Take Your UTV To The Next Level With A Racepak SmartWire PDM

10 min read

Take Your UTV To The Next Level With A Racepak SmartWire PDM

10 min read

UTVs are exploding in popularity, not just for recreational use but as full-blown off-road race cars. The light weight, 4WD, and gobs of wheel travel make them the perfect platform to build for desert racing, and UTV classes often have the most entries at many races. While it is important to be fast, that won’t translate to wins if your UTV isn’t reliable. This line of thinking motivated Alex Baker to wire his Can-Am Maverick X3 with a Racepak SmartWire PDM as a key component in his frame-up transformation from stock to race ready.

You have likely heard the word “PDM” but may be fuzzy on what this term actually means. A PDM is a Power Distribution Module, and it replaces a traditional fuse box with solid state electronics. While traditional wiring provides control of vehicle electronic components through the routing of fuse, relay, and circuit breaker panels, the Racepak SmartWire functions as centralized power distribution for all vehicle wiring. “Solid state” is another term that is often thrown around. At its most basic “solid” means no moving parts. This is particularly valuable on a race car subjected to the harsh desert environment and endless shaking and vibrations. In the case of the SmartWire, “solid state” refers to the solid-state relays and transistor switches, which have no moving parts.

Can-Am Maverick Chassis

Alex Baker tore his UTV all the way down to the chassis with the intention of creating a purpose-built race machine. From UTVs to Trophy Trucks, a SmartWire PDM is a “smart” investment if you are wiring an entire vehicle from scratch. Even if you are just adding accessories, a PDM makes more sense than an auxiliary fuse panel and provides infinitely more options, both now and in the future as your needs change.

What Does the SmartWire PDM do?

A PDM can be added to power auxiliary items such as fans, lights, and a race radio, but it is best utilized to replace the entire wiring system in a vehicle. There is even a street version (PN 500-KT-SWST) and a drag version (PN 500-KT-SWDRAG) of the SmartWire PDM that come with prelabeled harnesses to easily wire your entire vehicle. Since street cars typically have items like turn signals and windshield wipers that drag cars do not have, the street kit comes with 16 circuits while the drag kit is all business with eight circuits for items including the fuel pump, starter, etc. For Baker’s Can-Am, he used the standard SmartWire PDM (500-KT-SW30) and wired it himself from scratch to control his dual, redundant fuel pumps, electric fans, and a host of sensors that feed information to the RacePak IQ3 logger dash through the V-Net cable. This is not a particularly fast or easy process, but that comes with the territory when you are building a race car from the ground up. The SmartWire comes with a pinout list that designates whether each pin is available for output (10 or 20 amp) or input (which can be used as a voltage trigger or ground trigger, assigned in the Datalink II programing software).

Lightweight Benefits UTVs

The design of the SmartWire PDM reduces overall installation weight and clutter, while contributing to a quicker reacting electronic system, through the solid-state switching design. The RacePak SmartWire only weighs 1.5 pounds, another advantage when racing in the UTV class, where all the vehicles have very similar horsepower. Less weight to accelerate, decelerate, and control though the desert results in a faster vehicle. In addition to being light, to be successful in the off-road race world a vehicle has to be reliable. The easiest pass someone will make is when a competitor is stopped on the side of the track trying to troubleshoot an issue. We want to be the one making the pass, not getting passed.

Racepak Smartwire PDM mounted

The most important consideration when mounting the SmartWire PDM is selecting the proper location. Choose a mounting location that allows easy access and cable routing. In this case that was directly under the dash where the SmartWire PDM is protected from damage but easy to access with the panels removed. Mount the SmartWire using the four rubber shock isolators “feet” provided. This will protect the unit from shock and vibration damage.

Low Power Consumption for Your UTV

Power consumption is another important factor on UTVs, as they use a stator instead of a traditional alternator and only produce a limited amount of amperage. Baker manufacturers a driveline mounted alternator for Can-Ams through his company Baker Power Products, but the low power requirements of the SmartWire PDM is still a huge benefit when you consider the additional draw of off-road lights, electric fans, a 110-watt race radio, GPS navigation, and more on top of the factory power steering, ignition, and lighting. It isn’t uncommon for UTV racers to have to choose between their air pumper, cooling fans, and lights at night.

This is where the immense flexibility of the SmartWire PDM really outshines a traditional fuse box with relays or even circuit breakers. Each input and output in the SmartWire PDM is fully user-definable including; function, power requirements and current exceeding limits, via a USB connection to user's PC running Racepak’s free Datalink II programming software. With conventional wiring and fuses, as soon as that fuse blows, the circuit is null and void until you stop and replace the fuse. This is the last thing we have time to do in a race situation. With the SmartWire PDM, you can actually set the power distribution module up to retry a circuit when the conditions change. So we can program our power hungry electric fans to only draw amperage when the temperature gets beyond a temperature we program, or the off-road lights turn off when the input voltage is too low to sustain them. Now you know why they call this PDM Smart!

Racepak SmartWire PDM keypad

Designed specifically for use with the Racepak SmartWire PDM, this keypad (PN 500-KT-KPAD8) allows user input for eight functions. In Baker’s case those functions included the Spal fans on the Earl’s oil cooler, additional electric fans on the radiator, the two redundant fuel pumps, the fresh air system, the top light bar, and the front light bar. The keypad was wired to the PDM with a 36-inch cable (PN 580-CA-BN-036), but they are available in various lengths from 6 all the way up to 120 inches.

Just How Many Amps Does Each Item Draw?

There are 30 total output channels, 8 20 amp circuits for higher amperage items such as fuel pumps and 50-inch light bar and 22 10 amp circuits for things like the GPS, fresh air system, and the siren. If your fans (or any other circuit) draws more than 20 amps, two 20 amp circuits can be paired together to double the amperage, but only pair circuits with the same amperage (don’t combine a 20 amp and 10 amp circuit).

Once the PDM is mounted it is time to wire it and program all of the circuits. The DataLink II software displays amperage for each circuit, making it easy to determine how much they draw. In this specific case that included:

  • Starter solenoid- 10 amps
  • Fuel Pump 1- 15.24 amps
  • Fuel Pump 2- 15.08 amps
  • Radiator Fan 1- 15.39 amps
  • Radiator Fan 2- 15.39 amps
  • Oil Cooler Fans- 8.22 amps
  • Headlights- stock wires
  • Front Light Bar- 8.44 amps
  • Top Light Bar- 22.60 amps
  • Roof corner lights – 7.11 amps each
  • Rear Light Bar- 0.79 amps
  • Air Pumper- 4.21 amps
  • Race Radio- direct to battery to limit “electrical noise”
  • Intercom- direct to battery to limit “electrical noise”
  • Siren- 8.08 amps

Programming with DataLink II Software

Should the current exceed the fuse setting for extended periods (more than 5-10 seconds) the output will be deactivated. For each item, a cutoff current was initially selected that was approximately 50% higher than the anticipated draw for a safety buffer. Fans were programmed to turn on at 175 degrees and shut off again once temperatures dropped below 160 degrees. The auxiliary lights, while important, were the first things to shut off when the voltage drops below 12 V. Next is the fresh air pumper, then the oil cooler fan, then the intercom. While the hope is to never lose functionality of these items in a race, the larger priority is reaching the finish line. That goal was accomplished, as Baker and his teammates reached the finish line at the 53rd SCORE International Baja 1000 in a newly built UTV with zero electrical issues. As Louis Pasteur said, “Luck favors the prepared.” In this case, luck favored the Smart(wire).

Racepak Smartwire PDM programming

Just like most things in life, the more time you invest in programming each circuit, the better the results will be. The beauty of the Datalink II software is that it is easy to use, so going back and performing fine tuning is not only possible, but encouraged. Don’t be overwhelmed by the number of options, you don’t need to alter more than one or two parameters when making updates.

Racepak SmartWire PDM labels

The SmartWire keypad comes with a host of labels to allow you to customize the display and easily identify which switch is for the electric fans, fuel pumps, fresh air system, and more. There are 40 premade labels, along with generic labels for auxiliary switches, and blanks to make your own custom labels. Want to sandbag at the track or provide an extra level of security against theft? Be deliberately vague (or misleading) with your labels.

Racepak Smartwire PDM power wire

Power into the SmartWire PDM comes directly from the battery to the 1/4-inch stud. In this case, two Odyssey batteries are mounted to the tubework of the chassis adjacent to the SmartWire. In situations where a main power cut-off switch is required, the SmartWire main power should connect to the switched side of the cut-off switch to ensure power is removed from the battery as per the rules.

Racepak SmartWire PDM ground wires

Note that three separate ground wires are required to ensure proper grounding. Pins A19, A20, and B19 must be securely connected to the battery negative terminal or to a secure chassis ground. Do not connect the three wires together and run a single wire to ground. Three separate, correctly sized wires need to be connected to the battery negative post.

Racepak SmartWire PDM V-Net Port

The Racepak V-Net compatibility of the SmartWire PDM allows seamless integration with existing Racepak V-Net equipped vehicles. In the case of Baker’s Can-Am, that is a RacePak iQ3 dash and data logger that is covered in detail in another article. When connected with existing V-Net equipment, these items provide additional inputs, control modules, and instrumentation, compared to when utilized as a standalone power control module.

Racepak SmartWire PDM Power

There are two lights on the SmartWire PDM that can be used for quick reference and troubleshooting, a Power Light and a Status Light. When the power is on with no issues the Power Light is solid red and the Status Light is solid green. If the Status Light is solid red it indicates the equivalent of a blown fuse. If the Power Light is flashing it indicates a firmware update failure.

Racepak SmartWire PDM wiring

The smaller the wire diameter, the greater the resistance and thus lower current capability over a given length. When in doubt about wiring size, err on the larger side. Factors can affect the load capacity of a wire, besides length, include temperature, duration of load, stranded versus solid core wire, and wire plating. Higher capacity wiring utilizes silver plating with a higher strand count and as such will typically have a higher capacity, when compared to copper stranded wires.


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