Sparkplug recommendations?
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,270
It was always my understanding that the resistor plugs lowered RFI emissions, but as you say they dissipate some spark energy. First OE use was 1969. It probably doesn't make much difference with TI because that system delivers double the spark energy of the single point system, which has less reserve energy.
BTW, two equivalents of the long discontinued non-resistor AC 45 for small blocks is the Denso W14-U and NGK B4.
Duke
BTW, two equivalents of the long discontinued non-resistor AC 45 for small blocks is the Denso W14-U and NGK B4.
Duke
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,053
Likes: 4,194
From: US-PNW
Resistor plugs have a (smaller) secondary air gap vs non-resistor plugs which have none. If I remember correctly, one advantage was to reduce misfiring and cross firing from induced voltage from spark plug wire routing. But obviously, jumping the secondary gap results in less spark energy at the primary ignition gap inside the combustion chamber.
Duke or others will likely have additional information to share.
Larry
Duke or others will likely have additional information to share.
Larry
It was always my understanding that the resistor plugs lowered RFI emissions, but as you say they dissipate some spark energy. First OE use was 1969. It probably doesn't make much difference with TI because that system delivers double the spark energy of the single point system, which has less reserve energy.
BTW, two equivalents of the long discontinued non-resistor AC 45 for small blocks is the Denso W14-U and NGK B4.
Duke
BTW, two equivalents of the long discontinued non-resistor AC 45 for small blocks is the Denso W14-U and NGK B4.
Duke
Race Director
Joined: Apr 2005
Posts: 11,263
Likes: 2,130
From: Bowling Green, Kentucky
Read this article. Has pics of secondary air gap as well as some detail regarding its function. http://corollaperformance.com/TechInfo/sparkplugs.html
I clearly remember the Hot Rod magazines back in the late 1960's showing the differences in spark plug design: resistor and non-resistor. Typically the drawings and info were from Champion. I still have the articles. Obviously a lot has changed and improved over the last 50 years regarding spark plug design.
Larry
Safety Car
Joined: Mar 2002
Posts: 3,780
Likes: 442
From: Southwest MI
I would personally say 44, especially if you actually drive the car as intended. But, let’s see what the more enlightened here have to say :-). (in my personal inventory all I have is 43s and 44s, never had the desire/need for anything hotter)
