Spark plug gap question.

JasonMiller94SC

Registered User
I've been running the autolite 103's for the past year and I'm thinking about going with the Iridium plugs this year. I'm not sure what to gap them at. The 103's I had gapped between 35-40 but Santa brought me a new screaming demon coil pack and a set of livewires. I'm running 16-17 pounds of boost and the car made 290 rwhp without nitrous and 340 rwhp with a dry shot. Should I keep the gap the same with the new plugs/wires/coil or can I open it up to around 45-50? :confused:
 
I'm using Denso IT20 Iridiums gapped at .040. They may work just as good at .050, but changing plugs is too much of a pain in the azz to experiment. Since your using nitrous, I would not go any looser that .040.

David
 
I had read several post where people were running the plugs at .040 but I had not found one that they were doing so with an upgraded coil. Was hoping to open it up a bit with the new coil. Where is the best place to get thoes plugs?
 
I have the same question. Screamin' Demon says to gap .065". :eek: I assume this is not what the highly modded SC should be at, especially those running a program for N20? So, David N, .040" huh?

Do you guys think the Demon benefits are wasted if spark gap is not increased?
 
I have the same question. Screamin' Demon says to gap .065". :eek: I assume this is not what the highly modded SC should be at, especially those running a program for N20? So, David N, .040" huh?

Do you guys think the Demon benefits are wasted if spark gap is not increased?

I don't believe that we should gap our plugs that much. I too have the Screamin' Demon coil...and based on all advertising information, I believe that gap to be for the n/a 3.8.

On my moderately modified SC, I don't see a problem at all running the stock gap of .054"...I'd tighten that gap up a bit for N2O. I'm not running N2O though, so I'll keep the stock gap until I start having issues. Iridium plugs are supposed to fire with less energy than traditional plugs too. I'm not sure if the coil produces more energy as they advertise, but I guess we'll see. If it does, then I don't see any issue running the stock gap...

Before installing the coil, I was running .045" with the stock coil. Not sure if I needed to close it up at all, but I did.
 
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