80q MC turbo engine swap information

[be_larson at access-4-free.com]

Turbo conversion 1988 Audi 80 quattro/MC engine
Brian Larson-Saint Paul MN

Disclaimer, I take no responsibility for the correctness of
the information listed below, please check your own
information and schematics before ruining something!  Before
following any advice from the web, please double check all
information you find.

First of all thanks to the guys who have done these swaps
before me, and taken the time to share your information.
The info you guys posted on the web was inspiritational, and
helped with a lot of the technical details.  Thanks to Dave
Close, Pat Martin, Javad Shadzi, Marc Swanson, Nate Stewart,
Scott Hare, Martin Pajak, Mark Chang, Brian Bressler, Scott
Mockry, and others I am sure I forgot.

I did this swap to make the car a lot faster and more fun to
drive, a fun inexpensive commuter car.  This swap was done
to be more budget conscious than a lot of the other ones you
see on the Internet, but I tried to replace all of the
necessary parts that are hard to get too later.

The car is a 1988 Audi 80q, with 190,000 miles that I
purchased with 182,000 miles for $600 two years ago, it had
a bad starter and a clunky suspension, and the check engine
light was constantly lit.  During the time I was driving it
I replaced the wheel bearings, rear struts, all tie rod
ends, all strut mounts, lower bushings, and lower ball
joints to the tune of about $700 more dollars.

The donor motor I bought was out of a 1990 Audi 200 turbo
(mc-2 with k24 turbo) with 152,000 miles that I paid $200
for and pulled myself, and I sold the wiring harness,
computer, and other items from this unit for $300, so I
guess the motor was free.  Out of one of my old parts cars I
took out a mc-1 wiring harness and mac11 ecu, and installed
a QLCC chip in it.  When the motor was out of the car I put
new timing belt, idler bearing, water pump, crank and cam
seals, and 80 oil pan and baffle on it.  Also, I swapped the
mounting brackets over from the Audi 80 quattro motor,
including modifying the front one to clear the turbo by
cutting off the AC mount. Also, since I am using the stock
80q transmission, I had to swap one larger transmission
alignment dowel over from the 80q motor to allow the 80q
transmission to mount to the 200 motor.  I used a 5kt
throttle body and cable bracket.

Clutch and flywheel; I modified the 80q flywheel by
machining 2.4 pounds off the back, adding the 5kt timing
pin, and had it balanced and resurfaced.  The modifications
to my flywheel are detailed on Newtsplace.com, this worked
fine.  The clutch parts I used are 1988 80q pressure plate
$112, 1990 coupe quattro 20v clutch disk $141, 1988 80 q
release bearing $40, 80q pilot bearing $8, or $301 for the
complete clutch assembly.  You could probably duplicate my
flywheel modifications for $150 if you cannot machine it
yourself.

Oil cooler, I used a 1989 Audi 100 quattro oil cooler (88
5ks cars have these too) and lines without modification, and
welded a mount under the passenger frame rail.  A friend of
mine did this to his 1984 4ktq first, and it worked so well
I used it also.  $12 from the u-pull yard!

Intake, I used a urq airbox top and intake hat, and 5ktq
intercooler hoses, I was lucky enough to find the urq pieces
for $120, but this is the exception to the rule, the going
rate seems to be more than that.  I drilled and tapped the
intake for the air temp sensor, to open up my intercooler
upgrade options in the future. I did the cut and splice
routine for the throttle cable, in retrospect I would
probably cut the pedal end off of a 5ktq cable, and thread
it though the 80q sheath ala Javad.

Intercooler, I used the stock 5ktq intercooler and cut away
enough core support (upper and lower and headlight riser
also) to get it to fit, and removed the center hood latch, 2
are enough in my opinion.  I also had to grind away the
backside of the grill in several places to get it to come
close to looking stock.  I removed the secondary radiator
and looped the lines with a ¾” to 1” straight fitting
from the hardware store, a poor mans 4kq radiator.

Exhaust, 200 turbo automatic downpipe, cut 1.5” after the
wastegate, and welded custom back from there into the 80q
exhaust.  For a rough idea of what I did, just angle the
pipe in where you cut it to gain enough subframe clearance.
I wrapped the downpipe with header wrap because it is within
¼” of the painted frame rail and I would recommend
everyone else does this too.

Body, Battery box removed and battery relocated to trunk
using 5ktq battery cable run through car on passenger side.
Passenger side tie rod bent with a torch to clear wastegate
and body.  It was necessary to bend my tie rod in two places
to get it to clear everything.
For the lower grill, I ground away the back side of the
grill with a 4" angle grinder to make it totally open to air
entry so the oil cooler could get some air.  I added an
analog boost gauge and a digital fuel mixture gauge in a
custom panel where the ashtray used to be.  I just cannot do
the “Boy Racer” gauges on the A pillar, man it sucks to
grow up!  I put in new 80q transmission mounts, and new 5ktq
motor mounts as long as it was apart.  I removed the AC, as
it did not work, the condenser was junk, the turbo is in the
way, and lighter is faster.

Wiring information, for my swap, the red 5ktq harness was
the only critical one.  Plug everything under the hood in,
and hook up the necessary wires under the dash.  I installed
the red harness in the 80q after the turbo motor was in, and
it worked well, there is enough room (with the heater box
out) to maneuver it into place.
Mac 11 pin		5kt color(at t14b)	80/90 color		80/90 fusebox
31			Y			Br/G			Ila
21			Br/G			G/V			Bs
1			Bl/w- Bk		-			B87f
8,3,19			Bl/Bk			-			87a
Power to computer “I15” is on when key is on “on” or
“start” condition, 2.5 Bk to Bl/r pin 35.  (I actually
got this power from the old coil power, which is hooked up
to the coil distribution block).
The codes flash fine, and the wiring seems to work great so
far.  I used the stock 80 oil pressure warning system, and
charging/starting system, and cooling fan switches.  I hid
the ECU behind the heater box, it fits in the stock location
with the bracket removed.

As of right now, I have no secondary water pump on the
turbocharger, and no injector cooling shroud or fan.  I
might add these later if necessary.  This is my 5th
turbocharged car, and I do not feel the afterrun pump is
necessary as long as the turbo is allowed to cool down for
30 seconds after a hard run, and our climate is pretty
moderate 350 days per year.

Possible future projects on this car include plans to
upgrade to Megasquirt EFI, to be able to uncork the intake
side, and support approximately 300 crank horsepower of fuel
(15-18 psi ?), while running all factory boost and timing
controls, and retaining the ability to flash trouble codes
and troubleshoot.

I had a few teething issues after getting the car running, a
bad WOT switch harness which I replaced with another plug,
and a bad warm up regulator.  After fixing those things, the
car starts and runs well.

It is a fun car, I look forward to driving it for a long
time!