Spiro-Core "MAG" wire

for European Ignition Systems

karlyn bremi ignition wire sets

Why do Ignition leads have resistance?

Ignition Cable Sets have resistance to prevent radio frequency noise from interfering with radios, cellular telephones, computers and other onboard electronic equipment. European ignition systems are designed around exact OHM and Voltage values to provide the optimum balance between:

  • Maximum Fuel Efficiency
  • Maximum Engine Power
  • Minimum Radio Frequency Noise
  • Minimum amount of harmful constituents in the exhaust

Each lead in a European wire set must have the exact same resistance +/- 10% of a specific value which is unique to the Ignition System. Since each lead of a wire set has a different length, this can only be achieved by using copper wire (no resistance) with specific value resistorized ends. STI makes European wire sets according to O.E. drawings with 19-strands of tinned copper wire and exact resistorized ends. The correct resistance values can not be achieved with Spiro-Core wire!

What is Spiro-Core Wire?

Spiro-Core is an upgrade from basic resistor wire. It is made by wrapping a thin metal strand around a non-metallic core. This reduces the resistance in the wire from somewhere between 3000-7000 OHMS per Foot in basic resistor wire to under 1000 OHMS per Foot, while still being able to prevent a good amount of Radio Frequency Noise. This wire was designed for applications whose performance is not based on exact ohm values like most American and Japanese applications. The resistance is built into the wire and the overall resistance varies proportionally to the length of the wire.

Why would anyone make a European wire set with Spiro-Core Wire?

A) O.E. Resistorized connectors are expensive and there are many different types that are needed if you plan to offer an entire wire set line. Some manufacturers try to circumvent this by replacing the O.E. connectors with hollow look-a-like non-resistorized connectors. Then they use Spiro-Core wire to try to make up for some of the lost resistance. What the purchaser of such a set does not see is that while they may be paying less for a set that looks like the real thing, they just sacrificed the performance of their “European driving machine”.

B) Manufacturers of such gimmick devices as multi-spark ignition, high energy coils etc. are trying
to tell the public that they are smarter than the European engineers. While proof of their claims is suspect, one thing is for sure. If you use an O.E. type wire set with their high energy gadgets, you
will ruin the O.E. resistorized connectors. Knowing this, these manufacturers must use hollow
non-resistorized connectors. Then they use Spiro-Core wire to try to make up for some of the lost resistance.

So, What happens when you use Non O.E. Type wire sets (ie. Spiro-Core)?

1) Highly engineered European Control Systems recognize the incorrect resistance values, and variations of resistance between the Cylinders of Spiro-Core wire sets. The Control System then perceives this deviation from the norm as a problem, and tries to compensate for it. Hence, your car may not run to it’s highest efficiency with Spiro-Core wire and you could also be limiting the life of your Control System because of it’s constant need to overcompensate.

2) Since Spiro-Core wire cannot reach the OHM values or the R.F.I. filtering capabilities specified by European Ignition Systems, the radio, cellular phones or other onboard electronic equipment may be adversely effected.

3) European cars have many systems of microcontrollers that are used in a wide range of vehicle applications involving engine control, convenience and comfort. Each system must meet specific EMI (Electromagnetic Interference) standards, which is dependent upon it’s Capacitance, Inductance and Resistance values. The allowed EMI for each system is designed so that it will work in harmony with every other system. This is critical, cause EMI problems can cause a car’s brakes to lock, gears to automatically shift, airbags to fire, doors to lock or the engine to mysteriously shut down, This is the same phenomenon that affects hospital equipment and aircraft instruments. By changing your ignition cable set to something other than an O.E. type wire set, you are altering the EMI characteristics specified by the manufacturer. This could result in damage due to electromagnetic interference. According to BMW of North America, A specific repair would not be covered under warranty if it were determined that damage was caused by the installation of any non-approved after market component.

3) STI’s resistorized connectors are hermetically sealed with an epoxy resin and then encapsulated with the highest grade silicone. Our connectors are water tight and thermally stable. The standards by which STI’s O.E. type connectors are designed, produced and tested by are as follows:

  • EMI (Electromagnetic Interference) Test
  • Temperature Resistance Test
  • Vibration Resistance Test
  • High Voltage Protection Test
  • Oil Resistance Test
  • Corrosion Resistance Test
  • Temperature Shock Test
  • Voltage Leakage (Salt Water Bath) Test
  • Voltage Interference Test
  • Engage/Disengagement Force to Plug Test
  • Connector to Cable Holding Force Test

Spiro-Core wire sets don’t claim to use O.E. ends and therefore do not have to meet these standards. They use a hollow boot with a terminal that’s crimped on the wire. Therefore, they cannot prevent performance deterioration due to voltage leaks, corrosion, vibration and poor contact like an O.E. type wire set can.

In Summary

Highly engineered ignition systems require components to perform exactly like they were designed to.
For optimum engine performance you can’t do better than STI’s OEM TYPE WIRE SETS.