Resistor vs Non-resistor plugs?

[JohnJL]

I went to the store armed with the recommendation from this board for NGK BPR6ES plugs for my 2.7 Weber-carbed lump. The guy brought back BP6ES, which I sent back and asked him to find the R's. He eventually did, but that got me thinking...whats's the difference in function and application?

Saw lots of mentions of both but no explanation and its not on NGK's site that I could find.

thanks

[ljowdy]

NGK site says this

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

[JohnJL]

Thanks, dont know how I missed that on the site...

[RoninLB]

i use NGK R all the time.

no difference in carbon loading.

[ttweed]

Most of the vendors around here do not even stock non-resistor plugs anymore, I have found. The proliferation of modern electronics in today's cars, I guess....

TT