MSD’s Newest 6AL Takes Conventional Ignitions into the Digital Age

These days, we live in a purely digital world. From books, board games, and mail, to newspapers, music, and even the magazine that you’re reading right now. But we’re not talking just entertainment and daily amenities here. Every element of your vehicle – with the exception of maybe the cup holder – is already or soon will be controlled via digital electronics.

Race cars, street cars; you name it. Recently, powerTV acquired a well aged Fox body Mustang – packing a supercharged punch under the hood – and one of our goals was to bring the ignition system up to the most modern of standards. Because while little has changed in the 150-plus years since the invention of the spark plug, how we control it is a technology that is continually in development. The car currently utilizes an MSD 6AL ignition box combined with an MSD-manufactured boost timing box supplied by supercharger maker Vortech that controls the boost/timing retard of a turbocharger or supercharger.

But this update isn’t for just Mustangs – any engine that can support a MSD 6AL box can reap the benefits of this upgrade. That means if you have a points, magnetic pickup, TFI, HEI or crank trigger-type ignition, the new MSD Digital 6AL can work for you!

Once the decision was made to upgrade our ignition system, we again turned to MSD, who supplied us with one of their latest and greatest pieces and the second generation of the 6AL: the MSD Digital 6AL. Because we’re continuing the use of the MSD/Vortech boost controller, we’ll retain all of the same functionality as our 6AL setup, but with all of the advantages that come with today’s digital ignition control modules.

In order to pinpoint some of those advantages and learn the differences between standard electronic and digital ignitions, we’re going to compare the new Digital 6AL alongside its older brother, the non-digital 6AL.  To provide some extra insight into these two generations of MSD units, we spoke with MSD Marketing Specialist Kyle Neisen to help us in our look at these two boxes.

RPM Control At Your Finger Tips

Tucked away in a stealth-like manner on the Digital 6AL is a set of rotary dials for fine tuning the RPM rev limiter, doing away with the inconvenient chip modules of the former 6AL.

One of the first things you’ll notice when you take the Digital 6AL out of the box are the rotary dials tucked away in a stealth-like manner atop the box. The 6AL required the use of RPM modules, which came in 3,000, 6,000, 7,000, and 8,000 RPM ranges with others available to be plugged into the ignition box to set your rev limiter. MSD’s Kyle Neisen explained, “instead of having multiple different chips to plug into it, you have the rotary dials where you can just set it and forget it. Or if you need to, you don’t have to rummage around for the pills; you just set it right there on the box. This has been very popular with our customers that we’ve spoken to so far.”

If you’ve ever misplaced or forgotten that you loaned one or more of your RPM chips to a buddy and needed to make a quick adjustment, you’ve probably found yourself in quite the pickle. Not so with the Digital 6AL. Rev limiter adjustments are right there under the dash, just a turn of the dials away and ready to adjust in just seconds and on the spot in 100 RPM increments.

Digital Efficiency

The new Digital 6AL has a slightly smaller form factor than the previous 6AL, and at an increased 530 volts and 135 millijoules of output at a lower power requirement, delivers even more power for supercharged and turbocharged applications.

Enthusiasts are continually squeezing more and more horsepower from their engines through the use of superchargers, turbochargers, and nitrous oxide. But these combinations demand increased spark output, and for many years, the blue oval faithful flocked to the 6AL and its 480 volts and 115 millijoules of spark energy that could meet the demands of their performance upgrades. But like anything, it was only a matter of time before the 6AL was improved upon. The Digital 6AL delivered by producing an increased 530 volts and 135 millijoules of output. And it does so at a lower power requirement at just 0.7 amps per 1,000 RPM’s compared to the 1.0 amps per 1,000 RPM of the 6AL. More juice is always a good thing.

MSD Digital 6AL Highlights – PN 6425

• Integrated rotary dials eliminates the need for pills
• Same mounting foot print as the previous 6AL
• Weather-proof connector utilizes some wire color coding has previous generations
• Must use new digital two step box – not compatible with older pill-style versions
135-145 mJ per spark — 115 mJ on previous 6AL
• Primary voltage of 520-540 Volts – 480 Volts on previous 6AL
• Secondary Voltage of 45,000 Volts
• Works up to 15,000 RPM with 14.4 volts
• Current draw of .7 amp per 1,000 rpm – 1.0 am per 1,000 rpm with previous 6AL

Wiring and Installation

One of the best features of the Digital 6AL is the new sealed and locking connector that makes quick and easy removal of the entire warning harness a snap...literally.

When viewing the wiring diagram for the 6AL and Digital 6AL, you’ll notice they share a striking resemblance to one another. Neisen points out that the primary, or rather, only, difference between the two is the sealed and locked connector on the new model that routes all of your wires out of one side of the module with one simple connector. Thus, if for any reason you need to remove the module from the car, the connections will snap right back in and you’re ready to go.

From the factory, the Fox body Mustang’s 302 engine and ignition system utilize what is known as a magnetic pickup trigger. Up until late models cars began shipping with distributor less ignition systems, these were quite common. A wire wrapped around a magnet creates a magnetic field, and when this field changes, due to another metal object coming into the field, a voltage is generated and is used as the trigger signal for the ignition box.

Our new Digital 6AL installs under the dash in the same location that housed the 6AL.

In the case of the MSD Digital 6AL, the magnetic trigger from either the distributor or a crank trigger wheel connects to the ignition box via the green (-) and violet (+) wires. The Ford coil connects to the ignition box through a single red connector, while the heavy red (+) and heavy black (-) wires source power from the battery. Your orange and black wires connect the MSD Blaster 2 or other coil to the box. The Digital 6AL mounts in the same location under the dash that our 6-BTM was located, and from there it’s essentially a plug-and-play installation.  Explained Neisen “as far as the signal input, the two boxes are identical. You have either the mag input, which are the violet and green wires, or the points input, which is the white wire.”

For other types of ignitions, check out MSD’s wiring diagrams.

The wiring diagram for our Digital 6AL using a magnetic pickup and MSD's Blaster SS coil.

Boost Timing Master

For anyone whose ever built and/or tuned a boosted combination, you know retarding of the ignition is necessary, with the amount dependent on factors such as the octane rating of the fuel and compression ratio. Generally, around one degree per pound of boost is a good starting point. This is where the Boost Timing Master comes in to play.

We've reused the MSD-manufactured Vortech Boost Timing Master (blue box at top) in conjunction with our new Digital 6AL to control the ignition retard as boost levels increase.

The Vortech Boost Timing Master, a a semi private-labeled version of MSD’s own Universal Boost Timing Master, acts to retard the ignition as the boost levels increase. The timing may be retarded up to a maximum of 15 degrees in increments of 1, 2, or 3 degrees per pound of boost. A boost pressure point can also be specified as the starting point for the degrees of retard. Thus, you could specify 0 retard for up to 3 pounds, or 2 degrees per pound up to 10.5 pounds.

Our completed installation of the Digital 6AL. Note the MSD Blaster SS coil that we're utilizing mounted on the left shock tower.

The limits to which automotive enthusiasts will push the envelope on performance are derived only by the technology that they can get their hands on. For companies like MSD, their money is earned by continually developing and advancing ignition and spark technology to once unthinkable heights. With the Digital 6AL, MSD has taken the blueprints for what was already an impressive ignition box and created even more power capability on less draw, with new features that make ignition tuning and adjustments easier than they’ve ever been. And combined with the Boost Timing Master, you’ve got a combination that’s hard to beat.

About the author

Andrew Wolf

Andrew has been involved in motorsports from a very young age. Over the years, he has photographed several major auto racing events, sports, news journalism, portraiture, and everything in between. After working with the Power Automedia staff for some time on a freelance basis, Andrew joined the team in 2010.
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