Iridium spark plugs, anyone?

[DClark]

I am not one to talk plugs as i think a lot are snakey, but I gotta tell you what happen yesterday.
I drove down to Advance Dyno in the bay area to have some headers installed and a dyno tune on my '06 GTO.
The owner told me last month that they always sap out the stock iridium plugs for copper plugs as the copper has better resistance to preignition thus allowing more power.
Well, the final pull of the dyno showed that my car had 350.68 hp. I ask if the plugs were changed- the guy forgot to change them out.So, they took them out- they had a dark rust color from the octane booster that I used. They had 19000 miles on them.
So, in went some new Champion copper plugs. The first two pulls came low. The final pull was 350.40. All in all, these brand new plugs had slightly, oh slightly less power than the old plugs. While one can quibble that it was not much of a difference, the big picture is this- plugs with 19,000 miles outperformed brand new ones! That is like an old grandma beating a teenager in a sprint.

[StevieB]

Manuf's use Iridium and Platinum plugs b/c they have a very long service life- 100,000 miles is not unheard of (My 95 Ranger went well over 100,000 on the original plugs, they were quite worn but still firing fine when I removed them.)
This long life helps considerably on the EPA requirement that the car turn in acceptable levels of pollutants for at least 50,000 miles.

I would estimate about 90% of what you hear and read in plug maker's ads is just hype. Split side electrodes, multiple side electrodes, etc.- don't do anything a well-made, properly gapped single electrode does. Spark plugs have pretty straight-forward jobs- provide an air gap that the secondary voltage can jump across, even with the high pressures found in the fully-charged compression chamber.

By it's very definition, and it's name, pre-ignition has NOTHING to do with the spark plug. Plugs fire based on the ignition timing- if they fire too soon, it isn't really pre-ignition, it's incorrect (too soon) ignition timing. Pre -ignition happens when something- carbon build up high spots, or too-high heat range plugs, other things- gets and stays hot enough to ignite the air/fuel mixture BEFORE the plug fires. Therefore, spark plug construction materials have nothing whatsoever to do with pre-ignition.

Sometimes it happens that a technician tries to explain something and/or develops theories of operation that are not really based on facts, but rather on what he has heard and his incomplete understanding of it. It also happens sometimes that the tech wants to believe (and wants you to believe) that he is somehow smarter than the engineers who designed the vehicle. I am not saying that engineers are smarter than technicians (frankly, often engineers give very little thought to what is actually going to happen in the real world- next time you have to snake your arm around a hot exhaust manifold, a VERY hot Cat. converter, and through a space half the size of a normal hand to remove ONE bolt, you will know what I mean), it's just that engineers have research resources that techs don't- and the time to replicate a condition over and over again so that they see what happens. They can do things like running an engine the equivilant of 100,000 miles in only a few days or weeks, setting it up in the lab and going home for the weekend while the load simulator does the grunt work for them.

You don't say what the first two copper plug runs were, but the difference between the first and last runs is less than 1%- well within experimental error, essentially the same reading. The most correct conclusion is no difference. And as I mentioned above, the plugs you removed had about 80,000 miles to go before they MIGHT be done.

But don't bother disabusing your tech of his misconceptions- his mind is already made up, don't confuse him with the facts.

[DClark]

You over simplified it. A plug that gets too can cause preignition. Hot plugs have longer insulators, shorter insulator is a colder plug. I used to run hot plugs to prevent fouling- I'd go on these doughnut runs when it was 14 degrees and since the plugs didn't reach opperating temp, they'd foul soon.
Dual electrodes can last longer as two electrodes where instead of one. They can even add a slight amount of timing advance, Now, before you say "WTF", with a dual plug, both electrodes never fire at the same time. Rather, the electrode with the lesser resistance gets the spark. This benefit has diminshing returns with four electordes. In fact, the extra electrodes can shroud the spark, causing actual ingition to occur slightly later. FWIW, I emailed NGK years ago which plug was bst for my bike and they said it was their dual electrode one.
Platinum plugs offer long life as the platinum will erode slower. However, platinum is not as good a conductor of electricity and will give a less intense spark. It also will get hotter and yes, as I said before, preigntion will be more likely to occur. This is why guys that add blowers to their cars don't run them.
Iridium has promised to offer the life of a platinum plug, but the conductivity of a copperplug or better.Is it hype? The dyno is the judge, everything is just bull$hit! My old iridium plugs with 19000 miles slightly, ever so slightly, out performed the coppers. As for the the other runs, I don't recall the exact numbers. I woke up at 4;00am to drive 3.5 hours to get there and was exhausted. I did video tape a lot of and will watch it later. However, I do remember that the first two runs of the coppers were over a hp less, almost 2, than the old iridiums. I was thinking "WTF?!!!". The owner had HPT software, monitored for KR action and said it was as good as it gets.FWIW, Advance is one of the best tuning shops out on the west coast- people drive as far as from CO to get their cars modded and tuned there, so I trust them.
One thing that stands out about iridium is the claim that it gives a better spark. The tip is needle fin, like a racing plug, which can help a weak ignition. I think the Katana has a weak ignitiion. Here's why i think that- I measured the voltage to the coils many years ago and I think it was only around 8v. What's the voltage coming out the coils then? Twenty thousand volts? Maybe! for a engine with a relatively low compression ration, these bikes have a very small plug gap. I have Dynocoils already to help with the spark, but wish I had more. Good iridiums might make for a a better running katana.

[gaillarry]

I switched to iridiums on my 1100 and noted that the bike started on the first crank.

[SupRnatural]

good info

[jeremy]

They work great in my powerstroke diesel.

[StevieB]

Interesting point you make about dual-side electrode plugs, I suppose that could be true. Yes, perhaps I did over-simplify the effect plug heat range would have on pre-ignition, but I pegged this as a discussion about the effect of spark plug conductor material on engine power output, not on the relative effects of all or several plug design parameters. I was trying to keep my input on-topic.

If I appeared to be ragging on the shop, I am not- just saying I have heard some otherwise very good techs say some pretty wild things, and those kind of statements tend to be driven by ego, rather than solid info.

Here's an example: First job out of college was as service advisor at a Porche-Audi dealership. The Stuttgardt-factory trained Porche tech liked his little cult of personality he enjoyed among the Porche customers, a bit too much. He gave out advise like this: the best thing to use to clean your windshield prior to putting Rain-X on it was a can of Coca-Cola. Now, Coke may do a great job, I haven't really tried it. But one day, I suggested that perhaps a can of club soda might do a better job, as I could not imagine the sugar helping to clean the windshield and club soda is sugar free. You would have thought I had accused him of not knowing to open the hood! He got very defensive. A person with a scientific frame of mind would have at least given it some thought, whereas an ego-driven thinker would have... gotten defensive.

[DClark]

Club soda to clean a windshield? I think you are both off! I think the phospheric acid in the coke helps, but the sugar doesn't. It would make more sense to use vinegar. And yes, I think the guy is an idiot.
My best friend did a year long internship in Germany with Porsche. His boss, who he car pooled with, was one of the main designers of the the 944 and they commuted in one of the first 944's made. However, he didn't come back with crap about using coke to clean windshields, though he did have some funny stories!
Anyhow, my theory is that Iridiums, by virtue of a better spark, will make a katana run better, maybe make a bit more power, and certainly help cold running/starts. They would serve as a crutch for a weak stock ignition, just like my dynacoils. However, I think the real thing to get is a dyna ignition.The owner of a local shop with a bike dyno said that one of those really woke up his personal bike, an '88 GSXR 1100 and rave about the adjustability and extra power he got, but I wonder if some of that was from simply more power for the plugs.AS he had seperate filters, I am sure all that spark helped make them a bit less finnicky. On my GM cars, GM seems hell bent on having ignitions that have the power of Thor in them- all that juice can't hurt, eh?

[SupRnatural]

I switched to iridiums on my 1100 and noted that the bike started on the first crank.

Brand & part # by any chance?

[gaillarry]

Brand & part # by any chance?

NGK, DR9EIX, # 4772, one thing with iridium plugs, you do NOT gap them, they are preset. When you get them you'll note the fine point on the plug.

Club soda to clean a windshield? I think you are both off! I think the phospheric acid in the coke helps, but the sugar doesn't. It would make more sense to use vinegar. And yes, I think the guy is an idiot.
My best friend did a year long internship in Germany with Porsche. His boss, who he car pooled with, was one of the main designers of the the 944 and they commuted in one of the first 944's made. However, he didn't come back with crap about using coke to clean windshields, though he did have some funny stories!
Anyhow, my theory is that Iridiums, by virtue of a better spark, will make a katana run better, maybe make a bit more power, and certainly help cold running/starts. They would serve as a crutch for a weak stock ignition, just like my dynacoils. However, I think the real thing to get is a dyna ignition.The owner of a local shop with a bike dyno said that one of those really woke up his personal bike, an '88 GSXR 1100 and rave about the adjustability and extra power he got, but I wonder if some of that was from simply more power for the plugs.AS he had seperate filters, I am sure all that spark helped make them a bit less finnicky. On my GM cars, GM seems hell bent on having ignitions that have the power of Thor in them- all that juice can't hurt, eh?

I've been thinking about getting dyna igntion coils. What type would I get?

[DClark]

I've been thinking about getting dyna igntion coils. What type would I get?

Well, as i said before, having a set in my bike, I think you'd be better served spending your money elsewhere, but since you have your heart set on some dyno coils, here goes:
They make two types- a high impedance and a low impedence set. Pick the wrong one and you'll damage your ignition and buy that Dyno ignition as a replacement
I think I got the low impedence ones, but don't hold me to that- go measure your stockers with a meter!!!
You will also need some new plug wires. The stock wires are glued into the coils and mine were brittle looking. Do not get some super zooty looking wires! I made that mistake. Most aftermarket wires are 8mm, the katana uses 7mm. The 8mm won't fit right into the stock plug boots. After I said %#$!*!!!, I noticed that my Autolite wires I had left over from my VW Fox were perfect- they had ends that would fit into the coils, solid copper core, silicone jacket and they fit neatly into the stock plug caps. Expect to pay about $40 and they often run rebates. Oh, and be careful with the stock plug boots as they cost around $25 each! NGK makes a similar looking boot for 1/3 the cost, but they don't fit as well- they were not as tall and are harder to remove. With ignition, the quality of the parts is not as important as the fit of the parts and their tightness. FWIW, My autolite wires are ten years old and still going strong! If you go this route, you might want to be a bit adventurous and make the gaps on your plugs slightly wider than spec to see if it helps or hurts. Report back on your findings and good luck!

[StevieB]

Club soda to clean a windshield? I think you are both off! I think the phospheric acid in the coke helps, but the sugar doesn't. It would make more sense to use vinegar. And yes, I think the guy is an idiot.

Well, I never really tried it, I use window cleaner. I just thought that whatever was in the Coke that did the cleaning, there would be more of it if the sugar was missing.

Actually, the guy was not an idiot, just a typical prima donna auto tech- and I have run across LOTS of those. They all seem to want everyone to accept everything they say as the final word. Frankly, I think it is hiding a low self-esteem and fragile ego.

[DClark]

That reminds me of something funny that happend over on the detailing part of the GTO board a few months ago.
There are guys who are wax snobs who only use Zaino/Pinnacle of the pricey Zymol stuff. They wax forever about how all that crap is far superior to stuff like the lowly Klasse /Collinte combo I use.
Well, one poster said that he got some pure white carnauba and was going to use his know how (he claimed to have a phd in chemistry) to make a premium wax equal to the $1000 stuff that Zymol sells.
He sold 4oz "samples" for $75 and 16oz samples for around $180 ( I don't remember the exact amount).
Some people bought it and raved about it. One guy, who claims to be a an expert detailer, detailing exotic cars in socal, called it as good as the multi thousand dollar Zymol Royal stuff.
He even became a sponsor on the web site. Then someone did some snooping and the truth came out.
He didn't have a phd in chemistry. He actually was once a distributer for Chemical Guys wax. What he was doing was taking Chemical Guys wax, repackaging it in small tins and marketing it up 10x!
All those 'experts" now looked like fools.

[SupRnatural]

There's an @ss for every seat..