Engine Bay Electrical
Here is the chance to either make a mess or make it look nice. I still remember cleaning up all the wild-goose chasing wiring from my old engine way back when. That was a much simpler task with a good Carb-fed engine. Fast forward a couple of years, and here we are with an engine that has more sensors and wire than my whole car used to. Either way, if you take a bit of time with some good forethought it can still come out nice and neat. That and I still wanted to keep a good line of sight to those sweet looking headers.
Finding the ECM a home
Once I had the main engine harness back on, this kinda fell right into place. On the new mustangs the ECM is tucked in nice and tight next to the exhaust manifolds facing the other direction. I felt it was better to go the other direction and tuck the ECM where the battery used to go. That still leaves me plenty of room for the power distribution box and wiring. So I cut up some angle iron and fashion two brackets to securely mount this piece down. Luckily there is barely enough room to slide the connectors in and out without having to take the ECM off. Some people may want to hide this in the glove-compartment, but I like to show off the motor and everything that goes with it. Plus it's just alot easy to troubleshoot and work on if you need too.
Tiny Holes are better
With the Ford Racing Controls Pack for this motor, they include this really slimmed down AUX wiring harness. This includes things such as gas pedal, intercooler pump, electric fan, power, OBD-II port, etc. The thing that struck me weird was that they wanted me to drill something like an 1.5" hole in my firewall to get the gas pedal plug and OBD-II port through. Yah, well I didin't want to do that, so I decided to take the plug housings off and just feed the wires through the smallest hole possible. Here are a few pictures of the original harness, the hole I actually drilled, and the back of each plug for wire color reference. Ford did a great job with their documentation, so it was very easy to check with a DMM to make sure everything was wired correctly after the harness was fed through the hole. BTW, you might notice alot of other cables being fed through the same hole as this harness. Yup, those are all other body wiring for the front of the car. LOL, you'll be surprised what you can pack into a 1/2" hole.
Power Distribution Box
Next thing to find a home was the compact Power Distribution box that came with the Ford Racing Controls Pack. What really nice is that this connects directly to the engine harness power connector (big green plug), and has all the fuses and relays to run the motor. Ford also did a nice job with some status lights that you can see from the top of the box. Anyways, the engine harness really defined where this was going to locate. Turns out it was a perfect spot on the inner fender panel. Here all the wiring and A/C hose can run under the box and not be an eye-sore in the engine bay. So far in this picture I just layed out the main engine cables. The body wires are still tossed over the fender in the back of the picture.
Laying out the wires
Here is where it helps to really bundle the cables together and see how they flow. I first used plenty of zip-ties and electrical tape to hold everything in place as I was making adjustments here and there. I tried to keep my body wires and the AUX harness all together to basically make a single wire bundle (more on that in a bit). Now there were a few extra +12V battery hookups to make at this point, but I tucked them in nicely under the main engine power cables. This keep wires from criss-crossed to a bare minimum. And if your curious, I crimp, solder, heat shrink, then cable wrap all my connections (yah it's a bit over kill but it works like a charm). Also, for the Ford engine harness there were those nifty built in cable mounts that I took advatange of by drilling a simple hole in the inner fender panel to keep everything tight. If you notice in the final picture there is a heavy 4-pin weatherpack connector for some special.
Fans of Plenty
So the trick with any supercharged motor is keeping the incoming air as cool as possible. The OEM water to air intercooler does an alright job to keep that air cool. But I've heard of alot of problems with heat-soak in the GT500s. Basically heat-soak is when the incoming air gets too hot so the ECM cuts the power level to keep from blowing the motor apart (pre-detonation). Anyways, a good aftermarket upgrade is to get rid of the standard single-pass heat exchanger, for a dual-pass one. The next step is to add high-speed fans to the heat exchanger to make matters even better. So I decided to go with the all-out setup, hence the fans and dual-pass heat exchanger. I thought the original Spal fan connecters were cheap, so I replaced them with a nice weather-pack connector to compliment everything else.
Fan Power
When I purchased the C&R heat exchanger they sent me two fan relays and two fuse holders. I looked up the specifications on the fans and they only pull 7.5 amps each. So I decided to run a single +12V battery wire to a single relay. This relay then feeds two fuse holders which in turn feed the fans. This way I have fuse protection for each fan, yet only have to mount a single relay. FYI, the relay is good for 40 amps, but I'm only using 2x 15-amp fuses (30-amps total). Oh, and this relay turns on with the intercooler pump to keep the car quiet when it's not running.
Covering the Bundles
I think this step is the one that is forgotten just a bit too much on cars. This is where you go back and cover all the loose wires with a nice braid of some sort. I picked up several different sizes for split braid from the store to really finish out the wiring in the engine bay and get it looking "finished." That and adding a few wire clamps here and there really pull everything together nicely.
