From: [email protected]

Subject: Turbo MC in 80q...My experiences (long)

I'm sure all of you out there who have ever walked through a junkyard have seen turbo motors in 5K series cars. If you were like me, you fantasized about the extra horsepower and performance that the swap would give a small bodied Audi Q. Well I can testify that the transplant has completely lived up to the fantasy (with the exception of a few nightmare problems that I ran into).

I actually bought my 88 80q with this swap in mind. I liked the fairly modern (not to mention stealth) styling of the 80/90 series cars. I decided on an 80q because of the lower weight and less complexity than the 90 cars (80 series have no leather interior or ABS). Before starting the swap, I wanted to make sure that the chassis was up to the increase in HP. I went with Eibach/Koni sport. All new bushings and rubber mounts. Fabricated 3/4" rear anti-roll bar and a Tilton adjustable brake proportioning valve as well as upgraded pads. (4 pot calipers will be the next project). I enjoyed the car for about a year with the stock motor...great snowboarding car but definitely low on power. This post will illustrate how I did my swap. There are always alternate routes, and hindsight is 20/20, but for the low amount of money I spent, I'm extremely happy with the results. Re-locate the battery. This was needed to clear the wastegate. It also really helps the balance of the car. I removed the whole battery box where it is spot welded to the body. The battery fits well in the pass. side trunk well. I found a battery hold down at the junkyard, drilled 2 holes in the 80 and bolted it down. I ran the cable up the pass. side where the carpet meets the plastic cover. It fits under the cover. Then I drilled a hole under the A/C unit in the firewall. Use a good rubber grommet. Then connect to a junction block and use to power all the systems.

Find an MC. I found a good running cheap 86 CS with 75,000 miles and great compression. It was nice to have a running car, as I saved the costs of towing. Also, I wanted to know what, if anything was wrong with the engine. I was able to do a compression test and pull the codes BEFORE I bought it. DO NOT attempt to perform the swap on an engine that doesn't run. You will introduce so many new variables during the swap that you won't know what you caused or what was pre-existing.

Prepare to remove the MC. I worked on the 5K for about 2 weekends before I was ready to pull the motor. I had it steam cleaned. Then I labled EVERYTHING. A running car also allowed me to experiment with disconnecting different harnesses to determine which ones were vital. I found in my car the red and the yellow taped harnesses are critical. Label all connections from these as a starting point. Then begin carefully removing the harnesses. Don't leave the coolant after-run harness and equipment behind.

Pull the turbo motor. Hoist is recommended, but not necessary. You can pull the motor straight out the front after removing the body front end pieces. Once I had it out, I did the t-belt, w-pump etc. Clean all the nooks and crannys. Remove the auto tranny starter ring and pilot bushing. Use a slide hammer for this. Remove the downpipe, alternator and A/C compressor.

Clutch: Major pain! You 4kt guys have it easy as your clutches are interchangeable with 5k. 80/90 series clutches are not compatable. I found out the hard way. Learn from my mistakes. The transmission input shaft is larger on the 80 than the 5k. There are also offset and pilot bearing issues to deal with. I ended up using the 80 flywheel, a new 80 pressure plate, and a friction disk from a 90-91 Coupe Q! This actually worked out well, as the Coupe disk has the correct splines and the 240mm diameter that the turbo needs (especially after increasing the boost). The stock 80 pressure plate also has 240mm diameter (odd, because the stock 80 disk is 228mm.) I then had to have the flywheel surfaced to at least 240mm of area. The final step is to have a Hall ignition timing dowel installed in the flywheel. I measured very carefully based on where the original auto tranny starter ring had it's timing dowel. You will need to have about 1/4" of shoulder machined off of the 80 flywheel so you can install the Hall pin deep enough toward the pilot bearing. Have the flywheel re-balanced after all the surgery. Be sure to re-adjust the Hall pick-up unit clearance. There might be a flywheel out there that has the Hall pin and compatibility with the MC as well as the 80q tranny. Possibly a Coupe Q or S4? I didn't even look into it though as I couldn't confirm what would work, and I was afraid of the cost. My solution worked great for only abut $130 in machine work. (The key component, the Coupe clutch disk, was $240.00! Ouch. I didn't know a disk could cost that much! I feel for you Coupe guys. Is that typical?)

Remove the 80 motor. I pulled mine out the front of the car with a floor jack. With the motor out I was able to clean up the engine bay and repaint the section where the battery box was. Don't break your plastic radiator like I did. (oh well, I can probably use the extra cooling from the new one.) Replace the pass. side tie rod with one that clears the wastegate. I ordered one from 2bennett. They wouldn't modify a used one...they would only bend a new one. Took about 5 days. No complaints.

Pre-wire the car. You will need to drill about a 1" hole in the firewall near where the A/C plumbing goes into the interior. This is for the pass. side wiring harness. If you remove your A/C, you can probably feed the wires through the remaining holes and wouldn't need to drill. I then removed all the wiring that was used for the 80 engine. The only wires I kept (that were in the harness with the CIS wires) were for the oil pressure system, the cooling after-run system and brake and coolant reservoir sensors. I had to pull the harness through, separate these required wires, then re tape them as a small seperate harness. Finally, install the MC harness in the 80. You need to feed at least the pass. side harness through, as it is tough to do with easy access. I can't imagine doing it with an engine in the way. The driver side harness feeds through the stock hole with no problems.

Install the MC. You should use a hoist...very difficult to steady the I-5 on a floor jack during installation! Lower it down and slide it onto the gearbox. Don't tighten the motor mounts yet, as you will need to lift the engine to fit and install the downpipe. Once the motor is in, you can start attaching wires exactly as you had labeled them. Swap all parts that the 80 chassis needs like the thermostat cover, special engine/gearbox connectorbushings, engine mounts, etc. The passenger side mount bracket can be left on, but you must use the driver's side from the 80 motor.

Wire the car. You will need diagrams for both cars. I used a Bentley for the 80q and a Chilton for the 5k that had Bentley wiring reproductions ($10 at Pep Boys). I didn't find it necessary to remove the 80 dash...just take out the instrument cluster. Snapping on connectors is the easy and fun part. Install the coil and wastegate control unit. I slightly modified the bracket so that these 2 could be mounted together using stock mounting studs. I used a heavy duty junction box from the 5K to connect my battery cable to the starter cable. The computer will just fit in the stock computer mount behind the air conditioner (remove the spring metal clamp from inside the plastic box and the box will slide right in...like it was made for it!) I then fabricated some brackets to hold the computer in place. The difficulty is in connecting MC wires to the 80 fusebox. The good thing is that the fuseboxes appear identical. One critical connection is the Black harness plug "B" (schwarz) that plugs into the underside of the box. I had pulled the same connector from the MC harness intact. I then removed each wire end from the MC plug and placed it in the 80 plug (after removing it's matching wire). There are additional wires in the 80 plug, so you can't just swap plugs. I found the wires were similar, but not exact color matches. Double check EVERY connection with both diagrams. After that is connected, another wire goes to the ign. switch (solder/splice) and another plugs in under the fuel pump. I can't remember the colors, but I had them clearly marked. Other connections include the temp gauge, tach and check engine light. These are straight forward. Just determine the color from the 80 dash, the corresponding color from the MC harness, and splice. I used solder and shrink wrap, just to be on the safe side. Once again...double check all connections. You don't want to blow up that precious computer.

Exhaust. The stock down pipe didn't fit. I cut mine to almost the correct length to meet up with the 80 cat. I then had it bent toward the center of the car after the wastegate connection to avoid contact with the sub-frame. A lot of trial and error. The clearance was so tight that I had to jack the motor up to get the downpipe in. After getting the correct angle to meet up with the 80 cat, I welded the flared end of the 5K downpipe on after placing the floating clamp over the pipe.

Airbox. Either cheap and difficult or expensive and easy. There isn't enough room to run the stock 5K airbox/rubber airduct and metal intake tube. Urq airbox top and air duct are both available...about $400.00 new for both. I chose difficult and cheap. I took an airbox top from a 4k. I cut the top section off, rotated it 180 degrees, and glued it back together. Turning the metering head around gives you the clearance needed, as it eliminates the metal intake tube. It also gives the added bonus of shorter intake lengths and less lag. This took some work. I used marine epoxy and fiberglass to stick it together and make it air tight. I only used large sections of glass. They must be custom cut for each section of the box. This is because nothing seems to stick to injection molded plastic very well. I didn't want a small chunk of glass working it's way through the intake system. The epoxy sticks pretty well...you really have to pull on it to separate it. I sandwiched the plastic between epoxy on both sides. So far it is holding up fine. I plan to keep an eye on this. If I see a problem, I'll buy an Urq box top. Place the metering head on the airbox with a new gasket. I used a rubber air duct from a Rabbit. It's a little smaller, but it fits. I then fabricated a pipe from the Rabbit duct to the turbo. All the VW guys will recognize the Rabbit duct, and the Audi guys might snicker, but it works great. The most difficult part was cutting away sheet metal from the hood latch vert. support pillar. This is needed to allow the turbo inlet pipe clearance. The hood latch torsion spring gets sacrificed, but a small coil spring easily takes it's place. I then re-enforced the support pillar with fiber and epoxy...strong and light.

Fuel lines. Since I turned the metering head around, the fuel distributor to injector line configuration had to change. I looped mine back around so that they attach from the direction of the fender. There is plenty of line length, so you won't kink the lines. The rest is just a matter of finding the correct size and length line at the junkyard for the application you need. There are many different CIS cars out there with different configurations. It took about 3 trips to the junkyards to mix and match what I needed.

Accelerator linkage. I was able to use the stock cable. I first removed the head mounted linkage pivot bracket and the 2 link rods attached...No longer needed. I then fabricated a bracket to hold the 80 cable/sleeve and to allow ajustability. This is attached to the bracket that supports the rubber cruise control unit and faces toward the pass. side strut. I then removed the linkage pivot that bolts to the rear of the intake manifold and modified it to accept an Audi cable guide end....that's the plastic device that holds the end of the cable onto the throttle body on the 80. I left the rod from the manifold pivot to the throttle body intact. Be careful not to allow the new linkage action to hit the ISV that is bolted next to the pivot.

Oil Cooler. Tight fit. There is a support tube between the frame and the pass. side fender. This works well to hang the cooler from. I angled mine so it fits inside the bumper cover. A cool air duct is then needed between the cooler and the bumper opening. Holes in the front of the wheel well help with air flow.

Intercooler. Very tight fit! It will fit behind the grill, but with major mods. The aux. H2O cooler must go away or be re-located. Next, the hood latch comes off. I then removed the vert. latch support piece that is spot welded to the horiz. support. I re-enforced the horiz. piece with fiber and epoxy. I kept shaving off metal until it no longer contacted the intercooler. 2 rubber mount brackets need to be fabricated to hold the intercooler. I bolted 1 on the large lower cross beam under the headlight. The other bolted to the underside of the horiz. support piece. The grill needed to have a little plastic shaved off the back to clear the intercooler. Since I removed the vert. support, the painted trim piece that fills the gap between the bumper and the headlights needs a new support. Another bracket connects it to the large lower cross beam. It all barely fits together, yet looks stock. The last step will be to find a place for a safety latch. This shouldn't be too difficult.

After-run systems. Easier than I expected. The relay was bad on my 5k system. So instead of replacing it, I ran my H2O pump off the 80 after-run system. It has an 8 min. fail safe timer. I wired it from the timer relay red/white wire. The low speed fan was already pre-wired. I then connected the original 80 thermoswitch (air activated) wires to the MC after-run thermoswitch (coolant activated). The injector cooling system was taken intact from the 5K. Brackets are needed to hold the water pump and the fan. I mounted the pump to the brake booster bracket. You need to get creative with the coolant hoses. I used the stock 80 head to rad. hose, cut it in half and fabricated a T line for the coolant pump. The fan is now bolted to the head where the accelerator linkage bracket was (the bracket for this was time consuming to fab. and weld). Test the fan by grounding the wire. Test the pump by connecting the 2 thermoswitch wires together. (make sure the ign. had been on recently or it won't work)

Start the car. Should start up almost immediately. If not, pull the codes. My first try ended with a loud repeating metal on metal sound. That was the hall ignition pin being bent to a 45 degree angle by the starter over-run clutch. My mistake. Never would have anticipated it. That's how I learned that 1/4 inch of flywheel material must be machined! So after pulling the gearbox and flywheel, machining, re-pinning and re-installing (whew!), the motor started on the first try. Run up to temp. and the fan should come on. I had to track down a few annoying problems, but all seems O.K.. The car feels really strong. I'll be upgrading the boost next, but it is very enjoyable for now. It really transforms the car.

My project took about 5 months of down time, working every weekend. Much of that was re-doing things I screwed up the first time. But even knowing what I know now, it would still take at least 3 months of weekend work. It takes time to fabricate custom parts, if you care about the final result. It was a very enjoyable project. I hope my errors will help the next person enjoy the project even more.

Cost breakdown (approx.):

MC $1200

T-belt, w-pump etc. $100

Clutch assembly $350

Flywheel mods $130

Tie Rod $110

Mounts $120

Sub-frame bushings $120

Control arm bushings $40

Supplies $100

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Total $2270

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Dave Close

Oakland, CA

88 Audi 80 Quattro Turbo

74 Lotus Europa Special