With some project cars, we begin with a complete, running car. Over time we upgrade components, or sections accordingly. Some upgrades make the car go faster, others make it stop quicker, or run smoother. An upgrade that many people don’t think about when it comes to performance is the wiring.
The chassis and body were delivered, and the build process was a long one. Wiring the car was done with the help of Ron Francis Wiring, with a ready-made kit to install in the car.
When you build a car from the ground up, such is the case with our Factory Five Racing Project FFR Cobra Jet Challenge, you get to start with a blank slate. We weren’t concerned with old wiring or old connections. We did have to make sure that we followed along with the instructions from Ron Francis Wiring, but we had a slight advantage with the wiring job because most of the hard work was already done for us.
The one advantage to installing our wiring was that Ron Francis works directly with Factory Five Racing to provide a complete kit specifically for the Mk4 Challenge kit car. This takes a lot of the guesswork out of wiring a project car, because the mounting location for the fusebox and many of the circuits are predetermined by Factory Five and Ron Francis.
Rather than the typical labeled bags, the three main harnesses are already loomed and terminated. This makes wiring job, which can be tedious, a simpler process.
Factory Five Partners With Ron Francis
As with many kit cars, like those sold by Factory Five, wiring the vehicle is a part of the build process. Starting from scratch would disturb the build process; the time it takes to determine mounting locations, routing harnesses, and making connections can consume quite a bit of time for the builder and extend the project several weeks, if not months.
Ron Francis makes wiring the Factory Five Mk4 cars a whole lot easier.
The object of a kit car is simplicity; to provide a vehicle kit that is much like the model kits we built when we were younger. For those model kits, everything was already figured out and all the measurements were taken, so all we had to do was paint the parts, and assemble the kit. There was no guesswork as to what parts would fit because that was the whole point of a model kit.
Likewise, the Factory Five cars are designed to be built without having to modify parts or suspension components. The same holds true for the wiring. Factory Five determined what they needed for the harness, where to route it, and how it mounts to its kit cars. Ron Francis was called upon to build that harness kit to Factory Five specs, and Ron Francis provides the entire kit, with most of the harness wrapped and terminated.
The harness is not only precut, but it is wrapped up and completed. -Scott Bowers, Ron Francis Wiring
Ron Francis Wiring’s Scott Bowers told us, “Over the years, the harness has had some refinements and upgrades, but for the most part they are controlled by Factory Five.” Working together, both companies are able to determine the best fit and finish for the harness.
“The harness is not only precut, but it is wrapped up and completed. Think of an assembly line car getting a harness dropped in and connected; there’s only a couple wires in the harness that are not completed and they do come with a flying lead,” Bowers said.
Ron Francis builds the harnesses for the Mk4 Kit cars based on an 11-fuse GM fusebox sourced by Ron Francis, which gets silk screened before the wiring kit is assembled. It then mounts to a Factory Five-sourced plate and is mounted in a specific location as described in the build book. If the builder chooses to mount the fusebox someplace other than the specified mounting location (under the dash, above the clutch pedal) then the harness would not be an accurate fit.
With many of the wires pre-terminated, wrapped up, and connected to the fusebox, the installation time goes by a little bit quicker.
A builder can opt for a universal kit from Ron Francis, but this Factory Five kit is specific to this Mk4 Roadster and Challenge models. Bowers stated that the 11-circuit system is sufficient for Project Cobra Jet Challenge; the kit is designed for this vehicle with a Ford engine and Ford 2G alternator, and does offer a choice of distributors.
Installation Of The Wiring Kit
As we mentioned earlier, with a new build it’s a fresh start, but that doesn’t mean that it can be installed all at once or in any location. With the mounting for the fusebox set to be under the left-side dash, we had to be careful of where panels will come together and where the body will mount. With the tight confines of the Challenge Car, you can imagine how difficult it would be to wire the car after the chassis is built and the body installed.
Although it's a little easier than a typical rewire job, planning out each harness and making sure that it's routed properly is paramount.
With the body off the car, access to the intricate chassis is granted, where harnesses can be mounted and laid out. With the body in place, most all of the wiring is going to be hidden, but you would literally have to be a contortionist to be able to route all of the wires inside the body shell. Some of the wiring is best done as the car is being assembled, because access is far greater. However, since most of the harness is already pre-terminated and cut to length, there’s not much room for straying from the instructions.
You would think a car like this would be easier to wire, but with all of the additional components, cooling fans, and fuel injection, the harness required some outside help.
As we’ve experienced with Ron Francis kits in the past, there’s a method to the madness of wiring a vehicle, and Ron Francis has made that task easier for most wiring kits. The kits typically come in bags labeled with letters, and to begin the wiring you start with the lowest letter and work your way through the alphabet. For the Factory Five harness, the Ron Francis kit is essentially three main wiring sections: front, center, and rear. It’s best to mount the fuse box and install the center harness, then install the front and rear harnesses.
The front and rear harnesses connect to the main body harness. For our application the front harness is for a Ford engine. However, since we have made so many modifications to the vehicle – specifically the eight-stack Coyote mill, AEM Infinity fuel management system, and Radium fuel delivery system – we called upon our friends at 5523 Motorsports to adapt our harness to work with the many additional performance mods we have made to the car.
Getting By With A Little Help From Our Friends
As you can probably guess by now, this build was over the top to begin with, and that meant a little more wiring expertise was needed. We called on our friends from 5523 Motorsports to help us connect what we already had to what we were adding to the build. We started with the Ron Francis wiring kit, an OEM Coyote harness, and and AEM layover harness for the Infinity 708 control unit.
The Ron Francis harness is based on the popular early Ford engines, but when you’re opting to install an advanced EFI unit with ITBs, you can imagine that a lot of work needs to be performed to marry the old with the new. While the AEM layover harness is designed for engine swaps, the addition of ABS, traction control, and other additional sensors required stripping down three harnesses and re-routing a number of circuits.
5523 Motorsports had quite a task, and that included the following:
- Four channel traction control: One sensor per wheel.
- Flex-fuel capability: This consisted of an ethanol content sensor plumbed into the feed side of the fuel system.
- Three fuel pumps: The Radium fuel cell which had a pump cartridge containing a lift pump feeding an integrated surge tank and then two high volume pumps which feed the engine. All three pumps were wired in tandem.
- We integrated a “security system” into the starter motor power supply: This consisted of a third party supplied key fob receiver which is basically a relay controlled by a key fob.
- The supplied radiator cooling fan wiring was removed in favor of more adequately sized high current wiring that was also integrated into the Infinity to allow fan control by the ECU.
- We terminated a CAN BUS connector at the instrument cluster as well as integrated power and ground supply for the cluster.
- We re-wired the fuse block quite a bit: This consisted mostly of changing fuse layout to suit the new system. We also had to add an additional relay for the transmission and differential cooler pumps.
- We added high-current ECU controlled relays and wiring to accommodate the transmission and differential coolers.
- We had to integrate the ignition coil power transistor packs which are required for the factory Ford ignition coils. These were installed inside the dash assembly.
- We added necessary wiring for the two Bosch 4.2LSU wide band lambda sensors and removed the factory Ford air fuel ratio sensor wiring.
- Starter motor wiring was all integrated.
- All of this was fitted inside the dash box so as to minimize exposed wire loom and also to make installation less cumbersome.
You wouldn't think there would be this much wiring for a car like this, but with so many added systems to the car, the harness was quite complicated.
The wiring was completed using Deutsch DT, DTM, and DTP connectors used wherever possible for a clean, professional install that took this car to the next level.
That’s a lot of wiring for a kit car, but there’s a lot of kit car there, too.
The added harnesses and wiring can really complicate things for the average garage mechanic, so calling on the pros to handle our additional wiring projects wasn’t just necessary, it was highly recommended.
The Ron Francis wiring kits can be pretty straight forward when it comes to a basic vehicle, as we’ve experienced in the past. The additional harnesses needed to be fabricated, and unless you have all the proper tools and experience, it’s better left to the pros. This helped us get Project FFR Cobra Jet Challenge that much closer to the racetrack.
The Ron Francis Wiring website will have just about all you need to wire up a project car or to add on to an existing harness. The included instructions with each harness will help make the installation a much easier task, as long as you read them first, and not last.
There’s very little evidence as to how much wiring is under that body, and just how much is going on when the key is turned on.