Iridium plugs

[JustenGT8]

I'm looking to try Iridium plugs to extend the stock ignition system as far as i can. Currently no probs with 17psi but a shift to 20psi could push the old U a bit

So general comments on a suitable heat range to use and anyone got source that does a decent price? Best i can do so far is $90AUD delivered from the US for a set of 8

[Grega]

justen
i can't help you with heat range but bosch have just brought out a range of plat plugs which seem somewhat better priced than the NGK (i don't know how good they are though)

[30psi 4agte]

from what i have read ....... conventional steel plugs give the best power and are most effective from a performance point of view.

I dont think switching to iriduim plugs will give any benefit to the ignition output of your system justen.

Im only going from the test results posted in zoom magazine a year or so ago when they tested most of the big name plugs only to find the cheapest plug out of all of them ( champion ) gave the best results.


As far as heat range goes.. what do you have now and what do they suggest for std ?

At a guess id say somewhere around the 8's

[Fish]

THE CHAMPION GOLDS also they tried a plug called direct hits. gave the best power but fucknose where to get them.

[oldcorollas]

the platinum and iridium plugs supposedly give the spark better access to the mixture, and also because they always fire from the same thin tip, have a better cleaning action, as well as the Pt and Ir less prone to corrosion etc.

if your mixture is too rich, or the plug too cold, you will still have issues of fouling, but if engine is tuned right, the Pt/Ir should give better results, due to the geometry of the tips.

i'm of th eopinion that NGK make some of the best plugs, (and rebrand for many "tuning house" plugs), but maybe others are ok

multi ground electrodes are silly

heat range.. 1 range higherer than standard for turbo car or 2 ranges higher than NA?
so an NGK 7? if they overheat, go to 8's, but 8 may be too cold if you are tootling around
(sorry occifer, i had to clean my plugs )

\/\/, sometimes experience is better than theory .. maybe NGK isn't expecting such high cylinder temps perhaps?

[Norbie]

FWIW the 2JZ guys shy away from platinum/iridium plugs after the boost has been cranked up a bit, they don't perform as well and the more fragile tips are more likely to get munted. I tried one set of iridiums in my car (running ~18psi at the time), they were shit and I switched back to copper in less than a week.

[JustenGT8]

Hmmm, i currently run champion golds have done for years and these give no probs at 17psi.

The basis of this move was that the thinner electrode is supposedly less prone to getting snuffed out at higher boost. Seems not to be the case based on the 2J experiences?

[fixeruperer]

platinum and iridium plugs need less power to fire aswell, so that could help you ignition system a little bit.
im not a fan of platinum/iriduim plugs id use them in an everyday car but not a performance one.

go cdi ignition you can have like a 2mm gap and 30psi of boost hehe.

[JustenGT8]

Not quite looking to spend $800 plus for an extra 3psi of boost on an interim engine

[whatthe?]

I run coppers in the 1J at 21psi, no issue. NGK BKR7

Used to run platinums in the 7M though, no issues with them either although I ran less boost through that.

Like Norbs I've always been told coppers give the best spark as well. No complaints from me and theyre dirt cheap!

[JustCallMeOrlando]

Depends how easy they are to change too dude The XX was a doddle, but the 1UZ I'd imagine would be a bit harder. Stephs WRX was never not getting anything but iridium or platinum

[allencr]

Aren't they really for stable performance over a long period of time - no maintenance for 40,000mi/km/whatever and not much better then anything else for performance right now?
If this is a performance engine, its plugs should be looked at more frequently to find out how they're burning.

Please, can anyone post a site about 'copper' plugs that isn't just full of advertising BS! I've searched.

[Dieseltrain]

I run NGK Iridiums gapped down to 0.72mm and run up to 20psi without any issues!

I think the 2JZ guys have dramas cause they try and use 1.1mm gapped units...

I buy the 0.8mm gap ones and degap them a little bit. I might get a New set some day soon and do a back to back dyno test of Copper vs Iridiums on my setup.. Ive never run coppers though, as ive run some pretty decent numbers.. I guess it pays to be the odd one out?

[psychofox]

I'm not speaking from a FI viewpoint, but in the NA engines I have used (2ZZ, 4AGE, 4ag20v) have used iridium plugs with great success. I have used the NGK Iridium IX and they have a 0.6mm centre electrode. Iridium has a very high meltoing point (upwards of 2500deg C) so you won't be melting the electrodes any time soon. The cheapest I have found them in Australia is at a place www.performancelub.com

[TWNCAM]

In my 4age N/A i found that it ran a bit worse when i put copper plugs in so i went and put platinums in it which is actually the recommended plug by Toyota and it runs heaps better and there good for around 100,000k's depending on driving style, Tune etc but with FI i'd think it would be the same case as a copper plug has a lower melting point to a platinum one and the platinums are mostly regarded as a long life performance oriented plug i found all this out as i used to work at Repco Campbelltown