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Geez mate i was only asking. I personally have never had any dramas. Theres no point bagging him out on a forum though, you would be better to talk to brad about it face to face. Word gets around quick in tassie remember. The reason he would have fitted the iridium plugs is because they require less firing voltage and coil demand to produce the same spark as a conventional or platinum plug, which at the end of the day is better for you. Im not trying to cause an argument here, just think you should chat to him about it.

Why do they require less firing voltage????

It might be interesting to read this thread: http://www.skylinesaustralia.com/forums/t1....html&st=20

This is not a simple discussion, the subject of spark plugs is quite complex. Following are some Skyline/Stagea specific clarifications based on my experiences;

Copper is a better conductor of electricity than iridium or platinum, so a copper plug can run a larger gap than an iridium or platinum plug. Iridium and platinum plugs are used for their life, they last longer, NOT for their performance. This is because of the increased service intervals and the high labour costs involved in changing plugs. The total cost over, say, 100,000 k’s is cheaper using iridium or platinum plugs than it is using copper plugs. That’s the case if you pay someone to change your plugs, if you change them yourself, then copper plugs are cheaper.

The numbers;

Copper plugs last for 8,000k’s and cost $18 for the 6

Iridium or platinum plugs last for 40,000 k’s and cost $120 for the 6

$18 X 5 is less than $120 X 1 = copper plugs are cheaper

But if the workshop charges you say $40 a time to change the 6 plugs = iridium/platinum plugs are cheaper.

Spark plugs come in a variety of gaps, for example NGK BCPR6ES come in 1.1 mm gap (BCPR6ES – 11) and in 0.8 mm gap (BCPR6ES – 8). Retail outlets carry the most popular part number (in this case BCPR6ES – 11). It may be that some popular N/A car uses the same plug configuration, so they carry that plug gap. It is NOT because that plug gap is somehow “standard” for that plug configuration.

As we increase boost (from standard) the inlet airflow and combustion pressure can literally blow out the spark. To overcome that we can either use higher output coils to give a “bigger” spark that will jump the gap even under the higher pressures. Or we can reduce the gap that the spark has to jump. Up to a point, reducing the gap has no real bad effects, but if we have to reduce the gap too far the engine will loose power. This is because there is simply not enough spark to properly ignite the fuel. An experienced dyno operator can pick this because he has to advance the ignition to hold the power. Advancing the ignition gives more time for the smaller spark to spread the flame. This is obviously a band aid, as we start to run into detonation problems if we advance the ignition too far.

My suggestion is (if you change your own) use copper plugs of the correct heat range and gap. If you can’t get the right gap spark plugs off the shelf, then gap them down.

Simple rule of thumb for DIY plug changers;

Standard boost = BCPR6ES – 11

12 psi = BCPR6ES – 8

Up to 19 psi = BCPR7ES – 8

Over 19 psi = BCPR7ES – 6

Until we get so much airflow that the standard coils won’t fire the 0.6 mm plug gap. Or the power drops off.

Then its time to upgrade the coil packs, go to CDI or whatever. We can usually increase the plug gap and start the process all over again.

Warning, this is not a definitive explanation, the result is a simple rule of thumb that you can employ. Then you can fine tune the slection for you own specific purposes and remember every engine is different.

:( cheers :(

It might be interesting to read this thread: http://www.skylinesaustralia.com/forums/t1....html&st=20

I know the answer, i was just curious as why he would say that they require less firing voltage :(

Launceston is the only good place in Tasmania..!!

Hahaha awesome, thanks for the reassurance mate

So Guesty you still interested in the turbo setup? Might wanna get in quick, would love to see it running around in tassie :(http://www.skylinesaustralia.com/forums/t1...38#entry3376538

Edited by ardie

No need to be a smart arse about it, the iridium plug has an electrode that is alot finer (around .4mm compared to 1.1mm) than a platinum plug which means firing voltages are decreased and spark output is increased. The melting point of the electrode is around 600-700deg higher which also means longer life.

Why should i have to prove it? Do you have a problem with people knowing more than you? Dont get your knickers in a knot with me, im just telling you why brad prefers to use iridiums, he will tell you the same thing if you bothered to listen.

Ok i think this topic has strayed from the path a little bit.

If you guys want to have a grudge match maybe take it to PM.

Fair enough guesty's had a bad experience, but I think there is a clause that says you can't slander businesses online..

Im not taking sides here either man, cos im all for the copper garden variety plugs.. and ive also never met brad in person nor had anything to do with his business.

Anyway back on topic

Anywhere except Brad Sherrif at Duggan And Parker. I went there and will never take my car back again.

Thats a big call mate. I hope you have your reasons for a statement like that!! (reads rest of thread)

He did all my tuning work and fitted Haltech E11v2 to my twin turbo RB25 and made 399rwkw @ 17psi. I wont take my car anywhere else.

Also as for the cops down here, my 33 has a external gate and did have a 4" side pipe for a while and never got pulled over (unless I was being a tool) You should have no problems unless you hoon around boosting everywhere.

Cheers,

Rob

Edited by WHITER33GTS-T

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