Race car wiring can be more complex than most anticipate, with water pumps, ignition, lighting, and dataloggers to be powered, then a slew of sensors to monitor everything. Wiring all these components can add weight, intricacy, and add time to the build process. Luckily, companies like Racepak offer their solid-state SmartWire system, which reduces the complexity and weight associated with race car wiring.

Producing 2000-plus horsepower through 8.5-inch tires is no easy task for Evil 8.5, our NMCA West Mustang racecar. It’s a delicate ballet of traction and power that requires the best electronics to get down the track as safely as possible. Therefore, we are pairing our race car with a slew of the compay’s 21st century electronics — a Racepak V300 data logger and SmartWire, to go along with an MSD PowerGrid 7 and Holley Dominator, which will harmoniously share data through a single set of sensors.

Our Vortech-supercharged, Steve Morris-built small-block Chevy bolted into our Fox-body. It was time to get it wired up with a Racepak SmartWire!

Racepak’s SmartWire is like no other wiring system, as it doesn’t use any relays, fuses, or power distribution modules. Utilizing FET (Field-Effect Transistor) technology, the SmartWire sends its power through a solid state board. Dimensions of the unit  come in at a scant 5.5-inches by 6.5-inches by 2-inches thick, and it weighs less than two pounds – a mere 25.8 ounces.

“It was a collaboration between a number of Racepak employees, as there was a need for a power distribution module which would interface with our existing V-Net CANbus system,” explains Racepak’s President Tim Anderson.”

The SmartWire is offered in both a Street and Drag version, though those aren’t the limiting applications for the SmartWire.

“The base SmartWire system includes the main unit, connectors, and terminals, says Racepak’s head SmartWire guru Eric Lowe. “A wiring harness would have to be built from scratch to match your application. Proper crimping techniques would have to be followed and that required crimpers that were a little hefty in price. We sought out to offer a basic harness and decided we could break it into two categories: Street and Drag.

Street and Drag Configurations


Racepak has expanded their offerings for the SmartWire to include both Drag and Street versions. While the SmartWire can be used for any other forms of racing, these two configurations pair up pre-programmed channels and color coded wires to ease installers.

“Each is supplied with a basic harness for a typical install and is pre-programmed to this harness. Connect the wires as labeled and you’re ready to go. There are even a few “auxiliary” wires for input/outputs in case your specific application has a few “uncommon” items that need controlling. On top of that, the units do have open inputs/outputs to add other items should you require this at a later date.”

Why Switch to a SmartWire?

“The SmartWire provides many features beyond an improved wiring solution,” says Anderson.

“As a matter of fact, we try to avoid presenting it as an improved wiring method. The reality is there are still X number of wires in most wiring systems. There are multiple advantages to using a SmartWire.”

    • Programmability: The only option you have for a standard wiring system is the size of the fuse or breaker. That’s it. With a SmartWire, you can program each output specific to not only the current needs but what turns it off and on, using AND/OR fuctions. This also means you can use any number of inputs to trigger an output, vesus a standard switch/fuse panel design.
    • System Status: When used as a standalone unit, the user can connect a laptop to the SmartWire and monitor the status of all inputs and outputs in real-time. This provides an advanced method of verifying circuit operations, when compared to a voltmeter.
    • Sensor Integration: The SmartWire interfaces with all of Racepak’s V-Net sensors, providing the ability to trigger outputs based on values of sensor inputs.
    • Automation: Unlike standard fuse systems, the SmartWire outputs can be programmed to automate the output to vehicle devices. For example: if engine RPM exceeds 3,000, water temperature is under 180 degrees, and speed is above 25 mph, turn off the radiator fans. When speed drops to zero and water temperature is over 200, turn on the fans.
    • Modernization: The SmartWire enables the user to modernize the electronics of any vehicle, especially when using the street SW. Wipers, lights, windows, etc. can all be controlled through the SW. For example, if brake pedal is depressed, ignition is pressed, the power door locks will activate.

Power Handling Capability

The SmartWire has the ability to control 30 outputs: eight at 20 amps and 22 at 10 amps for 8- to 20-volt systems. This means that the SmartWire can switch up to 125 amps of current. Need more than 20 amps or ran out of 10 amp slots? No problem — simply tie two of the 20 or 10 amp circuits together and with a simple adjustment in the Datalink-II software, two separate outputs can be married to one output.

A single power lug on the front of the SmartWire supplies direct battery power for all the switched accessories. If a ground output switch is required for an accessory, a simple relay will need to be used as the SmartWire only outputs a power source.

Our intercooler pump uses the combination of a 20 amp and 10 amp circuit to provide the juice it needs.

Response time on any of the inputs and outputs is set at 3.0 milliseconds max, which means things happen nearly instantaneously after the sensor in question sees the particular trigger point.

Smart Logic for Fuses and Switching

The SmartWire can be used to pair up output channels in the software. Though, if a circuit becomes overloaded, there’s no worrying about burning up the SmartWire. Built-in logic allows the SmartWire to try to reconnect a circuit up to a selectable amount of times before timing out. This will drastically help reduce vehicle fires or burnt up harnesses due to pinched wires.

“With a laptop connected to the SmartWire, one can go into any of the outputs to check their status (normal, in delay, blown fuse, etc), current, and voltage,” says Lowe. “With the onboard LED, it will indicate if a blown fuse exists on the system or if everything is operating normally.

“When diagnosing a circuit, we typically will first want to check any inputs that are controlling a particular output. Simply checking the status on these will allow you to verify that the input is working properly for the current condition in the vehicle. Once that is done, you can go to an output and verify the logic is correct. If it is, your next step would be to check the output status is on and the current. If an output is on but there is now current, something is wrong with either the connection to the device (ie disconnected) or the device itself.”

Each output has a “real-time display” function that aids in diagnosing any issues with an output. The SmartWire will alert once an output is being supplied power.

Racepak’s V-Net sensors can be read by the SmartWire and that data is able to activate inputs. The stackable V-Net sensors are powered by a similar type of technology that’s found in late model vehicles called CANbus (Controller Area Network Bus). The sensor is powered through a CANbus network and carries a unique signature for a given sensor through the same line as all the other sensors.

The switching made through the CANbus system for the SmartWire is made by simple logic selections (equal to, not equal to, greater than, greater than or equal to, less than, less than or not equal to). For example, if your coolant temperature is greater than 165 degrees, the SmartWire can trigger the electric fan to activate. If oil pressure becomes less than 10 psi, a failsafe can trigger the ignition box to turn off.

The V-Net sensors simply plug in front to back and are self powered. One end of the chain will run to the front of the SmartWire to input its data. Additionally, our IQ3 dash, Holley EFI, and MSD Powergrid can pick up all the sensor data to eliminate the need for duplicate sensors.

We asked Lowe what were some unique examples he has seen that showcased SmartWire’s switching capabilities. “Considering you are only limited by your imagination in regards to your particular vehicle sensory system, you could perform a number of actions on a drag car before, during, and after a pass.” A few creative ones would be:

  • Controlling shock dumps/air pressure during the launch, the pass, and in the trap area
  • Activating retards in certain areas of the track to reduce the effects of bumps in the track surface — this will be perfect for our PowerGrid
  • Single button start/run, using the brake switch, time, fuel pump, oil pressure, engine RPM to start a car
  • Multi-stage nitrous system “banking” control
  • Single connector for the delay box to transition between the delay box control of transbrake
  • Controlling the parachute activation based off lateral G-Meter — in case vehicle gets out of shape on a pass, the parachute can be automatically deployed

Additionally, 12 input channels can be used to activate systems. Items like nitrous activation, line lock, clutch switch, transbrake buttons, and more are all events that can be monitored by the SmartWire.

“Ground triggered is easier to set up in almost any case. There is a ground surface that can be tied to near the switch, and therefore it negates the requirement of running a separate power wire source to the switch/button,” Lowe explains. “Although this is easier, one has to keep in mind that the SmartWire doesn’t know if there is a switch/button in place, should the input wire short somewhere between the switch/button and the SmartWire itself. Depending on how critical the input is in channel logics, this could be a big problem. For critical items, power triggered is preferred.”

On the left you can see our current inputs we are receiving into the SmartWire include the brake light switch, arming wire for the Davis Profiler, and remote start button. The outputs can also be triggered via Racepak's overhead switch panel. This self contained unit has a single output wire that attaches directly to the SmartWire.

Dashes and Loggers

The SmartWire has the ability to operate as a standalone electronic device, but its true power is unleashed when pairing it with a Racepak dash or datalogger. With a simple V-Net cable, power, and ground, adding in a Racepak IQ3 or UDX dash couldn’t be easier. The SmartWire does monitor what the vehicle’s sensors are doing, but it doesn’t have the ability to record or display that data, which is why we are pairing up our Evil 8.5 Mustang with a Racepak V300SD data logger.

Integrating Racepak's dashes and data loggers is simple; a V-Net cable, power, and ground are the only basics you need. Our IQ3 is held in place by a Team Z Motorsports race car mount.

Interfacing with the MSD PowerGrid and Holley Dominator

So how easy is it to integrate the SmartWire with other systems? Easy as pie. MSD’s PowerGrid was already built to accept a V-Net input wire (using a T-cable) and works with most of Racepak’s data loggers. Once connected to the software side of the V300SD logger, a simple read/write of the configuration file will update the data logger’s configuration. The channels being outputted to the data logger can be changed in the PowerGrid’s software.

Almost as easy as the PowerGrid, the Holley Dominator is able to read all our V-Net channels by adding a Racepak interface module. This module will convert the Holley Dominator CANbus signal to a V-Net CANbus signal, and vice versa, so sensors can be read by either device.

The completed SmartWire harness by Jordan Innovations. Each connector is clearly marked on its location.

Smart Wiring Tips

When it comes to building out a harness, we turned to Jeff Jordan of Jordan Innovations. A seasoned electrical engineer, Jordan is equipped with all the correct tools needed correctly wire a race car. That doesn’t include wire crimpers from your local auto parts store!

Use of proper crimpers is a must. – Eric Lowe

For those do-it-yourselfers, Lowe provided some suggestions. “Use of proper crimpers is a must. Some people will try to get by with a typical Weather Pack-style crimper. This unfortunately creates a “W” style crimp on the terminal where it goes around the wire insulation. Crimp wise, it would be sufficient, but the housing that the terminal is inserted into is tight and designed for a round-style crimp. The “W” will be too wide and will not allow the terminal to be inserted all the way into the housing. This would then not allow the terminal to make contact with the pin on the main unit.”

Lighter, Faster, Smarter

Racepak’s SmartWire is a revolutionary wiring system for any vehicle: it harnesses the power needed for a racecar and seamlessly provides voltage without worry. Being able to integrate sensor data from Racepak’s V-Net data stream eliminates the need for duplicate sensors. Furthermore, conditional formatting allows the SmartWire to trigger outputs automatically, which is especially critical when used as a failsafe. Now weighing less with a simplified vehicle harness, we’re looking forward to getting Evil 8.5 down the track.