technical spark plug question?
10-23-2003, 03:58 PM
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technical spark plug question?
The stock S2000 plugs (after tsb) are NGK pfr7g-11s. I recently found out these are platinum. Does our engine operate at a temperature that requires platinum plugs or can I put normal plugs in it? I am tuning a nitrous sytem and they say to stay away from platinum plugs with nitrous. Irridium are supposed to be ok. I also thought about decreasing a heat range. Will this affect day to day performance? To go down a heat range what p/n (the 7 or the 11) do I change and is a bigger or smaller number a colder plug?
Thanks for any info.
Thanks for any info.
10-23-2003, 04:27 PM
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Platinum have long life. The SVT Cobra guys with huge pulley buildups swear by the copper NGK TR-6's, and generally go one range cooler. The Iridums are also popular. I do not think that it is the CC heat that is the issue as much as the ability to avoid spark blowout and stand up to the internal pressures. I used both the TR-6's and the Denso Iridiums in my SVT, and found that the misfires under high boost were lower with the TR-6 and the Denso - they performed nearly the same, but the TR6's were so muchy cheaper, and the plugs easy to change, that the Densos seemed a waste, since with high boost it is a good idea to change the plugs more frequently (and the fact that the supoercharged SVT Ciobras have NO KNOCK DETECTOR!). I will probably run the Densos in my S2K just for the longevity.
10-24-2003, 01:02 AM
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They have no form of knock sensing equipment? I wonder why... I recall this being common on older cars but perhaps I'm missing something really important.
Without KS equipment, would this suggest that the SC Cobras are tuned conservatively in order to avoid the risks of knocking and pinging?
Without KS equipment, would this suggest that the SC Cobras are tuned conservatively in order to avoid the risks of knocking and pinging?
10-24-2003, 06:22 PM
#7
Platnium are a no-no for Nitrous. I've know people that have also blew iridium plugs using Nitrous. The best plugs for Nitrous are by far regular copper plugs. It is a Must to go one step colder with the plugs. I've used copper plugs one step colder for over a year. I've gone through over 100 pounds of Nitrous. I've used iridium, , copper and a few other types. By far the best is the copper one heat range lower. Change the plugs every 10 to 20 pounds of nitrous. The insulaters take a beating under the juice. Change them every ten pounds if your bottle pressure is above 1000 psi.
The plugs take a heavy beating when spraying at 1100 to 1200 psi. You can gap the plugs to spec .38 to .42. If ya wanna play it safe gap the plugs toward the lower side. Good luck and be careful. Once ya get the plug change down it takes less than 15 minutes to inspect and change all four plugs! do it frequently! The car runs the same with the colder plugs with no performance problems when not using the juice.
The plugs take a heavy beating when spraying at 1100 to 1200 psi. You can gap the plugs to spec .38 to .42. If ya wanna play it safe gap the plugs toward the lower side. Good luck and be careful. Once ya get the plug change down it takes less than 15 minutes to inspect and change all four plugs! do it frequently! The car runs the same with the colder plugs with no performance problems when not using the juice.
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10-29-2003, 06:29 PM
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In addition to making spark, spark plugs do one other thing. They provide a gap in the electrical circuit that allows the coil to build a charge before firing. I've been racing since the 60's and have yet to discover a significan difference between plug styles, copper, platinum double gap, etc.
That being said, the equation changes drastically with NOS. Your spark plugs now have two jobs, light the mixture when YOU want it lit and don't light it when you don't want it lit. For a plug you don't want any of them little weeny platinum jobbies with the skinny center electrodes. ALL you should be worrying about is how fast your plug can get heat out of its tip and more importantly, out of it's ground electrode.
NOS heats both up really fast, so go for big FAT copper center plugs, or maybe those suface gap platinums. Get as fat a ground electrode as you can and then cut it off and bend it in so the spark goes sideways to the center rather than downwise. That keeps the side electrode, the number one source of preignition with NOS, cooler.
And don't go for a fat gap either. It just over stresses stuff. Probably .026" max. Have FUN with your Joy Jug.
That being said, the equation changes drastically with NOS. Your spark plugs now have two jobs, light the mixture when YOU want it lit and don't light it when you don't want it lit. For a plug you don't want any of them little weeny platinum jobbies with the skinny center electrodes. ALL you should be worrying about is how fast your plug can get heat out of its tip and more importantly, out of it's ground electrode.
NOS heats both up really fast, so go for big FAT copper center plugs, or maybe those suface gap platinums. Get as fat a ground electrode as you can and then cut it off and bend it in so the spark goes sideways to the center rather than downwise. That keeps the side electrode, the number one source of preignition with NOS, cooler.
And don't go for a fat gap either. It just over stresses stuff. Probably .026" max. Have FUN with your Joy Jug.