 40 hp lurking there somewhere, but noone has ever been
able to say what the real difference 'tween European and American spec en-
gines was (certainly the cat, possibly different cam, it seems unlikely that
Audi would run different crank/pistons/valves, also unlikely (???) different
fuel system).

While I drool at the thought of an S4's 20V turbo engine (everything I have
read suggests that after 10 years Audi has finally caught up to Mitsubishi
in making Turbo engines "work" well - my '85 Mirage Turbo builds solid boost
at 2,000 and behaves for all the world just like a "hot" normally-aspirated
engine with a 2,000rpm to 5,000rpm power band falling off by 6,000rpm), it
would be new wiring harness, lots of plumbing (I suspect the cooling system
is probably the only thing that would more-or-less fit, unless some other
piece of plumbing interferes!), and I suspect a major headache! Does anyone
know if the (e.g.,) S4 and other "later/current" Audis use the same com-
bined power-steering/braking high-pressure-hydraulic system, or would that
have to be retrofit, or ??? If you *must* do an engine swap, why not con-
sider say a nice reliable easy-to-get (and cheap too) 300ZX turbo motor?
It probably wouldn't be any harder overall to graft it in, and would be re-
liable besides! (I'm only *half* joking, folks! While I suspect that over-
all Audis are probably "better engineered and more reliable" than, say, GM
Chrysler etc., they have a longs ways to go to catch up to, for example,
Mitsubishi...my somewhat embittered $.02' worth...)

Question for you re "stock" power: my car has almost no power below 3,000
rpm (low compression, boost starts at about 3,000 and builds quickly past
that, but a crippled turtle will still beat it off the line), but develops
power quickly and steadily past 3,000 to about 4,200 or so, where power
falls off rapidly until by 5,000 rpm it is basically doing nothing more
(e.g., in third gear on level highway it will not make redline!). I've
had dealers all across the country tell me the car is running fine. Does
your "stock" engine behave similarly, or does it keep pulling past 4,500rpm?
One friend (with a Saab) suggested a clogged catalytic converter, but the
mechanic whom I now trust said probably not, something else is probably
wrong. Any experiences/hints/etc. from y'all?