Read that copper is still the best material to use in spark plugs. Wish I could find the article. So what would be better to use on my 98? Copper or iridium plugs.

 

The way I understand it...coppers work better, but iridiums last longer. I couldn't convince myself there would be enough of a difference to go through changing plugs every ~25K miles if I switched to coppers.

 

Copper is a much better conductor than iridium. Platinum conducts better than iridium too.

IMO iridium plugs making more power is a gimick so people would spend $40+ for a set of plugs.

 

The big selling point of Iridium is that it doesn't wear down over time and it's such a fine strand that the spark origionates from exactly the same spot every time that it fires. Rather than jumping all around like copper or platinum.
But I'm still not sold. Running copper in both of mine.

 

Running copper in my car too. I plan to change them when putting on LT's over winter. Probably will go with the coppers again, but I like the idea of Iridiums lasting longer though.

Jason

 

Platinum lasts longer than copper too, plus they costs much less than iridium. I run the regular Bosch Plats (~$2/plug). They have a fine strand and no disk to fall off. I'm not into all that +2, +4, split/rapid fire, u/v groove stuff.

And yes I knew the iridiums last longer. I was just responding about some of the claims I've read and heard.

 

Yeah the Bosch +4's I hear are too aggressive, at least for LT1's. I just went with NGK as everyone seems to like them the best. BTW, I gapped my NGK's at .56. Could I gap them more, like down to .45 or so when I get new ones or would I be bending the electrodes too much? NGK says not to gap more than .05 than preset at the factory.

Jason

 

What's the plug #. Thanks.

 

Part #4205 at O'Reilly's. They're just the regular Bosch Plats. Cost $1.99/plug.

 

Iridium plugs are the latest & best technology out there for spark plugs. GM has switched over to iridium for servicing most of their engines built since 2000. Only Denso & NGK manufacture the plugs right now and are sold under the AC/Delco name. I recently purchased a set for my Silverado and paid $8 each for the plugs but they will last well over 100,000 miles. There is a lot of info on iridium plugs if you search google. Here are a couple links I pulled.
http://www.machv.com/denirsparplu.html
http://www.densoiridium.com/index.php?flash=0

 

Dexcool supposedly lasts 150k miles but I'm sure not going to leave it in that long.

Ya, these plugs may last that long, (Plats can last 100k), but you WILL lose power over time.

All this longer lasting stuff is designed for the people that don't care to perform simple maintenance for optimum performance.

 

The factory A/C delco plug is pretty damn good believe it or not, and is still probaly good when you think they need to be changed anyway. The high dollar super plugs are a great gimmick for the ricer crowd but don't do alot for performance. The factory's use the new technology for stock engines, burning crap gas, that they have to waranty for 100,000 + miles. If you have a special need(i.e, different heat range for nitrous, aftermarket heads) etc, just get a old school spark plug from Autolite,Champion,Denso, or NKG. Check and see how many pro racers or engine builders that use 8way Unobtainium plugs aren't pimping products out of there own speed shop. Just remember, a $12 plug will not help a weak ignition part or a bad tune. Put the money saved toward a new set of wires. Just my 2 cents.

 

I got the Iridium plugs in my engine.

The main reasons I got them is because they conduct good, and you don't have to swap them out as fast as the coppers.

Still perform great... and less maintenance.... sounds good to me!

 

iridium plugs still have a copper electrode
http://www.bimmerboard.com/forums/posts/6854

So, how is the tiny iridium electrode going to produce a more powerful spark when the electricity has to pass through a copper electrode prior to the iridium?

Again, the ONLY advantage to them is longevity.
The disadvantage is that they are about 6x more expensive.