Electrical devices, including spark plugs, use only the electrical energy necessary to perform the
function for which such devices are designed. Spark plug wires are nothing more than conductors, and
whereas a bad ignition wire's inefficient conductor can reduce the flow of electricity to the spark plug, an
ignition wire that reportedly generates an "increase" in spark energy will have no effect on the spark
jumping across the spark plug gap, since the energy consumed at the spark plug gap won't be any more
than what is needed to jump the gap. For a more obvious example of this, a 25watt light bulb won't use
any more energy or produce any more light if it's screwed into a socket wired for a 1000watt bulb.”
Due to the extremely high energy in the
TECgt
coil charging circuit, spark plug wires may wear out
faster than with a standard ignition. As such, it is recommended that the wires be checked periodically for
carbon tracking caused by a breakdown of the internal conductor element. Looking at the plug wires in a
dark area and wetting them with a spray bottle of water will reveal carbon tracking. Pay close attention to
the exposed section of the spark plug (where the rubber boot ends) during the test. To maximize spark plug
wire life, keep the lengths as short as possible (i.e. mount the DFU as close to the engine as possible).
Replacement of the wires on an annual basis is recommended for high-rpm/high-horsepower applications.
For an extremely high-quality wire with excellent noise suppression, we recommend the Magnecor
brand. Specifically, their “Electrosports 80” 8mm wire is very good with our system. Custom wire lengths
and ends are available from them so you will not need to crimp the wires yourself. They can be reached at
(248)669-6688 or on the web at: www.magnecor.com . Taylor Pro-Wire Silicon Resistor wires also work
well.
C.9. Spark Plug Selection
As was previously stated, spark plugs are generally more important to spark quality than spark plug
wires. Most spark plugs exhibit failure when exposed to a large load. Failure usually consists of either
intermittent sparking or arc-over. Arc-over is when the spark occurs between the spark plug wire and the
engine block, instead of at the plug tip. Arc-over is exacerbated by the use of low-quality wires, or wires
that have cuts in the insulation.
The load at which a spark plug fails is different for all spark plugs. With the
TECgt’s
charging
circuit, the more load you put on an engine, then more voltage will be applied to the plug. This is a
beneficial situation: for a high compression engine, the voltage at the plug will be inherently higher (since
there is more load). The detriment is that spark plugs and wires are only rated to a certain voltage (30-
40,000 volts is typical), and can begin to “blow out” at around 40,000 volts. If that voltage is exceeded by
a large amount for a long enough length of time, the spark plugs will either blow out, break down or arc to
somewhere other than the electrode (often through the insulator directly to the engine block).
The solution is to run smaller plug gaps on high-compression engines. This is perfectly acceptable
with our ignition charging method, since the high load of the cylinder pressure will allow the voltage to be
quite high at the electrode, but the small gap will keep the plug from seeing an over-voltage situation. Use
the recommendations below as a guideline for spark plug gaps:
•
Stock
Street
Engine
0.045”-0.060”
(1.1mm-1.5mm)
•
High Performance Street
0.030”-0.035” (.75mm-.9mm)
•
Alcohol High Compression
0.025” (0.65mm)
•
High Power 75 -115 HP per Cylinder
0.025” (0.65mm)
•
Over 115 HP per Cylinder
0.022” (0.55mm)
•
Over 12:1 CR or Over 14psi Boost
0.022” (0.55mm)
Use of resistor plugs is highly recommended for optimum noise suppression. If using anything
other than a resistor spark plug wire, a resistor plug MUST be used. The bottom line is this: the
TECgt
system uses an
inductive
(long duration charge at battery voltage) charging method for the coils, which is
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TECgt Manual Version 2.0
- Page 49 -
©2008 Electromotive, Inc.