Driving Under the Influence
(of Davis Unified Ignition)

By Jack Brinks

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DUIOk, now on to the LiveWires.  Since the distributor cap is much larger than stock, please be patient when installing the plug wires, as it may be a bit of a challenge clearing everything in the way.  I had to slightly relocate my fuel supply line and fuel filter, but that’s all.  Don’t forget to put the supplied dielectric grease on the terminals at each end of the plug wire.  It helps to water-proof the terminals and allows much easier removal in the future.

In my humble opinion, it’s easiest to start with the #1 wire and go around the cap in firing order direction.  In this case, that’s clockwise (not all applications are, depending on distributor location, either front/rear or left/right!)  Connect each wire to the distributor cap, laying it across the engine and pointing towards the cylinder it goes to.  Since each LiveWire is marked with the corresponding cylinder number, it’s very easy to finish the job by connecting the spark plug terminal end.  Once this is done, complete the install by installing the Billet Aluminum Wire Looms.  Check out the photos. Not only are they functional, they look absolutely awesome too!



Last, but certainly not least, we need to set our initial timing.  If you installed the distributor properly, the engine should fire right up.  You may have to turn the distributor housing slightly to get it started, but that’s all. 

If you don’t have a timing light, you’ll need to borrow one, or buy one.  Connect the power leads to the battery, and the spark pick-up lead to the #1 cylinder spark plug wire, making sure none of the wires are in harm’s way.  Performance Distributors recommends starting at the OEM spec, which is 5 degrees BTDC (Before Top Dead Center) on my 401.   Next, disconnect (if not already) the vacuum hose at the distributor vacuum advance, and plug it.  I keep a small supply of golf tees around just for this.  After the engine has warmed up, set the engine RPM down to 600 or so, and check the timing.  Rotate the distributor housing to obtain your OEM setting, shut off the engine, and then tighten the distributor hold down clamp bolt  Recheck the timing, plug in the vacuum hose, and reset the idle speed to factory specifications.  This will vary a bit from one engine to another, also depending on transmission type.  OK, start the engine and let’s go for a test drive!

Performance Distributors recommends setting your initial timing to 12 degrees advanced (BTDC) for racing and off-road conditions.  Since this timing setting does effect emissions, you may not be able to go this far.  However, within reason, the more advance you can put in without pinging (pre-ignition) will increase horsepower and fuel economy.  Since that “pinging” sound you hear is actually pre-ignition and the pistons slapping in the cylinder walls, this is a case where too much is not a good thing.  That’s why a little “pre-testing” is in order.  After warming up the engine again, go for a test drive and, using the timing procedure above, move up the timing a little at a time until you get a little ping on heavy acceleration.  My suggestion is accelerating hard in a higher gear, but not hard enough to downshift the transmission (if it’s an automatic).  A little ping under these conditions will be OK, but not much.  My testing revealed my engine performed very well at around 9 degrees. Yours may vary a little, depending on compression ratio, etc.  My 401 is at 10:1 compression - higher than most. 

Once you’ve got it dialed in, it’s time to really test this new DUI setup.  The first thing I noticed was much easier starting.  I have a habit of cranking the engine a bit before pumping the accelerator (it’s got a carb, remember?) to create a little oil pressure, since my Jeep sometimes sits for up to two weeks without moving.  The first time I did that, since it was cooler out and the choke kicked in, the engine actually started without me pumping the gas pedal.  It’s never done that before!

Testing on-road revealed smoother idling, and improved performance on acceleration, as well.  I can’t really say just how much improvement the DUI setup has made, but it has definitely “woke up” my engine!  The performance at just off idle is much better, with absolutely no hesitation like the old setup.  In fact, I can spin my recently installed 42” Super Swampers on the concrete, much to the chagrin of my neighbors!

Off-road testing was conducted initially at the Superlift At the Mountain event at Barnwell Mountain Recreation Area (BMRA) held over Veteran’s Day weekend.  (Check out for more info. Put this event on your calendar for that weekend next year. You’ll have a great time!)  Since I’m the Trail Boss for this event, I didn’t get much real trail time in, but I sure did a lot of running back and forth through the park.  During the little trail running I did do, I noticed that my engine seemed to have less tendency to stall when crawling at very low speeds over rocks and ledges. Definitely a good thing! 

The real off-road test came over Thanksgiving weekend during a trip to Clayton, Oklahoma.  This was the first time out with my new/used larger tires.  Clayton is probably my most favorite wheelin’ place.  It’s fairly close (under four hours away) for me, and between Green Acres (just outside of town), Frieling’s Land (about 15 miles NE of town), and the trails three miles south of town, there’s something for everyone. 



My new favorite trail has got to be Black Sheep Boulevard at Green Acres.  This ‘X’ rated trail is not extremely hard for big-tired rigs, but it is challenging.  The entrance is somewhat intimidating, but actually fairly easy when it’s dry.  Only three rigs attempted the trail, and we all completed it with no breakage or winching, but it was a great workout for my taller and a little narrower rig, really putting every aspect of it to the test.    



The Davis Unified Ignition system performed flawlessly, whether the Jeep was nearly on its side or pointing to the sky.  I’m certainly happy with this upgrade, and have no reason to expect it won’t continue to work flawlessly for years to come.  It has definitely simplified that part of my rig, and if I’ve learned nothing over the years, I’ve learned simple is good!

If you’re looking to upgrade the ignition system on your rig, call Performance Distributors at (901) 396-5782 or email them at  You’ll be dealing with good folks who build quality stuff, and, they’ll shoot you straight!



Performance Distributors
2699 Barris Drive
Memphis, TN 38132
(901) 396-5782


Jack Brinks

Jack Brinks is an avid four-wheeler and a contributor here at Jack's a Texan and frequents many events in the Southwest.

Contact Jack at

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