Some time ago, a member here recommended that I run the NGK R5674-7 plugs in mu car. Seeing that the seat type and heat range matched I didn't bother to check anything else and have been running them seemingly fine ever since.

Now my question is, I noticed everywhere has these plugs listed as a non resistor type. I thought non resistor plugs were a no-no except for basically track cars with non computerized carb'd motors.

How is it that all this time I have been able to run non resistor plugs with a TPI motor and an amped stereo system with no noticeable side effects?

 

a resistor plug helps to reduce spark gap radio interference. you would only really notice a difference if you were listening to AM radio. i don't think that non resistor spark plugs are legal for road use, but im not sure.

 

As well as reducing electrical noise for radio, television and mobile telephones etc, many modern ignition systems require resistor plugs to stop electrical noise from interfering with the vehicle's on-board electronic control units (ECUs). If non-resistor plugs are used in place of resistor ones, the result can be malfunction and in some cases immobilisation of the vehicle. Resistor spark plugs should always be fitted, therefore, where specified. NGK resistor spark plugs contain a single ceramic monolythic resistor of approximately 5000 ohms. Because of the type and construction of the resistor (ie no springs), the problems of vibration and sudden changes in temperature that can occur with some other brands do not apply. The function of the resistor is to reduce electrical noise generated by the ignition system. The most effective place to situate a resistor in the high tension circuit is as close to the spark plug as possible. This makes the spark plug an ideal place to house the resistor. Because the resistance value is only approximately 5000 ohms, there is no detrimental effect on engine performance, power output, vehicle emissions etc. It is also a fact that many motor sport world champions only use NGK resistor spark plugs. In nearly all cases - apart from some very old low output ignition systems - resistor spark plugs can be used in place of the non resistor versions

 

i don't think that non resistor spark plugs are legal for road use, but im not sure.
Z28romance, Really? I'm sorry, but I wish people would research things before they miss lead someone.

 

really. being that i included "im not sure" in that statement, i dont think any one would take that statement as lore. in my past employment life as an RF CATV technician i had to read volumes of FCC regulations. you wouldn't believe what the FCC's purview covers. any and all electronic devices that may emit radio interferience falls under their guidelines. this would include vehicle ignition systems.

 

z28romance is correct. I contacted NGK tech support and they said the exact same thing right down to the ohmage of the resistor.

Regarding legality use, my car is already a rolling federal offense so I'm not too concerned about 8 little spark plugs being legal

 

I can say this, I used ar133's in my sbc, (which is a non resister racing plug) and it caused all sorts of interference in not only my radio, but also my innnovate wideband.
Swapped to a resister plug and issues were gone.

 

I know a little about the FCC too. 33 yrs with the same telecom company. That doesn't matter. It's just that lately we've been reading alot if misinformation on these threads. There are a lot of members new and old that look for reliable info to apply to their problems. The info you provided on the noise of non resistor and resistor plugs was useful. We just don't want them to think they could be doing something illegal, some have to have their cars inspected for registration, that's all.

 

Which is why he ended the post with, "I'm not sure". Leaving it up to the reader to do the research and figure out whether or not It's legal. If they don't bother to look it up given the "fact of the fact", then that's their fault.

Seriously, get off the dude's back. Nothing was said out of line here.