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Tech Info » Wire Set FAQ

Q: What is a variable pitch wire?

A: NGK uses a variable pitch wire to create the resistance necessary to filter RFI created by an operating ignition system. The variable pitch system alternates tightly wound and loosely wound copper wire around the center of the plug wire to create a magnetic field, creating the necessary resistance with a fraction of the impedance found in a solid carbon core type wire set.


Q: What is RFI?

A: Radio Frequency Interference (RFI) or electrical "noise" is caused by ignition systems, alternators, wiper motors, etc., but the ignition system causes the strongest "noises" and they include a wide range of frequencies. This noise can cause interference with the operation of radios, electronic components, fuel injection systems, depth finders, and other sensitive electronic equipment. Resistor plugs, wires and spark plug caps are used as a RFI suppression system to reduce this noise.


Q: Are NGK wires 8 mm?

A: NGK wires are manufactured to the specific dimensions of OEM wires. Most NGK wires are 7mm, while Toyota applications are 5mm where applicable. Most 8mm wires in the aftermarket are merely providing additional insulation, and do not increase the electrical capabilities of the ignition system.


Q: Are NGK wire sets universal?

A: NGK wire sets are custom manufactured to the exact dimensions of the application. There are no universal sets. Additionally, each individual NGK wire is labeled for the particular cylinder number for virtually fool-proof installation.