ARC-2 Asynchronous Restriking CDI -
2
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Introduction
Thank you for purchasing the Dynatek ARC-2 Ignition. Please take a few moments and read through all of the installation
information before attempting to install this. If this is being installed on a vehicle which we make a plug in harness for, we highly
suggest you use that harness. Consult the Installation Guide included with that harness for vehicle specific installations. If you
have any more questions, please consult your Dynatek dealer before installation.
The ARC-2 ignition was designed with several key technologies that enable it to optimize your vehicles ignition system, and
realizing the performance potential of your vehicles engine. The design features that help to do this were how the ARC-2 was
named – Asynchronously Restriking CDI – 2 channel.
The Asynchronous firing allows you to run the 2 channels independently. Each channel has its own storage capacitor. This
allows the ARC to fire the 2 channels simultaneously, or nearly simultaneously. This is necessary in applications where there
are leading and trailing spark plugs firing close together.
The Restriking fires off lean mixtures at idle and low RPMs. Restriking will fire the spark plug multiple times at low RPMS,
so that if the mixture did not light the first time, it will be ignited the second time, ensuring that the combustion occurs. The
ARC uses ISP (Intelligent Spark Profiling) to speed up the second and later sparks. This ensures that the second spark on
the ARC occurs sooner than would otherwise be possible.
The Capacitive Discharge Ignition design produces a short duration high intensity spark, with a profile designed to ignite
under the most severe conditions. This high voltage and intensity makes the spark more likely to ignite on high power appli-
cations like high compression, turbocharged, and/or nitrous equipped vehicles.
It is also ideally suited for high RPM use, where the zero dwell time means it will have full power to much higher RPM than
possible with most coils.
Pre Installation
Basics of CDI vs. Inductive ignition
There are two commonly used types of ignition on the market today: Capacitive Discharge, and Inductive. They have funda-
mental differences not only in how they work, but also in how they are wired.
Inductive Ignitions are very common in factory applications.
They require fewer parts, and are cheaper to build. They work by
storing energy in the ignition coil. It draws 12V from the battery,
through the ignition coil on the primary side, and then to the ECU
(or to a power transistor) as shown in Figure 1(a). This current
builds up a magnetic field within the coil. To create the spark, the
current is stopped. This causes the magnetic field to collapse,
and creates the voltage spike on the secondary that starts the
spark. See Figure 1(b).
The coil resistance and inductance are very important on
Inductive Ignitions. The amount of time the coil is being charged
with current by the ECU is often referred to as the dwell time.
How much current is needed, and how quickly the current flow
rises is directly related to the coil resistance and inductance. In
an Inductive Ignition system, mismatching your coils to the dwell
time the ECU gives could result in either too weak of a signal to
create a spark, or too much current that could damage the ECU,
coils, or both. Also, the total amount of energy that can be
produced from the ignition is going to be a function of the dwell
time, and inductance of the coil. With a large inductance, the
dwell time will have to be very long, but you can store more total
energy. A small inductance allows the current and energy storage
to build very quickly, but it has much less total energy storage
capacity.
