PeachParts Mercedes-Benz Forum - View Single Post - Spark Plugs: Resistor vs. Non-Resistor

oldtrucker · #57 11-14-2014, 05:58 PM

Guess I always should make a copy to the clipboard, before leaving down the hall. If not that's a good way to lose the reply.

With that said, I agree with comm-tech Karl.
The resistor in the spark wire, plug or elsewhere in the ignition system was developed from the need of RF or Electromagnetic Field suppression.
With the increase of wireless, computer and essentially millions of wireless remote controlled devices, the need of noise suppression exists and won't go waway.
A spark can create harmonics that reach into the SHF spectrum (Cell Phones and more).

In whichever form suppression may be, it must be there to allow those other devices to work properly.
By changing the design, you may introduce more noise into the environment and thereby cause (not always apparent) more problems or simply mess with performance of your vehicle.

Bottom line:
Spark plugs that contain resistors, should only be used in vehicles that were designed for it.
A vehicle that was designed for non-resistor spark plugs, should only get the proper non-resistor plugs.

One can study the design and alter it so that resistor plugs can be used, but I think you would throw money into the pit.

With the newer systems, unfortunately, I am not up to spiff, I could imagine that there is some inductance and/or capacitance, playing some role to make it more efficient.
Remember that capacitor in older point contact ignition systems, it was there to suppress the arc across the points. When left out of the system, it would still work, but burn the contacts in no time and one could hear the vehicle coming 1/2 mile away, in an AM radio.

Depending on age of the vehicle, I mean very old, it may make sense to put in some suppressor, but may also decrease performance of the engine.
Many answers to the questions, are depending on ignition system design and age.
If there is a performance increase by using different types of sparkplugs, I believe it is so insignificant and probably surfaces only during a dyno test. Remember, most every 90's and later vehicle has some sort of fuel delivery system that want's to close a loop!