Spark Specialty: DUI Distributor Tech With Performance Distributors

Though largely a thing of the past, distributors have been a mainstay of automotive design for many vehicles, including trucks and SUVs. Performance Distributors specializes in not only offering replacements for distributors on classic engines, but improving on the original. This translates to a product that can take an off-road beating, and still come out working perfectly.

Performance Distributors’ flagship product line, D.U.I. (short for Davis Unified Ignition), offers customers a versatile and robust distributor that’s worth exploring. Combined with its premier line of ignition wires known as LiveWires, this becomes a one-two punch that will re-energize the engine and keep it running for the long haul.

The Davis Unified Ignition (or DUI, for short) is Performance Distributor’s premier distributor, improving on GM’s HEI design and offering better spark.

We reached out to founder Steve Davis to hear more about these products and see how they stack up against standard OEM replacements in Ford, GM, and Toyota applications. In doing so, we learned just what makes DUI and LiveWires distinct, and why they should be at the top of your list for a fix-it project.

Product Background

Distributors are all but non-existent in cars and trucks today, but they used to be a mainstay of engine ignition design. Davis has been a lifelong devotee to distributors and their technology, and has a wealth of knowledge to draw from. To get a better understanding of the framework and timeline of distributors, we asked Davis to share details.

“Distributors were the reigning champs of ignition design up until the 1980s,” Davis explained. “Take GM and Ford, for example. For GM, their approach was a little varied, but they stopped using distributors by 1986. Fords went computerized in 1988.”

For folks that run older vehicles like Blazers, Broncos, FJ40s, and other popular applications, a bad distributor is a roadblock to getting back out and experiencing fun on the highway or local trail. Going with a Performance Distributor DUI distributor not only restores the engine to running order, but also ensures it will run better and longer than an OEM distributor. How, you ask? Let’s explore some things that separate the DUI from a run-of-the-mill OEM distributor.

What Makes The DUI Different

By outward appearances, a DUI and an OEM replacement distributor look similar. “In 1975, GM started using the HEI, or High Energy Ignition. The DUI is our type of HEI distributor, using the same inherent design that GM developed. However, we’ve made significant improvements compared to the HEI, and adapted the housings so that they can work on multiple brands like VW, Toyota, and others.”

One key improvement was the interior of the distributor. “Rather than put our coils and electronic modules outside of the housing, the DUI has those components mounted inside the housing,” clarified Davis. “This keeps them safe from outside heat and debris, and also cleans up the wiring.”

Another aspect of the DUI is its enhanced coil and module. “Our DUI will put out a longer-duration spark, which makes for a higher voltage reaching the spark plug,” said Davis.

“This lets you run the spark plugs at a much wider gap than normal,” he continued. “Typically, stock is .035 to .045 inches, but with our DUI’s voltage boost, we can increase that to .050-.055 inches. This, in turn, helps make more power and efficiency in the combustion process.”

LiveWires are the spark plug wires that form a perfect pair with a DUI. Spiral-wound and insulated against heat, they transmit low-resistance voltage directly to the spark plug.

Bolstering the efficacy of the DUI are Performance Distributors’ LiveWire spark plug wires. These plug wires go great with any DUI, as Davis explained: “For all of our distributors, the LiveWires are the perfect complement. They’re spiral-wound to prevent radio interference, and have a low resistance (at least 300 ohms per foot in resistance), which delivers the spark from the coil a lot more effectively.”

Further enhancements to the LiveWires include heat shielding around the wire, which helps insulate the wire from excessive heat, as well as repelling and dirt and moisture. “If you go off-road or live in a dusty environment, this is something you’ll like to have in the engine bay,” commented Davis.

Quality And Durability

A DUI starts with a raw casting that is lathed and polished before assembly.

Any company worth its salt stands by its product and follows a stringent manufacturing process. Performance Distributors adheres to this policy as well.

“We take our QA and manufacturing seriously,” affirmed Davis. “The DUI has to mesh with the camshaft gears exactly, so we make sure our fittings are very precise, otherwise damage could occur. During research and development, a prototype DUI undergoes testing on a guinea pig vehicle for at least 2,000 miles, so we can be sure that it’s working correctly.”

On every DUI distributor, the coil is mounted to the cap and the electronic module rests inside the housing. “This protects from mud, dirt, and water,” commented Davis. “It’s good to have this kind of internal protection.”

During manufacturing, every DUI undergoes a stringent procedure. “We lube both the upper and lower bushings of the housing so that when the shaft is in the housing, you get a nice, true spin,” said Davis. “We also check on the gear using a feeler gauge. That lets us know the tolerance between the gear and the housing, which must be very exact and varies from application to application.”

“Furthermore, on every distributor shaft, where the advance weights are on the shaft, we make sure there is a smooth rotation of the weights,” continued Davis. “We’re unique in that we set and curve the weights on a distributor machine, which lets the mechanical and vacuum advance work together in the finished product. And since we can set the timing curve from idle all the way through the RPM range, this gets us a smooth timing curve.”

To attain a proper advance curve, Performance Distributors spins the DUIs on a special machine. It does this for both mechanical and vacuum advance curves. It ends with a test firing session that takes just a few minutes. Then it gets shipped out to the customer.

What It All Comes Down To

Every classic vehicle deserves a second chance, and part of that redemption is making sure the ignition is up to the challenge. As we’ve seen, the DUI is instrumental in not only providing ample spark to the plugs, but also keeping its internals safe from outside harm, thanks to a well-designed and durable housing.

Rounding out the package are LiveWires, which can be purchased with a DUI. These wires ensure that low-resistance, high-voltage spark reaches the plugs. And speaking of plugs, it’s nice to know that all that extra voltage means a user can run higher gap widths and create a better, more powerful combustion.

Currently, Performance Distributors offers DUIs and LiveWires for a wide variety of applications. Classic Ford, GM, Mopar, Toyota, and even Volkswagen owners can all equip their engines with a distributor worthy of their trust. We encourage you to check out more by visiting Performance Distributors’ website, and don’t forget to follow them on Facebook, too.

Article Sources

About the author

David Chick

David Chick comes to us ready for adventure. With passions that span clean and fast Corvettes all the way to down and dirty off-road vehicles (just ask him about his dream Jurassic Park Explorer), David's eclectic tastes lend well to his multiple automotive writing passions.
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