Resistors in spark plugs

[Rich@rdS]

Just wanted to find out if there were any differences in spark plug performance between plugs with resistors and without. Are they perfectly interchangable without negative effects, like reduced spark performance or something?

My Pug specifies Bosch H6DC plugs, but I've just bought HR6DC plugs with the internal resistors. I do know that the resistors are there for noise suppression purposes. Why would manufacturers bother producing plugs without the resistors if there were no disadvantages to using the resistive types?

cheers!
Richard

 

[Rich@rdS]

I guess nobody knows...?

 

[CHRI'S16]

....mate im not sure either. The resistor could also be for heat ranging. Or to prevent excessive arking thus prolong life?? but only guessing.
Ultimately as long as the condition, gap and heat range are correct then that leaves little else to be overly fiddled with really. - chris

 

[dino]

Resistor
At the moment the spark jumps the gap it causes a high frequency burst of energy, this is known as RFI (radio frequency interference). This is why resistor spark plugs were introduced in the mid 1960's. Placing a resistor within the spark plug suppresses the RFI. Without resistor plugs in your car you can experience static on your radio as well as interfere with other sensitive electronic equipment. Some later model vehicles as well as newer Powersport engines must use resistor plugs for a proper "talkback" to the electronic ignition. Outboard marine Capacitive Discharge Ignition (CDI) such as used on some Johnson and Evinrude marine engines require a special inductive type resistor (such as a Champion Q-type or NGK Z-type). Use of non-inductive resistor type plugs on these motors can cause misfire and poor performance.
For automotive CDI high output ignition systems systems (such as Mallory, MSD, Crane and Accel), refer to Resistor plugs for race engines for information relative to modified motors.\

i ve cut and pasted this of the sparkplugs.com site........there is more info there....most sparkplug manufacturers sites are a great read...very educational.....ie advancing timing...colder or hotter plug???

hope it helps

cheers
dino

 

[Rich@rdS]

Thanks for the info guys, yeah I did some googling and found heaps of info on resistive plugs. Seems most new cars use them because of the sensitive electronics and computers now on board of these cars.

Also seem to produce a negligible amount of power loss (if any) by using them, so I might switch over to them permanently as I do have a computer hiding under my dash somewhere.

Anything that might produce an extra couple of kW here or there... roll_lau

Cheers,
Richard