Help Needed 1991 Audi 90 (7A) Swap

[Audi_UR]

Hello guys, I'm new to this forum, figured i would ask for help on my project. Possibly one of you guys can give me some pointers or guide lines to follow on this build.
The project as in title is a 1991 Audi 90 (7A), The donor engine, harness, and chipped ecu will be from a Audi 200 (3B)
Im just looking for any help as to what i should do in advance of swap, like any engine bay deletes for extra space?
My first plan of action was to clean harness up look for damage or dirty wires, clean them and possibly rewrap with a type of heat protectant, then label each connecter etc..
After that i would dismantle engine, take head to get redone cleaned and polished. Should i leave bottom end intact? Or balance crank and clean cylinders and re ring pistons??
Just looking for any pointers that will help this project run as smooth as butter in the end. Thanks Guys

[Afterthought]

I did one on a 1990 coupe, 86 4000.
For the harness you can get the factory Audi tape from the dealer or you should be able to get similar cloth tape from a hardware store called friction tape.
You will definitely want to find some wiring diagrams, look on here or motor geek.

As far as engine bay deletes, I removed the battery tray, to the back of the car.
I shortened the fuel lines and relocated them, using braided AN hose and fittings. Also deleted the AC but depending on where you're at you might want it.

Once you get the engine set in the car you can start laying out how you want the intake piping, intercooler, all that stuff to go.

For the engine, Depends on your power goals and whether or not you know the condition of the engine (did you see/hear it run or drive? mileage etc?)
If you just want to run the stock ECU the engine is fine to hold that power and then some as is. If you think you are going to go higher boost and big turbo, you'd want to upgrade the rods.
I took mine to a shop and had it honed, replaced rings in the bottom end and upgraded to new forged rods, coated rod and main bearings. I also replaced the valves in the head, stem seals and guides, and had a valve grind done, and had the full rotating assembly balanced. all of that work was under $370 for labor and ~$330 for valves, ~$575 for rods, $180 to have it balanced.

The engine balancing becomes a good idea when you start changing too many things out but if you're doing stock pistons, rods, flywheel, I not think its necessary. For me I changed out the clutch, flywheel, rods so I opted to go ahead and do it for peace of mind.

[Audi_UR]

Sweet, Thanks you very much man. Any clue where to find actual 90 and 200 wiring diagrams? I have the "Bentley Audi 80, 90, Coupe Quattro" Hand book. I can also find the 200 handbook as well. But if i can copy an paste info to my note pad on my mac, it would save me time and hassle

[Afterthought]

You might look at S2Central ( http://s2central.com/main_frame.html ) Paul has compiled a great deal of information there.
Aside from that searching the forum archives on Motorgeek , S2Forum.com would probably yield quite a bit of info.
I have never done the 3B harness but I hear its quite a bit easier than the AAN which I did.

You can also look for an ABY , ADU harness for a more plug a play swap but they are hard to find and usually ~$3 to 400.

I went ahead on eBay and bought a couple of the books from Audi specifically for wiring, (I think they are still bentley brand?) Called electrical troubleshooting manual or something like that.

Look in my build thread there are a couple of pictures of the bottom of the fusebox you will probable need.

[Afterthought]

Actually , here.

Those connections at the top (87a , 0 , m30ac, etc. ) correspond with numbered pins on the bottom of your fusebox. Those would be where your 3B harness would tie in. So for example fuel pump relay provides power to 86, 87a to get your fuel pump working. Pin 0 on the bottom of your fusebox provides power to fuse S26 (which is in your engine harness) for you 02 sensor.
I have never done 3B harness tie in so hopefully someone can let me know if I'm off base. but those are probably your main connections to look for.

Anyways the wiring won't be for a while, gotta get that engine out and engine bay cleaned up first !

When you pull your 7A it may help to leave all the pulleys, belts and stuff on if you have the room. I had my engine sitting complete next to the car so I could use as a reference to see where everything goes.

[maverick]

The wiring is pretty damn close to plug and play. Multiple connectors from the 3b wiring harness plug directly into the bottom of the fuse box in the 90. I would have to check to be sure but I think I had to cut and splice maybe less than ten wires total. Very simple. I've done a few, and just did one on my daily driver a couple months ago. I'd be happy to send you the wiring diagrams for both cars if you're interested, and I'm also happy to help answer any questions you might have about the swap.

[quattrobros]

In my experience wiring a 3B to a small chassis is very simple, but not easy though. Learn how to read the wiring diagrams (i believe there is a guide inside the Bentley). The fuse boxes are the same on both cars so it doesn't get too complicated.

Just remember there are no shortcuts. If you want to do it yourself you have to know what every wire does and where it goes. It seems intimidating at first but once you figure it out its a breeze.

If you have any specific questions feel free to pm me id love to help with the wiring.