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Originally posted by bbenny

hey price is about $19.50ea

I dont know what u should gap them too. i know for turbo RB engines its 0.8mm but on the packet the iridiums say not to change the gap because the tips are very fine and fragile.

I gapped them to 0.8 anyway and they have been pretty good.

By gapping expensive iridium spark plugs, as far as i know, voids the purpose of getting expensive iridium spark plugs, as what you pay for is the coating, which is removed when you gap them.

I may be wrong....

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well i gaped them by tapping the top of the bent curve without fitting anything in between just to make sure no surfaces were scratched, so there was no chance of the coating being removed. i then just used a feeler guage to check gap distance.

Worked perfect, much better than the platinums. so im sure its not a problem as long as you are careful.

Iridiums are gapped at 1.1 by default. I am using them at 1 bar boost and have absolutely no problems, the mixture is perfect and there are no flat spots or anything, so I'm not sure why you'd need to regap them when running any normal sort of boost. Maybe with even higher boost you might need to gap them a bit smaller, I don't know.

Ths only platinums I've used are the old ones that were in the car when I got it, so I can't really say if the Iridiums are "better". But everyone seems to need to re-gap their platinums, so for not having to re-gap the iridiums makes them seem worth the extra couple of bucks to me. Not for the time/effort saved, but the fact that you can have a more universal gap (ie just forget about it).

  • 1 month later...

akeenan: in your great wisdom, can you tell my why my NGK coppers melted? I think that Coppers are only asking for trouble after the latest stint..... All of the plugs were stuffed (the little finger was melted off ever single one). I think after that I can justify the price of iridiums

Sumo

I have to correct myself about the Iridiums gap too. I'd been told that it was 1.1mm. I decided to expierment with changing the gap awhile ago to help eliminate flat spots. I pulled the first plug out and checked the gap, and it was 0.7mm. Oh well, nothing more to do there :)

the only ngk plugs specified for a r33 gtr are platinum or iridium no copper ( i'm sure u can find copper though but wouldnt last )and the diff in price is only $2 , iridiums last a bit longer , i dont know that they are any better though .

akeenan: in your great wisdom, can you tell my why my NGK coppers melted? I think that Coppers are only asking for trouble after the latest stint..... All of the plugs were stuffed (the little finger was melted off ever single one). I think after that I can justify the price of iridiums  

Sumo

no i cannot tell you why they melted. sorry..

Running lean or detonation is the main cause of plugs melting isn't it? If so, maybe copper plugs would serve as a good warning device. Better a melted plug than a melted piston!

I am under the impression that the new technology plugs come set at the right gap for the application. Correct me if I'm wrong, but setting the gap in sparkplugs was dome in the low-tech days when the electrode wore away much more than it does with electronic controlled ingnition systems.

what heat range would be best for RB25DET? I was told heat range 6 is good, but some ppl here uses heat range 7??

At what boost level you should use 6 and 7?

And someone also told me the suitable gaps is 0.8mm ?

using platinum or iridum they can have a very fine tip witch produces a better spark . u can have a fine tip with standard nickel but the life expectancy would be very short thats the reason the nickel tips are much bigger ( longer life )the platinum on the tip doesnt burn as easy so it lasts much longerand iridium longer still ( they claim iridium give a better spark as well .

i wouldnt use nickel on any of my cars , i only use platinum but next time i'll try iridium as they are only $2 more .

there are 2 types of iridium ngk sparkies....

the difference is in the centre electrode (tip) size.. 0.8mm and 0.6mm.

0.8 is the same size as plats so they are only better by lasting longer.

0.6mm one has better spark and uses less voltage but only lasts same distance as the platinum ones. also when you order em make sure u tell em to get the model without the -11 at end cause then they will come gapped to .8mm not sure the code for the RB's. you dont want to gap them the traditional way cause you might scratch off the iri coating which defies the getting em in first place!

i used to use the v-groove copper ones but with the iridium's engine does feel smoother and seems to hold boost better.

just put platinums in mine and noticed a slight improvement. dont know if the iridium ones would make much difference. a few guys i know have said that they didnt notice any difference between platinums and iridiums. they will probably just last longer.

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