Just put a set of NGK iridium plugs in the bike. No real difference that I can see. People claiming that they last nearly twice as long, however.
John.
John.
Why Iridium ?
- Thread starter nicholas
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Explains a few things..AA didn't spec the Iridiums for my car, only one platinum, and the copper NGKs and the Champions it came with.. I don't have NOX, but I do have 10:1 compression.
That is interesting. I have an Oldsmobile Aurora with a 4.0L Northstar motor with 10.3:1 Compression, and the Iridiums are specced for my car. As a matter of fact, it comes with thin electrode platinums stock.
Wonder if "High Compression" means even higher compression...
YES like 12.0+:1 would be High Compression. Or severely boosted engines. 10.5 or under with premium gas and Iridium plugs is just fine.
But your Top Fuel Funny Car, Pro Stock stuff is all Copper core. Heck even the surface gap F1 plugs I saw were copper core.
But your Top Fuel Funny Car, Pro Stock stuff is all Copper core. Heck even the surface gap F1 plugs I saw were copper core.
Yikes. We need a bobistheplugguy website...either that or people need to brush up on plasma physics.
It's really not "fine point hot spots" that are the problem. Anytime you modify a stock engine that raises the amount of heat thats needs to be dissipated from the spark plug, you run the risk of heating the plug outside of it's intended heat range. Copper Core plugs just have an inherent "wider heat range". A properly fully engineered spark plug, and I'm talking about taking in account heat flow through the plug, CC, head, etc, made out of platinum or iridium could be made to work in any application. Such engineering doesn't run in the realm of faart-can muffler tuners. And race engine's plugs will likely be replaced after every race so no exotic metals are needed.
In OEM applications, longlife double platinum and/or iridium are designed to reach a desired temperature to keep deposits from forming, because if deposits form, it doesn't matter if the gap has been maintained with the use of the exotic metals. So they're operating at the upper end of their heat range.
And it should be mentioned that there's a big difference in the quality and intended use of various platinum and/or iridium plugs. Replacing OEM longlife double platinum plugs with something like NGK Iridium IXs would actually be a step backward in quality and life potential. If you replace your serviceable OEM longlife double platinum plugs with Iridium IXs and get a performance boost, you have deficiencies in your ignition system, not the spark plugs.
Here's some additional info:
http://www.aa1car.com/library/2004/us30428.htm
Where are you finding that Iridium plugs are a step down in quality and service life from platinums? The article you quoted specifically says that Iridium has a MUCH higher heat resistance, making it better for wear, requires less voltage to fire, and are, and I quote "an excellent upgrade for engines that were not originally equipped with these types of plugs."
Where are iridium plugs worse? Cost? Everything I have found in my own research for getting plugs for my new car says that iridium is a good upgrade. Yes, more expensive, but worth it.
Besides, in most applications, platinums do not last that well. We all have had or at least, heard of poor performance with Bosch Platinum plugs, never mind the lower service life.
And while the original platinum plugs that come in a lot of cars WILL still work at 75 to 100k miles of use, measure the gap of those plugs. It is going to be a good bit bigger than it should be.
Patman
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He is correct, when you compare OEM double platinum plugs to aftermarket iridiums (which only are made of iridium on the one side) the service life is a lot shorter on the iridiums. I contacted NGK about the service life of their iridiums and it's only about 50k, compared to 100k for OEM platinums or OEM iridiums.
My local Chevy Dealer recommended the AC Delco 41-985 (12571164) Iridium over the OEM PZTR5A15(12567759) double platinum plugs for quality and service. Was I being mislead?
I recalled that NAPA Auto Parts had the NGK TR55IX Iridium plugs on sale for $6.99 that month and went with them. I could not discern a difference in performance with Iridium vs Double Platinum after the installation. Was this a "step back" in quality?
Bowser
Patman
Staff member
I don't necessarily think it's really a step back in quality, in fact I've got a set of NGK TR55ix plugs sitting right here which are going into my Corvette at my next plug change. But they have a shorter service life, they definitely won't last 100k in there.
At the same time I don't think I would ever leave OEM plugs in there for 100k anyhow. In the case of my 98 Corvette, it came with the lesser quality AC Delco platinums, the ones which have the platinum "pucks" on them, and these ones always come apart. When I pulled these plugs out at 32k, all of the platinum pucks were gone! I replaced those with copper NGK plugs, and have been using them for a while, and decided to give the iridiums a try to see how they compare.
At the same time I don't think I would ever leave OEM plugs in there for 100k anyhow. In the case of my 98 Corvette, it came with the lesser quality AC Delco platinums, the ones which have the platinum "pucks" on them, and these ones always come apart. When I pulled these plugs out at 32k, all of the platinum pucks were gone! I replaced those with copper NGK plugs, and have been using them for a while, and decided to give the iridiums a try to see how they compare.
My bad, I should of said "service life" instead of "quality". But the other related point I was trying to make is that just because a plug is made with "Iridium" which is newer that "Platinum" which is newer than "Copper Core", etc, doesn't necessarily mean the plug has a longer service life or is of better quality. As you mentioned, AC Delco platinums, the ones which have the platinum "pucks" on them that always come apart, is a step backward in quality from regular copper core plugs. On the otherhand, I had a set of OEM Denso double platinums (with platinum pucks) that went 125K miles without a problem. All the pucks were intact, and when checked on a scope, all were firing just fine before I replaced them. The replacements were like $14/each, even when bought at a discount online.
So yes, your copper core NGK or NGK/Denso Iridiums may be a step up in quality compared to those AC Delco platinums (and some of the other junk out there), but not compared to the OEM NGK and Denso long life Platinums. And if you search real hard, you can find NGK and Denso long life Iridiums that are even better. So I think we're in agreement, Patman.
For the least amount of potential hassles, you ought to use what's spec'd unless you're trying to solve an inherent problem.
You can get the OEM spec'd (NGK Iridium plug IFR6T-11, Denso Iridium plug SK20R11) for $8.07/$9.35 respectively. Use the proper anti-seize as previously suggested.
One difference in after-market Iridium plugs and OEM style plugs is that after-market plugs are .4 mm not the .7 mm like the OEM.
And when you change the identical heat range plug of the same manufacturer from Iridium to copper core both with the same gap and one pre-ignites and detonates and one runs fine then you have some idea what I am talking about.
Yes that motor had several set of plugs trying to get the pre-ignition/detonation down and all it took copper core plugs.
back to stock stuff
If you can get the .7mm wire and platinum tipped ground strap they go 100K all the time.
And when you change the identical heat range plug of the same manufacturer from Iridium to copper core both with the same gap and one pre-ignites and detonates and one runs fine then you have some idea what I am talking about.
Yes that motor had several set of plugs trying to get the pre-ignition/detonation down and all it took copper core plugs.
back to stock stuff
If you can get the .7mm wire and platinum tipped ground strap they go 100K all the time.
In a stock engine originally equipped with Iridiums? I find that hard to believe.
Patman
Staff member
Some Corvette C6 owners are reporting mild part throttle pinging even with bone stock cars.
Copper plugs are less likely to cause pinging compared to platinum and iridium. In order from most to least, it goes platinum, iridium, then copper. So perhaps some of these people who are experiencing mild pinging might be able to eliminate it with the switch to copper plugs (the stock C6 plugs are made of iridium)
But those are pretty unique situations, since GM has tuned these engines right on the edge, they make pretty high compression for a street motor. They really do need 93 to 94 octane for sure too, so that's another factor at play.
Copper plugs are less likely to cause pinging compared to platinum and iridium. In order from most to least, it goes platinum, iridium, then copper. So perhaps some of these people who are experiencing mild pinging might be able to eliminate it with the switch to copper plugs (the stock C6 plugs are made of iridium)
But those are pretty unique situations, since GM has tuned these engines right on the edge, they make pretty high compression for a street motor. They really do need 93 to 94 octane for sure too, so that's another factor at play.
No that one was a highly modded engine with a supercharger. But you get the idea. Was making the point about what happens in the extremes.In a stock configuration more important is to make sure if you have DIS that the plugs are compatible and then the proper heat range. In hard to service cars you should consider the longer service life of Double Platinum and or Irdium Designs.
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