Understanding spark plug codes.
Instructor
Joined: Jan 2010
Posts: 109
Likes: 0
From: Caldwell Idaho
here is a good read...follow the internal links of the article.
http://www.ngk.com/charglossary.asp?...r+race+engines
c-ya
ToddG
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
From NGK Resistor plugs in Race Engines:
"As a rule, performance is in no way impaired by resistor spark plugs."
Wow I didn't know that. I recently changed from their "racing plug" to the same plug basically only it is a resistor plug because of my radio. I was a little hesitant to do so, but you learn something new every day
Actually I should post the whole thing, they do talk about high output CDI boxes but I think your runofthemill 6AL box isn't what they are talking about or I wonder what MSD specifies for it's 6AL box anyone know since we've been running them for 10 years or more ?
"Resistor plugs for race engines
It is strongly recommended resistor spark plugs be used in any motor that has on-board computer systems to monitor or control engine performance. Use of a non-resistor plug in certain applications can actually cause the engine to suffer undesirable side effects such as an erratic idle, high-rpm misfire, engine run-on, power drop off at certain rpm levels and abnormal combustion. Resistor plugs are also recommended on any vehicle that has other on-board electronic systems such as, two-way radios, GPS systems, depth finders or whenever recommended by the manufacturer.
If you have an outboard marine CDI (capacitive discharge ignition), (such as Johnson and Evinrude), make sure to use a plug with an inductive type resistor (such as a NGK Z-type). Inductive resistor plugs require less voltage than a monolithic (regular) resistor plug. Use of non-inductive resistor type plugs on these motors can create an open circuit within the spark plug (it will become a dead plug).
Mallory, MSD, Crane and Accel also produce a high output ignition CDI system, however, these should not be confused with a marine style CDI as mentioned above. For an automotive high output CDI system it is imperative you consult that manufacturer for plug specifications for their system. Some high out put systems specify the use of resistor plugs, while others will fry the internal plug resistor turning its 5k ohms into 60k ohms.
As a rule, performance is in no way impaired by resistor spark plugs. The only exception to this may be some models of high output CDI specify non-resistor plugs."
"As a rule, performance is in no way impaired by resistor spark plugs."
Wow I didn't know that. I recently changed from their "racing plug" to the same plug basically only it is a resistor plug because of my radio. I was a little hesitant to do so, but you learn something new every day
Actually I should post the whole thing, they do talk about high output CDI boxes but I think your runofthemill 6AL box isn't what they are talking about or I wonder what MSD specifies for it's 6AL box anyone know since we've been running them for 10 years or more ?
"Resistor plugs for race engines
It is strongly recommended resistor spark plugs be used in any motor that has on-board computer systems to monitor or control engine performance. Use of a non-resistor plug in certain applications can actually cause the engine to suffer undesirable side effects such as an erratic idle, high-rpm misfire, engine run-on, power drop off at certain rpm levels and abnormal combustion. Resistor plugs are also recommended on any vehicle that has other on-board electronic systems such as, two-way radios, GPS systems, depth finders or whenever recommended by the manufacturer.
If you have an outboard marine CDI (capacitive discharge ignition), (such as Johnson and Evinrude), make sure to use a plug with an inductive type resistor (such as a NGK Z-type). Inductive resistor plugs require less voltage than a monolithic (regular) resistor plug. Use of non-inductive resistor type plugs on these motors can create an open circuit within the spark plug (it will become a dead plug).
Mallory, MSD, Crane and Accel also produce a high output ignition CDI system, however, these should not be confused with a marine style CDI as mentioned above. For an automotive high output CDI system it is imperative you consult that manufacturer for plug specifications for their system. Some high out put systems specify the use of resistor plugs, while others will fry the internal plug resistor turning its 5k ohms into 60k ohms.
As a rule, performance is in no way impaired by resistor spark plugs. The only exception to this may be some models of high output CDI specify non-resistor plugs."
Last edited by MotorHead; Jan 23, 2010 at 11:09 PM.
