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Hi all. Looking to get replacement spark plugs for my ER34 (RB25DET) with minor bolt on mods.

Which will be a better plug to use?

NGK Iriway 7 or NGK Iriway 8?

NGK Iriway Website

hi..

whichever is colder.

bye.

So guess NGK Iriway 7 it is then. :)

Hi....again....

also, if you're using standard ignition parts (as opposed to a Splitfire system), ensure your gaps are small too! (.75-.85mm).

Bye...

Edited by superspit
Hi....again....

also, if you're using standard ignition parts (as opposed to a Splitfire system), ensure your gaps are small too! (.75-.85mm).

Bye...

U will only need to re-gap to 0.7 or 0.8 if ur running higher than std boost. R u running a aftermarket ECU or boost ctrl?

Also becareful when re-gapping Iridiums, the tips r thin n can snap. I personally just run the NGK std plugs gapped to 0.7, only advantage of a Iridium is it'll last longer.

U will only need to re-gap to 0.7 or 0.8 if ur running higher than std boost. R u running a aftermarket ECU or boost ctrl?

Also becareful when re-gapping Iridiums, the tips r thin n can snap. I personally just run the NGK std plugs gapped to 0.7, only advantage of a Iridium is it'll last longer.

cool...but he did mention 'bolt on mods'....so I'm guessing that involves a boost increase....necessitating the gap closure!!! ;)

The fact that you don't have to worry about replacing them so often as compared to coppers IS the only obvious/realistic reason why we/I use them....thanx for clarifying that.

hi..

whichever is colder.

bye.

What I am about to say is what I do, up to you whether you agree or not. Colder deos not mean better. Colder means it's less likely to experience detonation, but going too cold has problems.

On r33s, they use a 5 heat range plug. R34s may use a 6. Either 5 or 6 for a stockish car should not present any problems.

I'm running a aftermarket turbo on my rb25, and making a fair bit of power. I'm still using 6. 7 heatrange fouls in my car driving on the street. 6 doesn't detonate.

IMO, for my car, I would not use an 8. 7 possibly, if I was driving it hard every minute it's driven.

The heat range of a plug of a factor of one in a specified brand is not going to make much difference in a standard reality....nor in a standard configured car.

I will be more detailed and suggest that it will not detonate in a well tuned/serviced/stock engine, or even give you any performance increase/decrease, for normal to good performance type driving.

ok...to avoid the niggles....I will rephrase.....

"the colder of the 2 YOU HAVE SPECIFIED"

Also, if you are going to up the boost in future (God bless ya!!), gap the plugs now, to <>.8mm to avoid the dead spots when accelerating under higher boost!!

Much info to be found around here on this topic and why it happens!!

Your car will still perform well even when boosting standard PSI with the lower spark gaps!

Sorry guys...this ain't rocket surgery!!!...let's not confuse this guy into oblivion!!!....geesh!

anyways....and least you're using a reasonably good quality plug, that's within the heat range required for your car!...enjoy.

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