I'm sizing up a 13b EFI swap on my 79.

I kind of snooped around a bit under the passenger carpet and didn't really see a good spot to mount an ECU as there is nowhere to fit a protector plate or mounts from the factory. How and where do most of you mount an ECU when you swap a 12a out for a 13b EFI?

I'm also curious about the driver side 13b and 12a harness interchangeability. Do most of you completely remove the 12a main driver side harness and install the 13b harness in its place? OR do you keep the 12a harness and just run new wiring for the new 13b equipment?

 

My car is an 82. I didn't use the stock S5 ECU, but my wiring harness was completely rewired for the new ECU. The ECU is behind the center console in the space under the radio and behind the ash tray.

 

Leave the stock harness as is and just run the needed wires to run the 13b, thats what I did anyway. To mount the ecu I built a mounting plate similar to the stock FC's part and mounted it on the passenger "toe board" I made the plate thick enough that if hte passenger puts their feet there it won't hurt anything...
I was going to put it behind the center console like purple82 said, but the gauges i was running didn't leave enough room for it....

 

I was thinking about stashing it in or behind the glove box...

 

There is a good deal of space over the glove box in the 78-83 dashboard. I had a small stereo amp there for a while.

Just test fit it there with all the cables installed first to make sure it fits and you can get the harness plugged and unplugged in case you have to replace something later. The only problem in that space for me was that there isn't a lot of places to bolt something to.

 

I figure since most of the places to bolt onto are plastic I'll have to run a thick ground from the ECU frame to the inside of the chasis anyway. I can use zip ties or something if need be in that case.

 

Really? All my AC and blower components fill that space up I can barely reach in there.

I'm thinking of making extensions on my harness so I can put the ECU behind my seats.

 

Those components are under and behind the glove box, at least on my car. There's nothing in the space above it.

 

Like all electronics, ECUs don't like to be shaken so wherever you put it, make sure it's tied down very securely to something that's rigidly attached to the car.