Iridiums

[Bwah MR2 GT]

Does anyone suggest not putting in iridiums?

More drain on the leads/cap and quicker burn out - but more spark under high pressure and better chamber burn yeah?

Currently running NGKs set to .7mm

Worth the small investment to upgrade? Or not worth the hassle.

Cheers from downunder.

[MR2Jedi]

The Iridium tip is tiny and there are stories of the tip melting off and causing big time distruction in the block for the turbo models. I was using them for a very short while but removed them when I heard this.
They don't give anymore spark than any other plug. The element Iridium just gives longer life like the platinum.
Most guys runs the copper NGK's like you and me. The Platinums are OK.

[tgidavid]

Toyota's and Nissan's use iridiums on all new cars sold. Maybe they didn't get the memo on strained ignition components and broken tips.

[MR2Jedi]

Originally Posted by tgidavid

Toyota's and Nissan's use iridiums on all new cars sold. Maybe they didn't get the memo on strained ignition components and broken tips.

On the turbo models?
I have not experienced this catastrophe myself, but just reading about it kinda freaked me, so I yanked the plugs out and went with the Copper NGK's.

[buddah55]

I have used iridium SP's on all my MR2 including the 89 SC MKI i own now. I have never had any issues with them whatsoever. I have been using them on my current 2 for going on 3 years now with no issues.

From all the stuff i've read though it seem that turbo's may be prone to ceramic breakage more than N/A because of Detonation. MR2BAD is correct when he mentions the reason to use Iridium plugs.

Here is a posting from Denso's FAQ site. at http://www.densoiridium.com/faq.php

"Q. What kind of performance will I get from this plug?

A. Generally, you do not purchase spark plugs for performance enhancement. While DENSO Iridium Power spark plugs have contributed to numerous accomplishments through dyno-testing and actual use, their true benefit lies in their efficiency, durability, and improved firing power. Serious tuners modify their vehicles by increasing boost through turbo-chargers, super-chargers, and Nitrous. They are also known to add high-energy ignition systems, tinker with timing, adjust fuel mixture ratios, and increase horsepower through other means. Putting these kinds of demands on their engine increases the need for an efficient, durable spark plug that can handle these kind of harsh environments. That’s where DENSO Iridium Power can make a major difference.

I've always kept in mind that the insulator is what takes the brunt of the high temperature abuse, so logically speaking since the plugs last longer without needing to be replaced the insulator becomes brittle and lends to breakages.

The big benefit in my humble opinion of using iridium plugs aside from them lasting longer is the fact that ridium spark plugs require on average 5,000 fewer volts to fire than conventional spark plugs.
Less power is required to fire which makes the burn a more efficient burn.

As far as what to use? I can only share my experience.

"They make fun of us cause we are different... We make fun of them because they are the same"
---- The Freak.. (rip) WYYX 97X --circa 2000----

[MR2Jedi]

^ Interesting read.
I'm curious, you use these plugs in your 2's. How much boost were you running? The stories I've heard (though no actual evidence) about the breakages were under high boost.
Like I stated before, I used them for awhile without incedent, but didn't want to chance my engine on them.(after hearing the story) I run alittle higher boost than stock, 15-16psi, which is not all that high.

[buddah55]

And i'm thinking that's why the cases i've read where it has actually happened has been with folks that are using turbo's..

My 2 is pushing right at 10-13 according to the gauge i have connected. it's one that was installed before i bought the car so i'm not sure how accurate a read it is.. the other 2's i had were N/A...

I'll have pics of mine up soon.

[MR2Jedi]

Originally Posted by buddah55

And i'm thinking that's why the cases i've read where it has actually happened has been with folks that are using turbo's..

OH,My comments about Iridium failures were only aimed at Forced Induction engines. They are safe for N/A's.

Originally Posted by buddah55

I'll have pics of mine up soon.

Cool, I'll keep and eye out for them..

[Bwah MR2 GT]

Ta for the interesting read and feedback - good stuff.

I put in iridiums and cleaned/oiled the K&N over the wk end, and I s*#t you not, it is running the best I have ever had it. As soon as I started it I heard the difference - so smooth. And the drive is just stunning, like I've picked up 20% horse.

On another thread I wrote about the cause for this question - which was engine running rough at 4K in each gear. It is completely sorted now with the plugs and filter.

Interesting.

I had cleaned the filter only 2K ago, so I think I must have had a dud spark - but not sure how. THat is, it was not ever missing, and had good power to 4K.

I run SW20 91 Gen 1 at 14 psi. It does concern me re the tip, as it is tiny, but it must be made with tolerances - typically they are used in LPG which has a hotter burn (doesn't it?) and the marketing is focussed on better spark for longer - so I would be thinking that this issue someone had once with the tip breaking off might be an anomaly.

Whilst it is running so well (maybe I just needed a hotter plug - ratio issue or maybe it was the filter!) I am going to leave it.

I have never got a performance boost from a plug change before, so it is really an interesting event.

If anyone is interested, I used the NGK Bkr6eix iridium plugs, replacing the bkr6ep-7's

Cheers