put longevity aside is there a performance difference between copper,platinum and iridium spark plugs?? like what would happen if I put a copper plug on a car originally equip with an iridium or platinum? I notice almost all the mustang forum I go to they seem to all recomend a copper NGK plugs on the mustangs originally equip with platinum plugs..
spark plug comparison
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No performance difference provided you use a plug that has the same reach, nose tip, and heat range as oem.
I think it's some kind of internet myth that keeps propagating. What I've read/heard mostly is that a copper plug will prevent preignition better versus a platinum or iridium, because on paper copper conducts heat better than platinum or anything else. Or it might be because on paper copper conducts electricity better than the other metals. The conclusion is it'll then give you better performance, and of course, more power, more fuel economy, etc.
People are easily misled because they don't know what materials are where in a spark plug.
The core of the plug including platinum and iridium is copper. The center electrode, on traditional plugs which are referred to as copper plugs, is not copper. It's a nickel alloy, and probably contains copper but will contain other metals as well. The ground strap, which is what you always check to make sure is light tan and clean, is nickel steel alloy. How much insulator is around the center electode of the spark plug which regulates it's heat range, and allows heat to flow from the center of the plug into the block, and has nothing to do with copper or the center electrode material. If anything, the smaller center electrodes of iridium will be able to run cooler because there's less material surface area. So there's no truthful performance benefit regarding heat transfer or electrical conductance, it's #@$%!. Simply select the proper heat range spark plug, along with the correct reach and nose tip.
the only performance benefit I'm aware of comes in when you make the center electrode as thin and as sharp as possible. That reduces the voltage required for a spark to jump the gap, which results in more reliable high rpm performance. Key word is reliable, but will of course be marketed as more power, greater fuel economy, cause the driver to get more chicks, etc.
The tradeoff is the thinner/smaller the center electrode the easier and quicker it will erode, and when it erodes the gap opens and can cause a big performance drop. Platinum has greater erosion resistance than the traditional copper (alloy) and lasts longer. I don't think the center electode sizes differ anything significant from traditional (copper) to platinum, they are 2mm I think, so the only performance benefit is after 100k miles the traditional plug will have eroded enough to have a higher chance of misfiring due to increased gap or rounded center electrode compared to a platinum plug. Iridum is more erosion resistant than both and is able to be thinner and not erode. NGK has 0.7mm and denso has 0.4mm iridium center electodes, but their ground straps are still nickel steel.
Now what can happen, which I'm sure has and then these people get myths started, is they cross reference their oem plug to bosch, autolite, whoever, and the heat range is not the same or the reach of the plug is different or the projected tip of the plug is different. Then the engine runs different and they bash the plug as being junk rather than themselves for not knowing what they're doing.
some good sources of spark plug info:
http://en.wikipedia.org/wiki/Spark_plug
http://ngkaz.home.att.net/wsb/html/view.cgi-home.html-.html
http://www.madehow.com/Volume-1/Spark-Plug.html
http://www.sparkplugs.com/sparkplug411.asp
I think it's some kind of internet myth that keeps propagating. What I've read/heard mostly is that a copper plug will prevent preignition better versus a platinum or iridium, because on paper copper conducts heat better than platinum or anything else. Or it might be because on paper copper conducts electricity better than the other metals. The conclusion is it'll then give you better performance, and of course, more power, more fuel economy, etc.
People are easily misled because they don't know what materials are where in a spark plug.
The core of the plug including platinum and iridium is copper. The center electrode, on traditional plugs which are referred to as copper plugs, is not copper. It's a nickel alloy, and probably contains copper but will contain other metals as well. The ground strap, which is what you always check to make sure is light tan and clean, is nickel steel alloy. How much insulator is around the center electode of the spark plug which regulates it's heat range, and allows heat to flow from the center of the plug into the block, and has nothing to do with copper or the center electrode material. If anything, the smaller center electrodes of iridium will be able to run cooler because there's less material surface area. So there's no truthful performance benefit regarding heat transfer or electrical conductance, it's #@$%!. Simply select the proper heat range spark plug, along with the correct reach and nose tip.
the only performance benefit I'm aware of comes in when you make the center electrode as thin and as sharp as possible. That reduces the voltage required for a spark to jump the gap, which results in more reliable high rpm performance. Key word is reliable, but will of course be marketed as more power, greater fuel economy, cause the driver to get more chicks, etc.
The tradeoff is the thinner/smaller the center electrode the easier and quicker it will erode, and when it erodes the gap opens and can cause a big performance drop. Platinum has greater erosion resistance than the traditional copper (alloy) and lasts longer. I don't think the center electode sizes differ anything significant from traditional (copper) to platinum, they are 2mm I think, so the only performance benefit is after 100k miles the traditional plug will have eroded enough to have a higher chance of misfiring due to increased gap or rounded center electrode compared to a platinum plug. Iridum is more erosion resistant than both and is able to be thinner and not erode. NGK has 0.7mm and denso has 0.4mm iridium center electodes, but their ground straps are still nickel steel.
Now what can happen, which I'm sure has and then these people get myths started, is they cross reference their oem plug to bosch, autolite, whoever, and the heat range is not the same or the reach of the plug is different or the projected tip of the plug is different. Then the engine runs different and they bash the plug as being junk rather than themselves for not knowing what they're doing.
some good sources of spark plug info:
http://en.wikipedia.org/wiki/Spark_plug
http://ngkaz.home.att.net/wsb/html/view.cgi-home.html-.html
http://www.madehow.com/Volume-1/Spark-Plug.html
http://www.sparkplugs.com/sparkplug411.asp
Well put. A proper iridium replacement plug has only one benefit that I can see: longevity. That's why I am gonna pony up for a set of NGK IX plugs for my Hemi this week. Those suckers are not easy to replace and I do NOT wish to do it more than I bl00dy well have to...
John.
John.
My NGK Iridium IX plugs made a noticeable improvement in my Mazda Turbo. Immediately had it Dyno'd. Dyno owner was so impressed he fitted then to his Subaru B4 Liberty and older Subaru turbo engine (not sure what model it is). Worth every cent
I replaced the copper plugs in the 84 dodge PU this week with NGK iridium plugs & it made a difference in how it ran. The plugs that came out were all good, none were fouled & only had maybe 1500 mi on them. Only thing I can think of is the long intake manifold on the I-6 creates different mixtures on each cylinder which the iridium deals with better. Now to get one for the lawnmower & snowblower & I'll be 100% iridium.
Check the NGK website. It shows the better flame front from Iridium plugs.
well i tend to disagree on most na motors a good iridium plug is hard to best but supercharged engines typically don't like them. al least in the Pontiac 3.8 sc they don't however the ls1 crowd seems to really like the denso iridium so it seems you just have to find what your motor "likes"
Copper plugs can have copper in the core, or a side electrode that is filled with copper.
It is used for it's thermal properties.
The vast majority plugs are resistor plugs, and any tiny increase in electron flow when using copper would be of no consequence.
It is used for it's thermal properties.
The vast majority plugs are resistor plugs, and any tiny increase in electron flow when using copper would be of no consequence.
if you think about it the less voltage required to fire iridium plugs should be better in a supercharged or boosted engine. The problem lies in the heat range of the spark plug and the ability to gap the plug properly. Higher cylinder pressures require increased voltage for a spark to jump the gap. Since the power of the coil is limited, you close the spark plug gap to maintain spark. I forget the rule of thumb, something like 0.004 or 0.005" for every 5 or 10 psi of boost or something. They recommend you not regap platinum or iridium plugs but you can usually close the gap on almost any plug. It would be this reason, along with not getting a platinum or iridium plug in the proper heat range why a boosted engine wouldn't like a particular plug. It's not the plugs fault, it would be the person's fault for using an incorrect plug or a plug incorrectly.
well i was more commenting on the fact that iridium being a poor conductor not just of electricity, but of HEAT
You can't gap an Iridium plug. What are you on about?
Why can't you gap a plug because of it's tip material?
Of course you can.
Of course you can.
You can gap iridium plugs, you need a special gapper though, the regular cheap coin one sold at auto parts stores won't work.
There is no electrode over the tip so how can you gap an NGK Iridium IX plug?
There direct correlation, based on dyno tests, of an increase in HP as plug gaps are increased, up to the point of misfire. Remember the old days when widening the gap would smooth a rough idle?
An iridium plug is capable of running a wide gap based on the melting point and erosion resistance of its center electrode which allows the electrode wire to be rather fine and thus concentrate electric charge in order to better ionize the path between electrodes and conduct a sustained spark. The long life of these plugs is due to the iridium metal itself, plus the ability of the plug to fire with an erosion widened gap.
A long gap is susceptible to being "blown out", and some super or turbocharged engines, along with some big bore high compression engines may require a shorter plug gap than the iridiums come with out of the box. High energy ignition systems can solve this problem and still allow a clean ignition with a wide gap.
An iridium plug is capable of running a wide gap based on the melting point and erosion resistance of its center electrode which allows the electrode wire to be rather fine and thus concentrate electric charge in order to better ionize the path between electrodes and conduct a sustained spark. The long life of these plugs is due to the iridium metal itself, plus the ability of the plug to fire with an erosion widened gap.
A long gap is susceptible to being "blown out", and some super or turbocharged engines, along with some big bore high compression engines may require a shorter plug gap than the iridiums come with out of the box. High energy ignition systems can solve this problem and still allow a clean ignition with a wide gap.
brad d now I come to think of it I can't remember. They have done 92,000kms fitted a very long time ago. Getting old and maybe my memory is tricking me. I'll pull one tomorrow and check it out. Could be an apology coming on...s
Another consideration with plugs to consider. On (most) dohc engines with the plug centered straight up the plug boot has to reach down and fully engage the sparkplug AND is molded to seal or snap into the head cover. I've experienced plugs that have the correct size and heat range that cross reference for the application but are slightly shorter at the terminal end of the plug. The result is plugboot that feels like it's snapped all the way onto the spark plug and into the head cover but is not. My experience has been eventually at least one boot gets loose and that cylinder develops a miss fire or the arcing at the loose terminal starts to give problems. Example of this is ND plugs used as replacement for NGK in many bike application. The ND is 1mm short which doesn't seem like much, but the way the boots are molded for the dohc head covers 1mm can make a difference.
From my experience in my car, the factory Champion Double Platinums are junk. After 24k, I was noticing rough idle and inconsistent revving, so I took them out(such a pain in this car) and the gaps were all so different. I regapped them, but the smoothness only got me another 4k miles.
So I replaced them all with NGK IX iridium, and they have been excellent so far! I also replaced the OEM wires with MSD wires because they are prone to failure past 30k...
I decided upon the NGK plugs because they are a brand I trust, and I wanted them to last awhile, since it is such a pain swapping plugs on my engine!
So I replaced them all with NGK IX iridium, and they have been excellent so far! I also replaced the OEM wires with MSD wires because they are prone to failure past 30k...
I decided upon the NGK plugs because they are a brand I trust, and I wanted them to last awhile, since it is such a pain swapping plugs on my engine!
JHZR2
Staff member
out of curiousity, how is it so tough to change plugs on a PT cruiser???
in my experience, 4 cyl engines are by far the easiest types to change plugs in.
JMH
in my experience, 4 cyl engines are by far the easiest types to change plugs in.
JMH
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