Good choice. The iridiums are the best plug in my opinion. My 2001 s40 have 91,000 miles and I have not changed the wires, however, I changed both ignition coils at 60,000. The wires still look good on my s40. I would just change the ignition coils.

 

Thanks to all, this forum and a few others I've visited today inspired me to get to the bottom of all this copper vs. iridium/platinum crap. I do not intend to be an expert on the following subject matter, but merely an educated consumer who is tired of reading contradictions across the net.Nothing ticks me off more than arrogant individuals who seem to think they're above having to do any research.

As quoted from Nathan, a user on volvospeed.com who had just finished reading Dr. Jacobs' book on ignition systems (Jacobs Electronics) a couple years back:

"Some inherent features of Platinum plugs are that, because platinum is a poorer conductor than copper, platinum plugs require a lower initial voltage for the spark to jump the gap (compared to copper plugs) and the harder platinum electrode lasts significantly longer than the softer copper electrode. It is the lower initial voltage requirement that makes them work so well in most cars, and that messes things up for us.

"Since copper is such a great conductor (the electrons want to stay inside the copper) with a copper plug it is more difficult for the electrons to leave the copper electrode to initiate the jump across the gap. The electrons have to build up on the tip of the plug until enough voltage pressure is built up to force the electrons to leave the copper and jump across the gap thereby creating the spark. Since it takes more voltage pressure to initiate the spark jump, you get a hotter, stronger spark jumping the gap.

"On a platinum plug, (since it is easier for the electrons to leave the platinum electrode and jump the gap) fewer electrons build up at the tip, and the voltage pressure required to force the electrons off the electrode is lower when the spark jumps the gap. So the spark is not as strong or hot since not as much energy was required to initiate the spark.

"This 'feature' of platinum plugs is why weak (older) ignition systems benefit so much from the installation of platinum plugs, and why they work so well in non-turbo cars. With our turbos and the higer compression from the added boost, we benefit from the hotter, stronger spark of the copper plugs since the higher pressure (compression) tends to blow out the weaker sparks of platinum plugs."

In my research it also appears that Volvo made some changes with their OEM plugs starting sometime around 2003/2004. Before that, it is my understanding that Volvo turbos were using copper plugs. From a business perspective, it is more than likely thiswas done to lengthen the service spans between tune-ups while cars are still under warranty. But from a performance persepective, this was not done in the interest of someone who enjoys taking theirturbo to its limits on a regular basis, simply due to the differences in properties of the electricaland thermal conductionof copper and platinum.

For some technicalinsight on the differences between copper, iridium, and platinum I recommend this site: http://www.torontonissan.ca/forums/s...?threadid=1051

My recommendation: Go with NGK BKR7E V-Power From what I've read, this would be a suitable aftermarketreplacement geared for performance and the best bang for your buck. Granted, if you're still under warranty you better use what Volvo recommends or you'll be paying for any foul-ups.

In Layman's terms: Go with copper if all you care about is performance, go with platinum if you have a powerful lustto get 100,000 miles before having to replace them.
If you do go with copper plugs, I've seen suggestions to replace them as often as 15,000-30,000 miles (but since they're only a few bucks a pop--assuming the reader is competent in replacing his/her own spark plugs--this shouldn't be a big deal). Also, for heavily modified engines, and for forced induction engines (turbos) it's generally accepted that copper plugs will provide what is needed best. If any of this is unclear or seems misguided, before posting please review the above quote and link that I've provided. If you still think I'm wrong, then please, by all means let it out. =) I'm just trying to steer away from misguided information after sifting through hours of it.

 

mike 07, you seem to intimate that none of the posters have done their home work and they/we are simply posting ***** nilly. Not true! The opinions of the posters are predicated on their knowlege and personal experience which may well supercede the knowlege that you are relying upon. The beauty of this forum is that we do not criticize our fellow posters. I have the feeling however that you truly want to set 'the record' straight and because of that, I appreciate your posting but perhaps you could in the future tone down your feelings. Once again thanks for your input.

r.

 

I have two ultimate solutions for you. You can't be dissatisfied with either of them, see attached pics.

1-Igniter plugs for turbine engines (jet engines)
2-Thunderbolt.

Downside: The energy would be much higher than what you need, and may end up melting the entire vehicle[8D].


JPN

[IMG]local://upfiles/6892/A870469BC0504EA1A4AA64A1A6F9C556.jpg[/IMG]

[IMG]local://upfiles/6892/4DD4362D1B1B4CA781A0760C2A7D5509.jpg[/IMG]

 

I want that truly hot spark from above...........

Ben thought he could capture it in a bottle..........

r.

 

My earlier post came after hours of staring at my monitor, so my apologies if I seemed to have a bit of an edge. The misguiding information that I was referring to came frommanufacturer'sclaims, Volvo dealership technicians I've spoken to who don't know anything specific regarding spark plug performance,andprivateindividuals. Some of the answers that I needed were not easy to come by. But something I forgot to reiteratethough was thatin order to get the mostout of copper plugs your ignition system needs to be able to bridge that gap with a higher voltage pressure. Withoutthe proper voltage in supply,the technology in the platinum plugs may in fact provide a smoother idle atlow rpmsas well as better acceleration for weaker systems (corroded plug wires/battery leads). ButI highly doubtthe stock ignition system on a relatively new T5, for instance, wouldn'tprovide enough voltage to get the most out of copper plugs.

lol Ilike the humor. I'm trying hard to remember, but as I recall, centrifugal and axial flow compressors ingas turbineengines (often used in conjunction with one another for the best of both worlds) provide much higher compression ratios, somewhere in the ballpark of14:1-19:1 for stoichiometric combustion of jet fuel...but the glow plug, I'm afraid would just simply cause pre-ignition, irregardless of it'sdesign application. But I hear DeLoreans are goodfor the thunderbolt ignition. Problemwith that one is the timing is always a little off. Needs endless adjustments.

 

Indeed, Mike07, you are razor sharp right.

Axial-flow comps should have higher compression ratio than centrifugals, as cents only have one or two stages for the compressor sections as compared to 13+ stages for axials, but since all my textbooks are resting in my friend's place in Vermont, I could be a bit off[8D]. Or I can just check the powerplant service manuals at work.

I have a feeling that you are an engineer in Silicone Valley? If you design LEDs, I can spend hours discussing over LEDs.

Anyway, I hope people liked the lightning, I thought it was amusing. However, it may as well make the entire neighborhood catch on fire, and in such case, RUN[8D]!!!

Thanks for thorough research result, even I'm now thinking of using copper plugs for my future Volvo (would I be only 40 something, or would I have to wait & save until I'm 90 something[8D]?).


JPN