Iridium Spark Plugs

I'm aware that there will be no power benefit from them, just better wear and more expensive. However, when I picked up my plugs (DPR8EIX-9), I didn't reaqlize that the Roadster uses the 7 heat number and it's llisted in the owners manual also.
The question is, will the bike perform OK with them ore hsould I go for the 7 numbers and shelve some new $58.00 paper weights.lol
With my exposed oversize triples, Jardine headers and tune with timing changes, would the cooler plugs maybe help as far as detination and still have the headt to run clean?
Any thoughts here or am I worrying over nothing. I'll probably go ahead and pick up the right ones tomorrow.
Later
BTW I have 6000Mi on my bike and the stock plugs looked real good. They're just one heat number hotter than what I have installed. Seems the only real problem would be if the plug is too hot.

Put in the new plugs, and make a quick run up through the gears and coast down. No idling or cruising.

Let the engine cool, and then pull the plugs.

Look for a line on the ground strap of the plugs. The line should be located half way between the base and the tip. If it is lower, try one heat range colder. If it is higher, try one heat range hotter.


That said, the R3 engines are not particularly sensitive to heat range until you are making considerably more power - and the combustion chamber heat that comes with it.

I hope this helps.

With the low compression of a stock engine the heat range is not significant to doing damage to the piston crown. A hotter plug should just be more fouling resistant in a stock application (that includes Jards, triple K&N and a retune). Until you fettle the compression ratio higher you won't see any difference other than cold weather idle and start. Those are both better with the Iridiums.

Thanks for the replies.

I've been making shorter trips since I don't commute anymore lately. I've been seeing that it runs a bit rough and seems to load up unless run a good distance. I'm thinking a hotter plug would help me out too. (probably just better gas) lol

Power-Tripp said:

Put in the new plugs, and make a quick run up through the gears and coast down. No idling or cruising.

Let the engine cool, and then pull the plugs.

Look for a line on the ground strap of the plugs. The line should be located half way between the base and the tip. If it is lower, try one heat range colder. If it is higher, try one heat range hotter.


That said, the R3 engines are not particularly sensitive to heat range until you are making considerably more power - and the combustion chamber heat that comes with it.

I hope this helps.

Click to expand...

I had never heard of that method of calculating what heat range to run. That's interesting.

Rocket Scientist said:

I had never heard of that method of calculating what heat range to run. That's interesting.

Click to expand...

The plugs will tell you a lot, if you know how to read them.