Ahhh, I love to report to you people when things that I do works out great.
For those of you who have missed my post on the Spoon Racing Sparkplugs: http://www.s2000online.com/forums/showthre...p?threadid=3107
Had about 5 fill-ups after the Spoon's Iridium Spark Plug install, but last three fill-ups I began to notice the mileage improvement not to mention that the car is running great bringing more smiles to my face.
It seems to me that the mileage improvement is about 15-20 miles more than what I used to be getting. I certainly seem to be able to travel more before deciding to gas up.
I also have the Spoon throttle body installed along with the spark plugs and it also may had to do with the improved fuel mileage.
I also have the FuelPressure Regulator and tinkering for a while. But I set recently at 50Psi and have been enjoying great low to mid end acceleration.
Anyway I will report to you about the spark plugs more if you want, but I am very happy with the result that I am seeing now.
This is definitely recommmended mod to all of you. I give high high thumbs-up for Spoon Iridium Sparkplugs.

You can join in the group-buy to buy or contact Mr. Giampiero at MG Racing to get you the plug'n'play Spoon Racing spark plugs.
Anyway, don't hesitate to try them, you will love them.

Could somebody explain why different sparkplugs would affect gas milage or anything else except the life of the plug?

ughhghhhhh.......... no.

This is an old thread that was dredged up, but I will repeat the spark plug story.

Different plug materials have different properties, with copper being an excellent electrical conductor, iridium being very good, and platinum being just adequate. But material life in the harsh conditions of the combustion chamber must also be considered, with copper being short lived, iridium long lasting, but platinum very long lasting. Obviously the car makers use platinum because it lasts a long time which is required for emissions requirements and has adequate performance.

Plug gap is important because performance requires the largest reliable spark that can be produced. Generally a larger gap will produce a bigger spark but requires a good conductor and will be less reliable than a smaller gap. A larger gap an be used in a NA engine as compared to FI (including nox) as spark failure is more common in those conditions.

Typically you will see a highly tuned FI engine using copper plugs with a modest gap for reliable spark, a highly tuned NA engine using larger gaps which are possible with iridium, and the OEM engine with platinum plugs and a smaller gap (but meeting emission regs for 100K).

For those skeptics please note that Honda has done on the RSX-R exactly what we have been doing on this board.. installing iridium plugs with a larger gap. In fact the OEM plugs are NGK versions of the Denso's we have been buying.

So what is the differnce in the gap from the OEM plug to the iridum plug?

I have a degree in mechanical and electrical engineering, so let me take a try.

well, it is not just the gap, but the exposed electrical "kernel" - the fine element of the Iridium makes it easier to optimize the spark shape for good light off of the air/fuel charge. That is the theory, and it is reasonable. Spark plug indexing will produce higher dyno output, and that is all about how the plug spark is oriented relative to the incoming charge. With the Iridiums (Iridia?), they are almost self indexing.


High quality plugs will reduce spark misfiring, although comparative tests of Denso TR6's (copper) vs. the Iridiums showed the TR6 was nearly as good, and far cheaper. If the plug is easily accessed, a good copper plug is what i plan to use. BTW, I lashed up the test gear to measure the number of misfire over the rpm range over time, so i will vouch for the results.

I did put a set of Iridiums in the Cobra, which is not that bad to get at, but the Platinum OEM plugs byte it.