INSTALLATION INSTRUCTIONS
AUTOTRONIC CONTROLS CORPORATION
• 1490 HENRY BRENNAN DR., EL PASO, TEXAS 79936 • (915) 857-5200 • FAX (915) 857-3344
MSD Digital 6 Plus Ignition Control, PN 6520
Parts Included:
1 - MSD Ignition
1 - Harness, PN 8860
1 - Parts Bag, ASY 19864
WARNING: During installation, disconnect the battery cables. When disconnecting the battery always
remove the Negative cable first and install it last.
Note: Solid Core spark plug wires cannot be used with an MSD Ignition.
LED INDICATOR
There is an LED that monitors the status of the Ignition. The LED monitors several parameters of
the ignition including trigger signal, low voltage and high voltage.
OPERATION AND FEATURES
Note: Do not use digital or dial back timing lights.
DIGITAL OPERATION
The MSD Digital 6 Plus uses a high speed RISC microcontroller to control the ignition’s output
while constantly analyzing the various inputs such as supply voltage, trigger signals and rpm. The
high speed controller can make extremely quick compensations to the output voltage, multiple
spark series, timing and rpm limits while maintaining accurate timing signals to within 1° and 1%
of the rpm limits. The circuits and controller of the Digital 6 Plus have been thoroughly debounced
and isolated to create protection against Electro Magnetic Interference (EMI).
CAPACITIVE DISCHARGE
The MSD Digital 6 Plus features a capacitive discharge ignition design. The majority of stock
ignition systems are inductive ignitions. In an inductive ignition, the coil must store and step up
the voltage to maximum strength in between each firing. At higher rpm, since there is less time to
charge the coil to full capacity, the voltage falls short of reaching maximum energy which results
in a loss of power or top end miss.
The MSD Ignition features a capacitor which is quickly charged with 520 - 535 volts and stores
it until the ignition is triggered. With the CD design, the voltage sent to the coil is always at full
power even at high rpm.
MULTIPLE SPARKS
The MSD produces full power multiple sparks for each firing of a plug. The number of multiple
sparks that occur decreases as rpm increases, however the spark series always lasts for 20° of
crankshaft rotation. Above 3,300 rpm there is simply not enough “time” to fire the spark plug more
than once, so there is only one powerful spark.
PROTECTION
The MSD Digital 6 Plus has a built in reverse polarity protection circuit. This will protect the ignition
in the event of wrong connections. It will also shut off for protection from a surge in power. The
ignition will still operate once the surge or polarity is corrected.
