Tech: Racepak’s Solid State SmartWire Power Distribution Module
Ever since the very first automobile incorporated electrical components, there has been a need to power those components through some sort of switch in order to control the on and off state of said component. In the beginning days of automobile development, this technology relied on glass fuses, which although functional, didn’t really offer the durability that was necessary in a high-stress environment. Later on, the industry moved into the use of electronic relays and solenoids to perform the same functions – turning electronic devices on and off inside the vehicle.
Racepak has taken the electrical system’s design many steps further with its integrated SmartWire technology for racecar applications, and in this article, we’ll detail what makes it so special and why it’s one of the products revolutionizing the use of electronic devices in the racing industry. We installed one into our Project Biting The Bullitt ’65 Mustang, which makes an outstanding 1,000-plus horsepower through the use of a 427 cubic-inch small-block Ford engine with a blow-through Paxton Novi 2500 supercharger providing 16 pounds of boost to achieve those insane power levels.
Driving The Bus
The SmartWire concept came from today’s OEM technology, which relies on CAN Bus (Controller Area Network Bus) protocols along with other control methods to achieve the same end result as the use of those glass fuses, albeit with a much greater level of precision and specialization. Getting down to the nitty-gritty, CAN Bus is an internal communications network that connects components inside the vehicle and offers a high level of EMF noise resistance, relative low cost, and assurance of message delivery.
We spoke with Racepak’s Eric Lowe, who explained some of the finer points of the SmartWire, “Simply put, the SmartWire is a fully programmable solid state device for distributing power around the vehicle. Replacing traditional fuses, relays, circuit breakers, flashers, etc, the SmartWire wires in with switches/buttons on the inputs and your devices such as lights, fuel pumps, ignition, fans, pumps etc. on the outputs. This significantly reduces the complexity of the wiring in the vehicle as well as providing a more reliable controlled electrical system. A nearly unlimited variety of “and”/”or” on-off switching logic/functions are user programmable in the configuration file through the DatalinkII software installed on your laptop.”
SmartWire’s FET Technology
FET (field-effect transistor) technology allows the SmartWire to control current and voltage without a single relay, fuse, or switch – it’s all activated and deactivated through the solid-state board inside the SmartWire. Although the installation in Biting The Bullitt is on the simple side, the capabilities of this box are nothing short of amazing. Racepak’s Eric Lowe explains, “When utilizing a SmartWire, it is possible to instantly re-purpose an input/switch/button to control other devices, it is just a simple configuration change with no wiring change required. Should you want to activate an output when two buttons are pressed together, again, it can be done with just a config change – simple and elegant.”
How does the SmartWire work? It’s quite simple in theory. The SmartWire is installed between the car’s battery and the devices that need to be turned off and on, using FET technology.
SmartWire's FET Technology
FET technology allows the SmartWire to control current and voltage without a single relay, fuse, or switch – it’s all activated and deactivated through the solid-state board inside the SmartWire. Although the installation in Biting The Bullitt is on the simple side, the capabilities of this box are nothing short of amazing. Lowe continued, “When utilizing a SmartWire, it is possible to instantly re-purpose an input/switch/button to control other devices, it is just a simple configuration change with no wiring change required. Should you want to activate an output when two buttons are pressed together, again, it can be done with just a config change – simple and elegant.”
The SmartWire receives input from the various programmed sensors (temperature, pressure, speed, etc.) used in its operation, and in turn sends signals out to other components like the fan or transmission, to help control operation of the vehicle as a whole, and it is this type of technology that is self-contained within every SmartWire system – making it perfect for racecar applications where things happen much more quickly than in a passenger car, and helping to simplify things for the driver and crew. Racepak states that when individual items can be controlled by the SmartWire’s solid state technology, it helps the vehicle to perform more consistently and with more accuracy, takes some of the mundane tasks out of the driver’s hands – simplifying the electronic controls within the vehicle.
What Does It Connect To, And How?
Even more attractive is the fact that SmartWire can be used in three distinct modes for all types of users. In stand-alone fashion it can control all of the electronics in a hot rod; the second mode allows it to be tied in to monitor/activate/deactivate the vehicle’s functions using Racepak’s V-Net sensors, while the third mode is where it begins to shine – when a Racepak V-Net datalogger like the super-popular V300 or V500 is added to the equation.
So let’s talk about those three modes of operation, because once you understand how the SmartWire really revolutionizes the wiring aspect of a vehicle you might see how it could benefit your program like it did ours.
In standalone mode, you connect the battery to the power stud on the SmartWire, and each output needed for the vehicle is wired in to one of the two 23-pin connectors on the side of the unit. From there, the end-user uses the USB link to the DatalinkII software to set up the output current and related requirements for each individual item. The user can choose to set up the SmartWire to handle switching each individual component on and off through the box itself, or through a manual switch on the optional SwitchPanel or SwitchModule offered by Racepak.
When you use it in conjunction with the Racepak V-Net sensors is when things really start to get interesting, because you gain hands-free, nearly infinite control over how each electronic component in your machine operates. For example, if you have an electric fan that you want to turn on when the coolant temperature reaches 190 degrees – it can do that. Just add one of Racepak’s V-Net water temperature sensors, connect it to the V-Net port on the SmartWire, and program it through your PC. Want the engine to shut off if oil pressure gets to low? Simple.
“You can trigger everything through the conditions in the internal switching. For example, we have an MSD 7531 in the car, and I can trigger the timing retard conditions if things start to go wrong,” explains car owner Mark Gearhart. “This can include a lean condition via the air/fuel ratio monitoring, intake air temperatures that get too hot, or even if the fuel pressure drops off.”
Datalogging Simplicity Included
For you racers that already have a Racepak V-Net datalogger or are planning on adding one, the SmartWire gets installed inline with the V-Net T cable, which transmits all of the sensor data to the datalogger. Since the data is already passing through the V-Net cabling to the logger, the Smartwire ‘sees’ all of the information and can be set to trigger each device based on the settings that you program into it. Programming of individual inputs and outputs in this instance is achieved via the V-Net cabling through the datalogger itself, rather than through the SmartWire port.
You can have a wideband air/fuel ratio monitor hooked up to it, and if the wideband detects a crazy-lean condition, I can have the SmartWire trigger the MSD 7531 to retard the timing. – Mark Gearhart
With the datalogger installed, you can monitor everything that the SmartWire is operating and recording in the DatalinkII software. What this means to you, Mr. End-User, is that you can clean up the nasty wiring mess that the guy before you created (wink-wink), simplify everything on and in your machine – and add completely-programmable capabilities to all of the devices installed at the same time. Since it’s society’s “thing” to record everything these days, you can add that datalogger and have graphs to interpret forever. It’s the science behind the simplicity that makes the SmartWire so attractive.
In addition, it will also interface neatly with one of Racepak’s G2X Pro, UDX Replay, IQ3 logger or display-only digital dashes, giving your machine the ultimate in cutting-edge technology both under the hood and inside the passenger compartment.
One of the places where the SmartWire really shines is in the diagnostics department. As Lowe explained, “If you suspect a connection is loose or may be causing the issue, normally this situation would lead to visual inspections of wiring looms and a lot of other time consuming inspections with a multimeter but with a SmartWire/data logger combo, things become a lot easier. The state and current draw of each output on the SmartWire is sent out on to the V-Net, where a data logger can read and log these parameters. This means that in the above scenario you can simply look at the data, find an instance where the RPM has dropped coinciding with the miss that is being noticed and then see which output current dropped at the same time allowing you to instantly understand in which circuit the problem might be.”
What’s in the box?
The SmartWire box itself is not very large or heavy, measuring only 5.5 inches x 6.5 inches x 2 inches, and it weighs just 25.8 ounces for you weight-conscious racers. There are 12 hardwired direct inputs that are either voltage triggered (over 2.7V) or ground triggered (under 2.5V). There are 30 outputs, 8 of which carry a 20 amp load and 22 of which carry a 10 amp load. If you need 40 amps for a circuit, simply wire two of the 20 amp circuits to the needed source.
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. Max output capacity is 125 amps, which is plenty to handle anything you can throw at it – this thing was designed by the racers at Racepak, who know that you’re going to be driving multiple nitrous systems and/or engine management systems with 16 huge fuel injectors on top.
A single quarter-inch power stud right on the top of the unit receives power from the battery, while there are dual 23-pin Ampseal connections on the side of the unit that comprise the hardwired direct inputs, outputs, ground, and shutdown pin. Each output is monitored for current, voltage, and status. They are protected by user-settable limits for over-current situations to prevent any damage to the components themselves.
Two status LED’s are at the bottom of the unit, one for power and one for status. The power LED will glow red as long as power is connected correctly, while the status LED will be green as long as each component is operating correctly. It will glow red when a fuse event has been triggered.
The output wires are connected for each individual component directly to that component, and the inputs are used for event monitoring like a transbrake, or external manual switch connections. It’s recommended to use the Racepak SwitchPanel or SwitchModule (which simplify things by attaching to the SmartWire with just one small cable), but there may be an instance where you need to add another external switch, and that’s where these inputs might be necessary.
We discussed wiring and its requirements with Racepak’s Lowe, and he noted a few salient points to pay attention to when configuring your electrical system. He explained, “Once you know how much current your device will draw you can then determine what gauge wire is appropriate for your device, based on the previous measurement along with the distance between this device, ground location for device, and the SmartWire. The wire selection should be sized accordingly to handle the load of the entire circuit.”
He continued, “When connecting devices to the SmartWire, you must make sure you use a wire that is rated for the current (amperage) that the device is going to pull. It is always better to have wire that is over-rated rather than a wire that is under-rated. If wire is used that is not rated to handle the current that your device will pull, the result could be overheated wires that could possibly melt the insulation of the wire causing a short or result in a fire. Normally this will be prevented by the settings in the SmartWire if they are programmed appropriately by the end user beforehand.”
Special care should always be taken when sizing wires to the work load. – Eric Lowe, Racepak
Programming the SmartWire
Since there is a 44-page booklet on how to program the SmartWire, obviously we won’t be able to get into all of the operations here in this article. What we can tell you, though, is that once you follow the DatalinkII software installation instructions within the booklet, and power the SmartWire unit up with a power and ground connection, you can then begin to label each connection so that the unit knows what parameters it needs in order to operate.
It is suggested to have a general plan for the inputs and outputs before you ever run a wire, so that you can keep everything neat and clean upon installation. After all, the main reason you’re putting these parts into your car is to clean up the mess you had before, right? Keep in mind that certain items like ignition boxes will still need their main power source to come directly from the battery – the SmartWire is just a switching control unit, not a main power source.
Each output is also protected from short-circuits and/or thermal overload situations. Each output has a variety of different states: Constant On, Flash, Latch On, Single Pulse, Windshield Wiper (channel 19 only), and time-delayed for on-off operation. The outputs are controlled by any combination of the following: switchable inputs, V-Net attached sensors (temperatures, pressures, RPM, etc.), and a variety of programmed logic operations (equal to, not equal to, greater than, greater than or equal to, less than, less than or not equal to).
What items will you be connecting and using as the inputs? (switches/buttons)
- Starter Button
- Ignition Switch
- Light Switch
- Fuel Pump
- Electric Fan
- Water Pump
What will each of the outputs connect to?
- Starter solenoid
- Ignition system
- Fuel Pump
- Electric Fan
- Water Pump
What conditions/logic will be used to control the outputs?
- Starter button for solenoid activation
- Ignition Switch to turn on Ignition/ECU/Fuel Pump
- Light Switch to turn on lights
- Cooling switch to turn on electric fan(s)/water pump
One of the unique ways we’re using the SmartWire system in our installation is to trigger the Fuelab fuel pump’s high speed operation. Once the system sees above five pounds of boost, we’re able to turn on the pump’s high-speed capability without the use of an external fuel pump speed controller or any relays – truly simplifying the operation of the fuel system.
As you can see, despite the fact that the SmartWire uses the most current technology, in its very basic form, it’s just a control center than turns things on and off. Is it the right choice for you and your car? We can’t answer that question, but hopefully we’ve given you some insight into how it works and the features it has to offer, so that you can make your own educated buying decision. There’s lots of information on the Racepak SmartWire website, too – including installation and programming manuals, so head on over there to check it out.