DUI Screamin' Demon coil and high zoot plugs
#1
10-06-2010, 04:50 PM
DUI Screamin' Demon coil and high zoot plugs
Since I'm modding for low- to mid- range power and high elevation operation, I'm about to start fooling around with the ignition system a bit to ensure that it'll very reliably light the fires at low RPM and high elevation. And of course do the same on the flats at highway speed. Since cranking up the voltage to support a wider spark gap has worked for me on other engines in the past, I've got (in a box) the DUI Screamin' Demon coil with cap, rotor, and wires to match. The part that's got me puzzled now is the spark plugs to mate up to those things.
Performance Distributors (the DUI folks) said only that they recommend Autolite Platinums "because they are very good about maintaining the wider plug gaps we recommend with our ignition systems". I didn't pursue it further, just assumed that they were stretching the gaps beyond Autolite's recommended limits. That's something I'm not too keen on doing after seeing the relationship of the center and ground electrodes on a 3923 with the gap set to .060" -- the ground electrode's terminus was right around the equator of the center electrode, which (it seems to me) would wear that ground electrode quite rapidly.
Has anyone tried fiddling with the Screamin' Demon and spark plugs to find the optimum plug for one of these small block Magnums? I can't find a good reference anywhere. All I find are folks cracking the gaps on the factory recommended plugs open. I dunno... it could just be me but that seems kinda halfass.
FWIW, I've got a set of NGK IZFR6K-13's ("Laser Iridium", proper thread and reach, gapped to .051") sitting here on my desk and I'm going to give them a try in a few weeks when I plunk everything else into place. And some plain old V-Powers just in case things come up strange, too. My plan is to run the iridiums in the driveway at around 1200RPM up to normal operating temp, then pull a few to look them over. If all looks good, I'll do some around town driving then pull and inspect a few again. And if that's good, it'll hit the interstate for a three hour tour, a three hour tour... with parts and tools on hand in case I get a twitchy feeling.
But if someone hereabouts already has some similar experience I'd dearly love to hear of it.
Performance Distributors (the DUI folks) said only that they recommend Autolite Platinums "because they are very good about maintaining the wider plug gaps we recommend with our ignition systems". I didn't pursue it further, just assumed that they were stretching the gaps beyond Autolite's recommended limits. That's something I'm not too keen on doing after seeing the relationship of the center and ground electrodes on a 3923 with the gap set to .060" -- the ground electrode's terminus was right around the equator of the center electrode, which (it seems to me) would wear that ground electrode quite rapidly.
Has anyone tried fiddling with the Screamin' Demon and spark plugs to find the optimum plug for one of these small block Magnums? I can't find a good reference anywhere. All I find are folks cracking the gaps on the factory recommended plugs open. I dunno... it could just be me but that seems kinda halfass.
FWIW, I've got a set of NGK IZFR6K-13's ("Laser Iridium", proper thread and reach, gapped to .051") sitting here on my desk and I'm going to give them a try in a few weeks when I plunk everything else into place. And some plain old V-Powers just in case things come up strange, too. My plan is to run the iridiums in the driveway at around 1200RPM up to normal operating temp, then pull a few to look them over. If all looks good, I'll do some around town driving then pull and inspect a few again. And if that's good, it'll hit the interstate for a three hour tour, a three hour tour... with parts and tools on hand in case I get a twitchy feeling.
But if someone hereabouts already has some similar experience I'd dearly love to hear of it.