Spark Plugs: Iridium vs Platinum vs Copper?

[sharkspoo]

I changed my plugs (copper) at 91K. My 964 currently has 103K and I just purchased a new set of wires. I want to replace the plugs while I am doing the wire swap. Does anyone have background on what would be most beneficial Iridium vs. Platinum vs. Copper? There are also variations of 1 vs 2 vs 4 electrodes on the Platinum. Of course all of these variants come at a multitude of prices.

Thanks!

[lucittm]

shark,
For the 964 you can install the least expensive plugs that cross-reference to the plugs specified by the factory for size, reach, tip projection, and heat range. For the 965 only the Bosch single electrode platinum plugs in the proper heat range (WR6 DP0) will work.

I wondered why and the Bosch guy told me the turbo boost makes the center electrode glow red and only the platinum conducts the electrical charge well at that temperature. He said a regular plug can be "snuffed out" at the higher compression ratios that the boost generates due to reduced voltage caused by the tip temperature. I guess it makes sense but I sure wish those plugs didn't cost $12.00 each.

He also told me to always use resistor plugs because, contrary to popular belief, it does not cut down on the spark voltage but it does reduce a bit of backward reflected electrical noise (he called it the snap at the tail of the dragon) caused when the plug fires across the gap. I asked him about multiple electrodes and he laughed. He said it is a marketing gimmick and Bosch is guilty as hell for doing it too.

Mark

[e3photo]

Thanks Mark,
I guess this would also apply to 993's. It is easy to get lost in the hype.

Cheers,
Emerald

[sharkspoo]

Thanks Mark! I appreciate the feedback! There are alot of claims out there of cleaner burn, more power, etc.....