What Is A PDM And How Is Haltech’s PD16 So Different?

If you’ve ever wired a race car from bumper to bumper, you know just how intricate of a process it really is. When you’re dealing with a race car that’s using an ECU there’s even more wiring required to make everything work, but that’s where a Power Distribution Module (PDM) can make things easier. In this article, Skylar Drake from Haltech breaks down what PDM is, and how the PD16 from Haltech expands what a PDM can do.

What Is A PDM And What Does It Do In A Race Car?

The concept of a PDM in a race car actually came from the OEM world originally. Most new cars use PDM modules to power the electrical systems that are a part of the vehicle. The high-performance aftermarket saw the value a PDM could add to a race car’s electrical system and adopted the technology. Companies have found ways to use PDMs to give racers more ways to control exactly what’s going on inside a race car.

PDMs are great if you want to cut down on the amount of wiring inside your race car. They bring everything into one central location.

“Much like an ECU is a computer that handles your engine and transmission, the PDM handles other functions such as lighting, pumps, and various powered accessories. In the simplest terms, think of it as a body control module for your race car. Unlike traditional aftermarket boards, there are no fusible links or relays. Instead, the PDM uses solid-state connections to turn on and power devices. This eliminates electro-mechanical failures. They are completely programmable, meaning you can change your triggers/switches all on the fly without any physical wiring,” Drake explains.

You can simplify a lot of the wiring inside the vehicle by using a PDM. – Skyler Drake, Haltech

Now that you know what a PDM is, it’s time to explore what role it can play in your race car.

A PDM is going to assist with eliminating potential failure points in a vehicle’s electrical system. The PDM replaces the need to use physical switches and buttons to activate relays in the vehicle. A PDM also cuts out the possibility of a fuse block being affected by vibrations, or other outside issues since it has been removed from the system.

The PDM is going to make your race car safer since it can identify shorted wires and other electrical problems. A PDM has the ability to test for short in a circuit, and disable that circuit after a set amount of failures have been recorded. You can also program a PDM to shut the fuel system off, cut the ignition, and activate the vehicle’s fire system if an on-track incident occurs.

One of the biggest advantages of a PDM is how it makes wiring easier.

“You can simplify a lot of the wiring inside the vehicle by using a PDM. We have all seen the universal wiring boards that take up a square foot of space in the passenger’s floorboard — with a PDM you don’t need that anymore. You also won’t have to worry about someone accidentally hitting your bank of relays or spilling fluids on your fuse block. You can move a small PDM underneath or inside the dash to clean up your interior,” Drake says.

The PDM eliminates the need for most relays and can be wired directly to your ECU.

A PDM isn’t a plug-and-play item, it does require some wiring and programming to get it integrated into a vehicle. With that said, there’s no reason to fear a PDM, as it’s much easier than many other wiring jobs a racer will tackle as a DIY project.

“In the example of a cooling fan, we would run a power wire from the PDM itself to the fan. The other connection from the fan would be to your chassis ground. That’s it, no relays, no fuses or switches, as the PDM uses information from the ECU to trigger it. The more familiar you become with how the PDM works, the more advanced your triggers and power delivery can be. That’s the beauty of these systems, is they’re infinitely customizable. You can make them as simple or as complicated as you want to be, all the while running a much smaller amount of wiring than you normally would,” Drake states.

Adding a PDM is a great way to inject new life into a street/strip car that’s still using a factory wiring harness. If your vehicle is 15 years old or older, that OEM wiring harness has already started to become brittle and is probably showing its age. The PDM and aftermarket ECU combo can eliminate many of the factory switches and connections that could be on the verge of failure, and it will save you some weight, as well.

“Aside from the benefits mentioned earlier, most aftermarket PDMs have some functionality with ECUs and other controllers. This means you won’t need multiple sensors or switches to turn on various things. You can use one sensor to feed your ECU data, and depending on the communication between it and your PDM, can turn on a variety of devices like fuel pumps, fans and more,” Drake says.

Taking The PDM To A New Level With Haltech’s PD16

Haltech has been creating engine management solutions for over 35 years, and has transitioned into a full vehicle management company. The Nexus R5 Vehicle Control Unit (VCU) added integrated power distribution to an ECU and garnered plenty of positive feedback from customers. Haltech took what it learned from the Nexus R5 and used it to create the PD16, a robust PDM that’s backwards compatible so it could be used with the Elite line of ECUs.

“One of our goals is to simplify things for customers with the PD16. Current PDMs have either a great selection of inputs and outputs, or they have a nice user interface. We feel our product does both really well. Our guys have invested a ton of time and hard work into making all of our products work with the Nexus Software Programmer. Choosing Haltech means you get the best tech support in the industry, and you won’t need 15 programs open and an electrical engineering degree to figure out how to turn on a fuel pump,” Drake states.

Haltech's PD16 gives users a high degree of control over how the PDM functions and interacts with the ECU.

The PD16 is a small device that communicates with an Elite or Nexus VCU through a plug-and-play Controller Area Network (CAN) bus connection. The two half-bridge outputs Haltech built into the PD16 can control just about any push-pull device, like exhaust cutouts, wastegates, dumps, or other devices. There are 10 different high-current 8-amp outputs that can be used for lights, small pumps, or fans. If you need 25-amps for larger devices like fuel pumps, cooling fans, or water pumps, the PD16 has four outputs you can use.

“A lot of new customers think that power distribution module just means a fancy fuse box, but it’s so much more than that. Now you can have safeties built in to turn on/off fans and pumps based on engine sensor data. If you have a short in your wiring, the PD16 can communicate with the ECU to turn off that circuit and even display a warning message on the iC-7 dash display. If you want to truly modernize your racing program, this device will do just that,” Drake explains.

One of our goals is to simplify things for customers with the PD16. – Sklyer Drake, Haltech

As you can see, the PD16 is a very robust and versatile unit that can make any racer’s life easier. The ability to drive different pumps, dumps, fans, injectors, and solenoids is something any race car can use. A street/strip car can benefit from the simplification of wiring by removing fuses or relays that can cause problems and be a pain to troubleshoot.

You can program the PD16 through the same software that you use with a Haltech ECU.

Racers are always more than willing to use new technology if it makes their lives easier. A PDM is a device that can simplify how you wire a car while also eliminating failure points, thus cutting down on those pesky electrical gremlins nobody wants to deal with. Haltech has taken the PDM a step further with its PD16 by creating a device that is small, easy to use, and extremely functional all in one package.

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About the author

Brian Wagner

Spending his childhood at different race tracks around Ohio with his family’s 1967 Nova, Brian developed a true love for drag racing. Brian enjoys anything loud, fast, and fun.
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