I never heard that in my life.
http://www.magnecor.com/magnecor1/truth.htm
"CAPACITOR" EFFECT WIRES with grounded metal braiding over jacket
The most notable of exaggerated claims for ignition wires are made by Nology, a manufacturer of ignition wires promoted as "the only spark plug wires with built-in capacitor." Nology's "HotWires" (called "Plasma Leads" in the UK) consist of unsuppressed solid metal or spiral conductor ignition wires over which braided metal sleeves are partially fitted. The braided metal sleeves are grounded via straps formed from part of the braiding. Insulating covers are fitted over the braided metal sleeves. These wires are well constructed. For whatever reason, Nology specifies that non-resistor spark plugs need to be used with their "HotWires." In a demonstration, the use of resistor plugs with "HotWires" will nullify the visual effect of the brighter spark.
Ignition wires with grounded braided metal sleeves over the cable have come and gone all over the world for (at least) the last 30 years, and similar wires were used over 20 years ago by a few car makers to solve cross-firing problems on early fuel injected engines and RFI problems on fiberglass bodied cars — only to find other problems were created. The recent Circle Track Magazine (USA, May, 1996 issue) test showed Nology "HotWires" produced no additional horsepower (the test actually showed a 10 horsepower decrease when compared to stock carbon conductor wires).
The perceived effect a brighter spark, conducted by an ignition wire, encased or partially encased in a braided metal sleeve (shield) grounded to the engine, jumping across a huge free-air gap (which bears no relationship to the spark needed to fire the variable air/fuel mixture under pressure in a combustion chamber) is continually being re-discovered and cleverly demonstrated by marketers who convince themselves there's monetary value in such a bright spark, and all sorts of wild, completely un-provable claims are made for this phenomena.
Like many in the past, Nology cleverly demonstrates a brighter free-air spark containing useless flash-over created by the crude "capacitor" (effect) of this style of wire. In reality, the bright spark has no more useful energy to fire a variable compressed air/fuel mixture than the clean spark you would see in a similar demonstration using any good carbon conductor wire. What is happening in such a demonstration is the coil output is being unnecessarily boosted to additionally supply spark energy that is induced (and wasted) into the grounded braided metal sleeve around the ignition wire's jacket. To test the validity of this statement, ask the Nology demonstrator to disconnect the ground strap and observe just how much energy is sparking to ground.
Claims by Nology of their "HotWires" creating sparks that are "300 times more powerful," reaching temperatures of "100,000 to 150,000 degrees F" (more than enough to melt spark plug electrodes), spark durations of "4 billionths of a second" (spark duration is controlled by the ignition system itself) and currents of "1,000 amperes" magically evolving in "capacitors" allegedly "built-in" to the ignition wires are as ridiculous as the data and the depiction of sparks in photographs used in advertising material and the price asked for these wires! Most stock ignition primaries are regulated to 6 amperes and the most powerful race ignition to no more than 40 amperes at 12,000 RPM.
It is common knowledge amongst automotive electrical engineers that it is unwise to use ignition wires fitted with grounded braided metal sleeves fitted over ignition cable jackets on an automobile engine. This type of ignition wires forces its cable jackets to become an unsuitable dielectric for a crude capacitor (effect) between the conductor and the braided metal sleeves. While the wires function normally when first fitted, the cable jackets soon break down as a dielectric, and progressively more spark energy is induced from the conductors (though the cable jackets) into the grounded metal sleeves, causing the ignition coil to unnecessarily output more energy to fire both the spark plug gaps and the additional energy lost via the braided metal sleeves. Often this situation leads to ignition coil and control unit overload failures. It should be noted that it is dangerous to use this style of wires if not grounded to the engine with grounding straps, as the outside of the braided cables will be alive with thousands of volts wanting to ground-out to anything (or anybody) nearby.
Unless you are prepared to accept poorly suppressed ignition wires that fail sooner than any other type of ignition wires and stretch your ignition system to the limit, and have an engine with no electronic management system and/or exhaust emission controls, it's best not to be influenced by the exaggerated claims, and some vested-interest journalists', resellers' and installers' perception an engine has more power after Nology wires are fitted. Often, after replacing deteriorated wires, any new ignition wires make an engine run better.
