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your wrong on this one man. go open up a super street or dsport. most of the guys boosting 40+psi and making 600+hp are running iridium plugs as well. if i have to ill go home tonight and scan in a couple of articles to show that a lot of boosted guys are switching to iridium plugs. in last month dsport there was even a skyline gt40 that uses iridium plugs. i know of several guys on my other forum s10forum.com that also use iridium plugs with their boosted applications. they are more fail proof. using a copper plug with a boosted application could cause problems depending on how long they have been in the car and what the tune is like. think about it if the life decreases with every spark then you could end up with a weak spark in a cyl and cause it to detonate or not fire for that matter. then your in real trouble. NGK and denso both offer colder range plugs with iridium specifically for boosted applications. you might get some feedback from old school guys saying to use nothing but copper but the fact is that copper is old news everyone weants reliability especially with a FI motor

 
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it really doesn't matter. I've noticed my car starts better with copper, but you won't notice much performance difference with a stock engine. platinum and iridium last longer, copper you'll have to change more often.

 
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i've heard horror stories about the iridium electrode breaking off in FI apps. maybe this is only with denso plugs tho. and platinum i won't even go there.

 
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platinum you are 100% correct. but iridium is a whole new level now with them offering colder heat stages. i have never heard of anyone having problems when using iridium plugs with forced induction. but that is me. i would love to read about any stories or posts you can come up with. but its going to be hard because a tune is most important. with the wrong tune anything can happen. so the story you read may have been about someone want to blame the plugs with out proper knowledge of what really happened. but what ever the case i would love to hear about it to decifer myself.

 
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i think it would be harder for a iridium electrode to break considering its harder than copper. even though its a smaller electrode its a much harder metal.

 
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i haven't heard about colder heat ranges for iridium but that would make more sense. i've only heard of denso having the tips break (maybe cause they're smaller than ngk).

 
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I have iridium spark plugs too. So far are good.
In this forum people talking about NGK or denso but not about Champion.
They produce mainly spark plugs for aircrafts but now also for cars.
I chose the Champion iridium plug because the central electrod is iridium and the tip is Pt. BTW, if they can produce it for aircrafts then failure in cars are not gona happen .

 
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Stock -> Denso Iridium IK20 = A LOT smoother acceleration and faster pickup too. However they killed my gas mileage from stock 32-34mpg to like 29. So I took them out and the car is not running as nice as it did with the IK20's in, but at least I know my gas mileage is back (which I think is more important these days).

 
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i averaged 36mpg on one tank driving from my house to palm desert last weekend with ngk iridium plugs. the whole weekend of driving and only one tank of gas

 
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As gearbox mention it, really doesn't matter what type you use. All working fine. The electrical conductivity of the material doesn't matter too much, becouse the Ag, Cu, Au, Pt are just coatings.
What the differences are? Well, the important ones:
1. Over time the gap will change due to corrosion. Cooper is the worst in life expectancy and Iridium and Pt are the long lasting ones (100.000 mi).
2. Tip size. Smaller -> Lower voltage to make a spark

So, if you use other than Pt and Ir, then you need to frquently check the gap and adjuste it. If you use Pt or Ir the you don't need to do gapping for 100.000 mi or so.
Frequently change the spark plug is not a good idea. Honda designed the car to run with Pt for a reason.

MPG gain using Ir wersus Pt. Not really.
My MPG (90% HWY, 10% city):
Pt: 35.2
Pt: 45.3
Pt: 36.7
Ir: 47.3
Ir: 42.6
Ir: 44.6
Ir: 44.3
Ir: 42.9
As you see, I had above 40MPG with Pt too. So I can't say the Ir increase MPG, instead you driving habit does.

 
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platinum is used in our car because it runs hotter (mainly for emissions reasons).

 
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Sounds like I'm in chemistry again. Get out your damn Periodic Tables!

I just bought Denso Iridiums and in fact, I just received them today. I will see how it feels comparison wise.

 
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What abou Periodic Tables?
Let see if you get out some MPG+

 
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so which one is good?

here are the prices per pair in CANAIDAN TIRES

19.99 NGK Iridium IX
8.49 NGK G-Power Platinum
17.99 Bosch Platinum 4+
14.99 Bosch Platinum 2+
8.49 Boch Platinum
4.69 Champion Copper plus

and Laser (Double) Platinum 18.35 each from dealership :-(

 
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i would opt for the IR's i have had great experience with them and so have plenty of people here. gearbox is a very knowledgeable guy but i think his car is an oddball because he has several issues to work out.

 
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GEar just feels more confortable going with copper for the performance aspect of it and he isn't worried about changing them every oil change or so which he has stated numerous times....I agree on the Ir's i got them and notice a slight mpg gain finally of about 1-3 mpg....of course I'm stil using my Fp60.....anyone want to buy me another gallon? I've got like 2 or 3 servings of it left.....

 
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how many kms or miles will they(IR) last for?

how come ppl change their spark plugs so early... cos the owner's manual shown change every 110,000miles (176,000km) ??? any suggestion?


thx

 
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My advice is to read this ENTIRE THREAD...all your answers are within these pages.....

 
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yup copper you change more often cause the gap widens. copper is the superior conductor, iridium the small electrode kinda makes up for it, platinum is pretty much just about lasting longer.

 
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well after returning my engine to stock I decided to try the iridium again since it uses less voltage. Well after a few weeks I've been having serious starting problems. Every so often 1/5 times when I try and start the car it would just crank forever and refuse to turn over. i could let it go 20+ times and it still wouldn't start. then i start it again and it starts to putter and finally is going. Well this started happening once a day at least so i put back the old copper plugs and it has started perfectly every time the whole last week.

 
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iridiums > copper still

 
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how do you figure that? the only thing iridium does is last longer but who cares about that if they don't even work as well. copper has much higher conductivity compared to iridium. ask all the real tuners with blown motors and turbos they will all say copper is their choice. i'm never using anything else.

 
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its better cause they run cooler.

 
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um no. do some more research. they run cooler than platinum, but then again so does copper. and running cooler is important why? i think you need to read more about heat ranges and what it means if a plug is hot/cold.

 
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dude, read the past 6 pages on what we wrote before. i don't feel like reiterating the same crap i already posted

 
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to each his own. majin run your iridiums. let Steve run what he wants.

 
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ya anyway, i'd rather have the car start better despite whatever benefits i'm supposedly missing out on.

 
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this could be what your missing out on. platinums are stock, they are way cooler than copper. http://auto.howstuffworks.com/ignition-system2.htm
so the "benefits" would be less chance of detonation.

 
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uhh, are you sure you got the right part number for the iridiums?

I've used Denso iridiums and NGK iridiums on my D17 and they ran perfectly ... I noticed better throttle response with the NGK's. I've had about 2 sets of Denso IK20's and 2-3 sets of NGK iridiums. I've also owned the stock plugs (obviously) and also tried out the NGK v-power copper plugs. the NGK iridiums worked the best for me.

now I'm running Denso IK22's on my K20 and I will be running the oem NGK laser iridiums very soon.

I have never, EVER had a startup problem with any iridium plugs.

I recommended the NGK iridiums to a couple of my friends and neither of them have ever had any problems either ... one of them owns an 01 auto civic ex as well.

 
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serious gearbox we have all been over this before. just becasue the copper plug are a better conductor doesnt mean they are better for spark becasue it makes the iginition work harder to create the same spark. beyond that there is no reason the material the plug is made out of would make the car not want to start. that would either be a bad plug set of a wrong plug all together. eithere way you cant blame the plug material. it seems as though your car is a bit of a freak anyway. you have a lot of problems all the time. i cant name a single other person here that has had as many problems as your car has had. whether it be a lemon or just a freak you cant make such a broad statement that iridiums dont work as good as copper. your testing on one car that carries many problems since youve owned it. i hope things work out for you but seriously your car is one out of thousands that react differently to certain mods. that usually means something is wrong